Engine Controls - System & Component Testing - Eec-V Ford Econoline I

INTRODUCTION

Before testing separate components or systems, perform appropriate procedures in BASIC DIAGNOSTIC PROCEDURES article. Since many computer-controlled and monitored components set a Diagnostic Trouble Code (DTC) if they malfunction, also perform procedures in SELF-DIAGNOSTICS - EEC-V article.

Note. Testing individual components does not isolate short or open circuits. Perform all voltage tests with a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use ohmmeter to isolate shorted or open wiring harness. For identification of circuits and terminals referenced in test procedures, see WIRING DIAGRAMS article.

Ground Circuits

1. Turn ignition off. Locate PCM. See POWERTRAIN CONTROL MODULE LOCATION table. Using a DVOM, check continuity between ground and PCM connector pins. See IDENTIFYING PCM GROUND PINS. (Scheme 1) If continuity does not exist, repair open ground circuit as necessary. If continuity exists, go to next step. IDENTIFYING PCM GROUND PINS Application PCM Ground Pin No. Continental, Crown Victoria, Grand Marquis & Town Car 3, 25, 51, 77 & 103 Contour, Cougar & Mystique 24, 51, 77 & 103 Econoline 4.2L & 4.6L 24, 25, 51, 76, 77 & 103 5.4L 3, 24, 25, 51, 77 & 103 6.8L 3, 23, 24, 25, 51, 76, 77 & 103 Expedition & Navigator 3, 25, 51, 77 & 103 Mustang 24, 25, 51, 76, 77 & 103 3.8L 24, 25, 51, 76, 77 & 103 4.6L 2-Valve 3, 25, 51, 77 & 103 4.6L 4-Valve 25, 51, 77 & 103 Pickup F150 & F250 4.2L & 4.6L 24, 25, 51, 76, 77 & 103 5.4L 3, 25, 51, 77 & 103 Super-Duty Models 3, 23, 24, 51, 76, 77 & 103 Ranger 24, 25, 51, 76, 77 & 103 Sable & Taurus 24, 25, 51, 76, 77 & 103 Taurus SHO 3, 23, 24, 25, 51, 76, 77 & 103 Windstar 3.0L 24, 51, 76, 77 & 103 3.8L 24, 25, 51, 76, 77 & 103
2. Touch negative lead of voltmeter to a good ground. With vehicle running, backprobe positive lead of voltmeter to each ground terminal. Voltmeter should indicate less than one volt. If reading is greater than one volt, check for open, corrosion or loose connection on ground lead.

Power Circuits

Turn ignition off. Using a voltmeter, check for battery voltage between ground and PCM terminal No. 55 (KAPWR). Turn ignition switch to START or RUN position. Check for battery voltage between ground and PCM connector terminals No. 71 (VPWR). If battery voltage is not present, power is not being supplied from PCM power relay. See TEST B under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.

POWERTRAIN CONTROL MODULE LOCATION

Identifying PCM 104-Pin Connector Pins. Scheme 1

ENGINE SENSORS & SWITCHES

Note. For additional sensor testing specifications, see appropriate SENSOR OPERATING RANGE CHARTS article.

Clutch Pedal Position (CPP) Switch

See TEST TA under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article for testing procedures and specifications.

Inertia Fuel Shutoff (IFS) Switch

Ensure ignition is off. Locate IFS switch. See appropriate INERTIA FUEL SHUTOFF (IFS) SWITCH LOCATION TABLE (CARS) or INERTIA FUEL SHUTOFF (IFS) SWITCH LOCATION TABLE (TRUCKS & VANS) table. Shake or jar IFS switch to cause switch to open. IFS switch reset button should pop up. Fuel pump should not operate and car should stall. Push down on reset button. Restart engine. Fuel pump should operate.

INERTIA FUEL SHUTOFF (IFS) SWITCH LOCATION (CARS)

INERTIA FUEL SHUTOFF (IFS) SWITCH LOCATION (TRUCKS & VANS)

Park/Neutral Position (PNP) Switch

See TEST TA under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC- V article, for PNP switch testing procedures.

Engine Coolant Temperature (ECT) Sensor

Sensor uses a 5-volt reference voltage during engine operation. To check ECT signal voltage, backprobe between signal terminal and ground with engine running. To check sensor resistance, disconnect sensor connector and measure resistance between sensor terminals. For ECT sensor specifications, see ECT SENSOR SPECIFICATIONS table. For additional testing information, see TEST DA under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.

ECT SENSOR SPECIFICATIONS (1)

Heated Oxygen Sensor (HO2S)

Faults in sensor or circuit should set a Diagnostic Trouble Code (DTC). See QUICK TEST in SELF-DIAGNOSTICS - EEC-V article. To check HO2S heater resistance, go to step 34) of TEST H under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.

Intake Air Temperature (IAT) Sensor

Sensor uses a 5-volt reference voltage during engine operation. To check IAT signal voltage, backprobe between signal terminal and ground with engine running. To check sensor resistance, disconnect sensor and measure resistance between sensor terminals. For specifications, see IAT SENSOR SPECIFICATIONS table. For additional testing information, see TEST DA under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.

IAT SENSOR SPECIFICATIONS (1)

Mass Airflow (MAF) Sensor

Faults in MAF sensor or circuit should set a Diagnostic Trouble Code (DTC). See QUICK TEST in SELF-DIAGNOSTICS - EEC-V article. If no diagnostic trouble code has been set, go to TEST DC under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article for MAF sensor and circuit testing.

Output Shaft Speed (OSS) Sensor

Faults in MAF sensor or circuit should set a Diagnostic Trouble Code (DTC). See QUICK TEST in SELF-DIAGNOSTICS - EEC-V article. If no diagnostic trouble code has been set, go to TEST TJ under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article for OSS sensor and circuit testing.

Throttle Position (TP) Sensor

Ensure none of following conditions exist

1. Binding throttle linkage.
2. TP sensor loose or not seated properly.
3. Throttle plate not fully closed.

Faults in TP sensor or TP sensor circuits should set a Diagnostic Trouble Code. See QUICK TEST in SELF-DIAGNOSTICS - EEC-V article. If no DTCs are present, see TEST DH under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article for additional TP sensor testing and specifications.

RELAYS

Note. To identify fuel pump relay terminals, refer to numbers molded on relay. Two different numbered relays are used. Fuel pump relay terminals may be numbered 1-5 or terminals may be numbered 30, 85, 86, 87 and 87A. On relays that are numbered 1-5, terminals for relay coil are terminals No. 1 and 2. On relays that are numbered 30, 85, 86, 87 and 87A, terminals for relay coil are terminals No. 85 and 86.

Fuel Pump Relay

1. Turn ignition off. On fuel pump relays that terminals are numbered 1-5, measure resistance between relay terminal No. 1 and all other relay terminals. Resistance should be 40-120 ohms between terminals No. 1 and 2 and more than 10,000 ohms between terminal No.1 and other relay terminals.
2. On fuel pump relays that terminals are numbered 30, 85, 86, 87 and 87A, measure resistance between relay terminal No. 85 and all other relay terminals. Resistance should be 40-120 ohms between terminals No. 85 and 86 and more than 10,000 ohms between terminal No.85 and other relay terminals. On both relays, if resistance is not as specified replace relay. If resistance is okay, see TEST KA under SYSTEM TEST in SELF-DIAGNOSTICS - EEC-V article for additional fuel pump circuit testing procedures.

Fuel Shutoff Valve Relay

Note. To identify Fuel Shutoff Valve (FSV) relay terminals, refer to numbers molded on relay. FSV relay is also referred to as fuel valve relay.

1. Turn ignition off. Measure resistance between terminals No. 85 and 86 at FSV relay. Resistance should be 40-120 ohms. Also measure resistance between terminal No. 85 and terminals No. 30 and 87 at FSV relay. Resistance should be more than 10,000 ohms. If resistance is not as specified, replace FSV relay.

Canister Vent (CV) Solenoid

See FUEL EVAPORATION under EMISSION SYSTEMS & SUB-SYSTEMS.

EGR Vacuum Regulator (EVR) Solenoid

See EXHAUST GAS RECIRCULATION (EGR) under EMISSION SYSTEMS & SUB-SYSTEMS.

Idle Air Control (IAC) Solenoid Resistance

See IDLE AIR CONTROL SOLENOID under IDLE CONTROL SYSTEM.

Supercharger (Boost) By-Pass (SCB) Solenoid

1. Turn ignition off. Disconnect SCB solenoid connector. Measure resistance between SCB solenoid terminals. If resistance is not 68-78 ohms, replace solenoid. If resistance is 68-78 ohms, IAC solenoid is okay. See TEST KJ under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article for additional testing and specifications.

With Fuel Pressure Gauge

Remove fuel tank cap to release fuel tank pressure. Connect Fuel Pressure Gauge (T80L-9974-B) to pressure relief valve (Schrader valve) located on fuel injection manifold rail. Using a suitable container, release fuel pressure.

Without Fuel Pressure Gauge

If fuel pressure gauge is not available, disconnect Inertia Fuel Shutoff (IFS) switch. For IFS location, see INERTIA FUEL SHUTOFF (IFS) SWITCH LOCATION TABLE (CARS) or INERTIA FUEL SHUTOFF (IFS) SWITCH LOCATION TABLE (TRUCKS & VANS) under ENGINE SENSORS & SWITCHES. Remove fuel cap to release fuel tank pressure. Crank engine for 15 seconds to release system pressure.

See RELAYS under RELAYS & SOLENOIDS.

System Integrity Check

Perform the following checks

1. Visually inspect fuel system (fuel lines, filter, pump, injectors, pressure regulator, etc.).
2. Ensure Inertia Fuel Shutoff (IFS) switch reset button is not in upper (tripped) position.
3. Ensure battery is fully charged and fuel-related fuses are okay.
4. Check fuel tank contents and fuel gauge accuracy. On vehicles with 2 fuel tanks, check both tanks. If any fault is detected, repair as necessary. If system checks are okay, go to CHECK FUEL PRESSURE.

Check Fuel Pressure

Install fuel pressure gauge. Start engine and record fuel pressure. See FUEL PRESSURE SPECIFICATIONS article. If fuel pressure is as specified, testing is complete. If fuel pressure is not as specified, go to TEST HC under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.

FUEL PRESSURE REGULATOR

See TEST HC under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.

Fuel Injector Resistance

Disconnect injector harness connectors. Using digital ohmmeter, measure resistance between injector terminals. If resistance of any injector is not 11-18 ohms, replace injector.

Fuel Injector Check

Start engine and allow to idle. If engine will not start, crank engine for 10 seconds. Using a stethoscope, listen for clicking sound at each injector. If clicking sound is heard, fuel injector is operating. If clicking sound is not heard, go to step 57) of TEST H under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.

FUEL SYSTEM PRESSURE RELEASE

To release fuel pressure or vent fuel tank(s), see FUEL SYSTEM in appropriate REMOVAL, OVERHAUL & INSTALLATION article.

See RELAYS under RELAYS & SOLENOIDS.

Turn ignition off. Connect fuel pressure gauge to Schrader valve located on fuel rail. Observe fuel pressure gauge. Turn ignition on and note fuel pressure reading. Start engine and allow to idle. Note fuel pressure reading. Increase engine speed to 2500 RPM for one minute. Note fuel pressure reading. If fuel pressure readings are 80-120 psi (552-827 kPa), testing is complete. If fuel pressure readings are not 80-120 psi (552-827 kPa), go to TEST HB under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.

See TEST HB under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.

Disconnect injector harness connectors. Using digital ohmmeter, measure resistance between injector terminals. If resistance is not 4-6 ohms, replace injector.

LEAK TEST

Note. After vehicle has sat for several hours, a very slight natural gas smell may emanate from within intake manifold and intake air system. This is a normal condition. After several hours, fuel injectors leak down.

1. Fuel Rail & Fuel Injectors Turn ignition off. Remove Fuel Shutoff Valve (FSV) relay from power distribution box in engine compartment. To pressurize fuel system, connect a jumper wire between FSV relay socket No. 87 and 30. (Scheme 2)- (Scheme 4). Remove jumper wire and reinstall FSV relay. NOTE: To identify Fuel Shutoff Valve (FSV) relay terminals, refer to numbers molded on relay. FSV relay is also referred to as fuel valve relay.
2. Using leak detector provided with Natural Gas Vehicle (NGV) Pressure Test and Vent Kit (134-00114), check for leakage at spring lock coupling and fuel rail-to-fuel injector connections. If a leak is detected, repair as necessary and retest.

Connecting Jumper Wire To Fuel Shutoff Valve Relay Connector (Crown Victoria). Scheme 2

Connecting Jumper Wire To Fuel Shutoff Valve Relay Connector (Econoline). Scheme 3

Connecting Jumper Wire To Fuel Shutoff Valve Relay Connector (Pickup). Scheme 4

1. Fuel Tanks & Fuel Lines Verify fuel tank pressure is at least 1500 psi (10,343 kPa). If fuel tank pressure is less than 1500 psi (10,343 kPa), refuel vehicle. Using leak detector provided with Natural Gas Vehicle (NGV) Pressure Test and Vent Kit (134-00114), check for leakage at fuel tank(s), coalescer/filter and fuel lines. Coalescer/filter is located inside of left frame rail. If a leak is detected, ensure fuel line fittings are tight and retest. If leak is still present, inspect "O" ring ,"O" ring land and sealing surfaces for damage distortion or contamination. Repair as necessary and retest.

1. Upper Fuel Tank Rack Vapor Vent Box (Crown Victoria) Connect Rotunda Pressure Test Adapter (134-00122) to upper fuel tank rack flexible vent tube. Pressure test adapter is part of Natural Gas Vehicle (NGV) Pressure Test and Vent Kit (134-00114). Pressurize vapor vent box to 17 in. H 2 O. Monitor pressure for 2 minutes. Pressure should not drop more than 6 in. H 2 O. If pressure drops more than 6 in. H 2 O, apply a soapy water solution around vapor vent box gasket and seals to pinpoint leak. Replace gasket or seals as necessary. Retest system.

UNABLE TO VENT FUEL TANKS OR FUEL LINES (CROWN VICTORIA)

Note. A DVOM, New Generation Star (007-00500) scan tool and Natural Gas Vehicle (NGV) Pressure Test and Vent Kit (134-00114) or equivalent test equipment are necessary to preform the following test procedures. Natural gas vehicle pressure test and vent kit consists of Rotunda Fuel Filler Neck Venting Kit (134-00117), Venting Hose (134-00118), Grounding Cable (134-00121), Venting Tank Wiring Harness (134-00120) and Manual Override (134-00050).

Pre-Inspection

Visually inspect fuel system for damaged fuel tanks, solenoids, fuel lines/hoses, fuses, relays and loose or corroded connectors. If any faults are indicated, repair as necessary. If no faults are indicated and system will not vent, go to step 1 .

Note. Battery must be fully charged to perform solenoid diagnostics. Whenever connecting vent tool, ensure vent tool bleed valve is closed.

Scheme 5

Scheme 6

Scheme 7

Scheme 8

Scheme 9

1. Check Fuel System Solenoid Operation Turn ignition off. Disconnect Black 2-pin connectors for No. 3 and 4 fuel tank solenoid valves. Fuel tanks No. 3 and 4 are mounted on the lower fuel tank rack assembly underneath rear of vehicle. Disconnect upper fuel tank rack assembly Gray 8-pin connector, located under left side of vehicle. (Scheme 5) Insert grounding spike into earth. Connect Grounding Cable (134-00121) between grounding spike and backside of fuel fill valve at fuel line connection. (Scheme 6) Connect Fuel Filler Neck Venting Kit (134-00117) to fuel fill valve. (Scheme 7) Connect Venting Hose (134-00118) to vent stack that allows natural gas to be vented outside of repair shop. Vent stack installation must be approved by local authorities. Using a 3/16" Allen wrench, open manual backflow valve on backside of fuel filler valve. (Scheme 6) Open bleed valve on fuel filler neck venting kit for 60 seconds. (Scheme 7) Close bleed valve. Observe system pressure on fuel filler neck venting kit pressure gauge. If pressure is zero psi, system pressure is okay but all 4 solenoid valves must still be checked for being stuck closed. Go to next step. If pressure is not zero psi, go to step 15. (Scheme 5): Locating Upper Fuel Tank Rack Assembly 8-Pin Connector (Crown Victoria) (Scheme 6): Connecting Grounding Cable To Backside Of Fuel Fill Valve (Crown Victoria) (Scheme 7): Connecting Fuel Filler Neck Venting Kit-To-Fuel Fill Valve NOTE: Ensure manual lock-down on No. 4 fuel tank solenoid valve is open. (Scheme 8) The following step will supply power to fuel tank solenoid valves for 30-60 seconds. If time expires, cycle start/stop button on NGS scan tool to restore power.
2. Check No. 4 Fuel Tank Solenoid Valve Reconnect Black 2-pin connector for No. 4 fuel tank solenoid valve. Turn ignition on. Using NGS scan tool, access OUTPUT TEST MODE. Command all outputs ON to activate solenoid. Observe pressure on fuel filler neck venting kit pressure gauge. If pressure is zero psi, go to next step. If pressure is not zero psi, mark No. 4 fuel tank solenoid valve as "GOOD" and go to step 5.
3. Check Power Supply To No. 4 Fuel Tank Solenoid Valve Turn ignition off. Disconnect Black 2-pin connector for No. 4 fuel tank solenoid valve. Turn ignition on. Using NGS scan tool, access OUTPUT TEST MODE. Command all outputs ON. Measure voltage between ground and Pink/Black wire at No. 4 fuel tank solenoid valve wiring harness connector. If battery voltage is present, go to next step. If battery voltage is not present, repair open in Pink/Black wire and repeat step 2.
4. Check Ground To No. 4 Fuel Tank Solenoid Valve Turn ignition off. Using ohmmeter, measure resistance between ground and Black wire at No. 4 fuel tank solenoid valve wiring harness connector. If resistance is less than 5 ohms, mark No. 4 fuel tank solenoid valve as "STUCK CLOSED". Replace solenoid valve after completing all test procedures. Go to next step. If resistance is 5 ohms or more, repair open in Black wire between ground and solenoid valve. NOTE: Ensure manual lock-down on No. 3 fuel tank solenoid valve is open. (Scheme 8) The following step will supply power to fuel tank solenoid valves for 30-60 seconds. If time expires, cycle start/stop button on NGS scan tool to restore power.
5. Check No. 3 Fuel Tank Solenoid Valve Reconnect Black 2-pin connector for No. 3 fuel tank solenoid valve. Turn ignition on. Using NGS scan tool, access OUTPUT TEST MODE. Command all outputs ON to activate solenoid. Observe pressure on fuel filler neck venting kit pressure gauge. If pressure is zero psi, go to next step. If pressure is not zero psi, mark No. 3 fuel tank solenoid valve as "GOOD" and go to step 9.
6. Check Power Supply To No. 3 Fuel Tank Solenoid Valve Turn ignition off. Disconnect Black 2-pin connector for No. 3 fuel tank solenoid valve. Turn ignition on. Using NGS scan tool, access OUTPUT TEST MODE. Command all outputs ON. Measure voltage between ground and Pink/Black wire at No. 3 fuel tank solenoid wiring harness connector. If battery voltage is present, go to next step. If battery voltage is not present, repair open in Pink/Black wire and repeat step 2.
7. Check Ground To No. 3 Fuel Tank Solenoid Valve Turn ignition off. Using ohmmeter, measure resistance between ground and Black wire at No. 3 fuel tank solenoid valve wiring harness connector. If resistance is less than 5 ohms, mark solenoid as "STUCK CLOSED". Replace solenoid valve after completing all test procedures. Go to next step. If resistance is 5 ohms or more, repair open in Black wire between ground and solenoid valve. NOTE: Ensure battery is fully charged. The following step will supply power to fuel tank solenoid valves for 30-60 seconds. If time expires, cycle start/stop button on NGS scan tool to restore power.
8. Check No. 2 Fuel Tank Solenoid Valve Ensure ignition is off. Disconnect Black 2-pin connector for No. 2 fuel tank solenoid valve. Open bleed valve on fuel filler neck venting kit for 60 seconds. Close bleed valve. Locate and disconnect upper fuel tank rack assembly 8-pin connector. (Scheme 5) Connect Venting Tank Wiring Harness (134-00120) between male and female halves of upper fuel tank rack assembly 8-pin connector. (Scheme 9) Hold venting tank wiring harness in No. 2 position. Turn ignition on. Using NGS scan tool, access OUTPUT TEST MODE. Command all outputs ON. Observe system pressure on fuel filler neck venting kit pressure gauge. If pressure is zero psi, mark fuel tank No. 2 solenoid valve as "MAY BE STUCK CLOSED" and go to next step. If pressure is not zero psi, mark No. 2 fuel tank solenoid valve as "GOOD". Leave venting tank wiring harness connected and go to next step.
9. Check No. 1 Fuel Tank Solenoid Valve Turn ignition off. Open bleed valve on fuel filler neck venting kit for 60 seconds. Close bleed valve. Hold venting tank wiring harness in No. 1 position. Turn ignition on. Using NGS scan tool, access OUTPUT TEST MODE. Command all outputs ON. Observe system pressure on fuel filler neck venting kit pressure gauge. If pressure is zero psi, mark fuel tank No. 1 solenoid valve as "MAY BE STUCK CLOSED" and go to next step. If pressure is not zero psi, No. 1 fuel tank solenoid valve is okay. To complete diagnostics, install a new solenoid valve for any solenoid valve that was marked as stuck closed. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. If No. 2 fuel tank solenoid valve was marked as "MAY BE STUCK CLOSED", go to next step. If all solenoid valves were marked as "GOOD", testing is complete. Remove test equipment, reconnect all connectors and check system for normal operation.
10. Check Upper Fuel Tank Rack Assembly Ground Circuit Turn ignition off. Disconnect venting tank wiring harness. Open bleed valve on fuel filler neck venting kit and vent system pressure to zero psi. Close bleed valve. Remove upper fuel tank rack assembly. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Remove vapor vent box from upper fuel tank rack assembly. Disconnect connectors for No. 1 and 2 fuel tank solenoid valves. Locate upper fuel tank rack assembly Gray 8-pin connector, located under left side of vehicle. (Scheme 5) Measure resistance of Black wire between terminal No. 1 at upper fuel tank rack assembly Gray 8-pin connector and No. 1 and 2 fuel tank solenoid valve wiring harness connectors. If both resistance readings are less than 5 ohms, go to next step. If any resistance reading is 5 ohms or more, repair open in Black wire and go to next step.
11. Check For Open Circuit Measure resistance of Pink/Black wire between terminal No. 6 at upper fuel tank rack assembly Gray 8-pin connector and No. 1 and 2 fuel tank solenoid valve wiring harness connectors. If both resistance readings are less than 5 ohms, go to next step. If any resistance reading is 5 ohms or more, repair open in Pink/Black wire. Install upper fuel tank rack assembly (including vent box) and repeat step 8 to verify repair.
12. Check Upper Fuel Tank Assembly Manual Lock-Downs Check manual lock-downs for No. 1 and 2 fuel tank solenoid valves. If manual lock-downs are open, replace any upper fuel tank rack assembly solenoid valve that was marked as "MAY BE STUCK CLOSED". Install upper fuel tank rack assembly (including vent box) and repeat step 8 to verify repair. If manual lock-downs are closed, install upper fuel tank rack assembly (without vent box), tighten all fuel line connections and go to next step.
13. Check No. 2 Fuel Tank Manual Lock-Down Open No. 2 fuel tank solenoid manual lock-down jack screw. (Scheme 8) Open bleed valve on fuel filler neck venting kit for 60 seconds. Close bleed valve. Observe system pressure on fuel filler neck venting kit pressure gauge. If pressure is zero psi, mark No. 2 fuel tank solenoid valve as "GOOD" and go to next step. If pressure is not zero psi, mark No. 2 fuel tank solenoid valve as "STUCK OPEN" and go to next step.
14. Check No. 1 Fuel Tank Manual Lock-Down Close No. 2 fuel tank solenoid manual lock-down jack screw. Open No. 1 fuel tank solenoid manual lock-down jack screw. Open bleed valve on fuel filler neck venting kit for 60 seconds. Close bleed valve. Observe system pressure on fuel filler neck venting kit pressure gauge. If pressure is zero psi, mark No. 1 fuel tank solenoid valve as "GOOD" and repeat step 8. If pressure is not zero psi, mark No. 1 fuel tank solenoid as "STUCK OPEN". Replace any upper fuel tank rack assembly solenoid valve that was marked "STUCK OPEN". Install upper fuel tank rack assembly (including vent box). Check system for normal operation.
15. Check For Short To Power Turn ignition off. Measure voltage between ground and Pink/Black wire at No. 3 and 4 fuel tank solenoid valve wiring harness connectors (lower fuel tank rack assembly). Also, measure voltage of Pink/Black wire between ground and terminals No. 5 and 6 at upper fuel tank rack assembly Gray 8-pin connector (male side). If battery voltage is present at any terminal, repair short to power in Pink/Black wire and repeat step 1 to verify repair. If battery voltage is not present at any terminal, go to next step.
16. Isolate Upper & Lower Fuel Tank Rack Assemblies Tighten manual lock-down jack screw on No. 3 and 4 fuel tank solenoid valves to 80 INCH lbs. (9 N.m). Open bleed valve on fuel filler neck venting kit for 60 seconds. Close bleed valve. Observe system pressure on fuel filler neck venting kit pressure gauge. If pressure is zero psi, go to step 21. If pressure is not zero psi, go to next step.
17. Check Pink/Black Wire To No. 1 Fuel Tank Solenoid Ensure manual lock-down jack screw on No. 3 and 4 fuel tanks are still closed. Disconnect venting tank wiring harness. Open bleed valve on fuel filler neck venting kit and vent system pressure to zero psi. Close bleed valve. Remove upper fuel tank rack assembly. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Remove vapor vent box from upper fuel tank rack assembly. Disconnect No. 1 fuel tank solenoid valve connector. Reconnect upper fuel tank assembly Gray 8-pin connector, that was disconnected in step 1). Measure voltage between ground and Pink/Black wire at No. 1 fuel tank solenoid valve wiring harness connector. If battery voltage is present, repair short to power in Pink/Black wire and go to next step. If battery voltage is not present, mark No. 1 fuel tank solenoid valve as "MAY BE STUCK OPEN" and go to next step.
18. Check Pink/Black Wire To No. 2 Fuel Tank Solenoid Disconnect Black 2- connector for No. 2 fuel tank solenoid valve. Measure voltage between ground and Pink/Black wire at No. 2 fuel tank solenoid valve wiring harness connector. If battery voltage is present, repair short to power in Pink/Black wire and repeat step 1 to verify repair. If battery voltage is not present, mark No. 2 fuel tank solenoid valve as "MAY BE STUCK OPEN" and go to next step. NOTE: Ensure bleed valve on fuel filler neck venting kit. The following step will supply power to fuel tank solenoid valves for 30-60 seconds. If time expires, cycle start/stop button on NGS scan tool to restore power.
19. Check No. 1 Fuel Tank Solenoid Valve Operation Reconnect Black 2-pin connector for No. 2 fuel tank solenoid valve. Turn ignition on. Tighten manual lock-down jack screw on No. 1 fuel tank solenoid valve to 80 INCH lbs. (9 N.m). Using NGS scan tool, access OUTPUT TEST MODE. Command all outputs ON to activate solenoid. Observe pressure on fuel filler neck venting kit pressure gauge. If pressure is zero psi, mark No. 2 fuel tank solenoid valve as "STUCK OPEN". Replace solenoid valve after completing all test procedures. Go to next step. If pressure is not zero psi, mark No. 2 fuel tank solenoid valve as "GOOD" and go to next step.
20. Check No. 1 Fuel Tank Solenoid Valve Operation Turn ignition off. Open bleed valve on fuel filler neck venting kit and vent system pressure to zero psi. Close bleed valve. Open No. 1 fuel tank solenoid valve manual lock-down jack screw. (Scheme 8) Tighten manual lock-down jack screw on No. 2 fuel tank solenoid valve to 80 INCH lbs. (9 N.m). Disconnect Black 2-pin connector for No. 2 fuel tank solenoid valve. Reconnect Black 2-pin connector for No. 1 fuel tank solenoid valve. Turn ignition on. Using NGS scan tool, access OUTPUT TEST MODE. Command all outputs ON to activate solenoid. Observe pressure on fuel filler neck venting kit pressure gauge. If pressure is zero psi, mark No. 1 solenoid valve as "STUCK OPEN". Replace any lower fuel tank rack assembly solenoid valve that was marked "STUCK OPEN". Install lower fuel tank rack assembly (including vent box) and repeat step 1 to verify repair. If pressure is not zero psi, mark No. 1 solenoid valve as "GOOD". Restore vehicle and check system for normal operation.
21. Check For Stuck Open No. 3 Fuel Tank Solenoid Valve Turn ignition off. Open No. 3 fuel tank solenoid valve manual lock-down jack screw. (Scheme 8) Ensure No. 4 fuel tank solenoid valve manual lock-down jack screw is still closed. Open bleed valve on fuel filler neck venting kit for 60 seconds. Close bleed valve. Observe system pressure on fuel filler neck venting kit pressure gauge. If pressure is zero psi, mark No. 3 fuel tank solenoid valve as "GOOD" and go to next step. If pressure is not zero psi, mark No. 3 fuel tank solenoid valve as "STUCK OPEN" and go to next step.
22. Check For Stuck Open No. 4 Fuel Tank Solenoid Valve Turn ignition off. Tighten manual lock-down jack screw on No. 3 fuel tank solenoid valve to 80 INCH lbs. (9 N.m). Open bleed valve on fuel filler neck venting kit and vent system pressure to zero psi. Close bleed valve. Open No. 4 fuel tank solenoid valve manual lock-down jack screw. Open bleed valve on fuel filler neck venting kit and vent system pressure to zero psi. Close bleed valve. Observe system pressure on fuel filler neck venting kit pressure gauge. If pressure is zero psi, mark No. 4 fuel tank solenoid valve as "GOOD". Replace any upper fuel tank rack assembly solenoid valve that was marked "STUCK OPEN". Restore vehicle and check system for normal operation. If pressure is not zero psi, mark No. 4 fuel tank solenoid valve as "STUCK OPEN". Replace any fuel tank rack assembly solenoid valve that was marked "STUCK OPEN". Restore vehicle and check system for normal operation.

UNABLE TO VENT FUEL TANKS OR FUEL LINES (ECONOLINE)

Note. A DVOM, New Generation Star (007-00500) scan tool and Natural Gas Vehicle (NGV) Pressure Test and Vent Kit (134-00116) or equivalent test equipment are necessary to preform the following test procedures. Natural gas vehicle pressure test and vent kit consists of Rotunda Fuel Filler Neck Venting Kit (134-00117), Venting Hose (134-00118) and Grounding Cable (134-00121).

Visually inspect fuel system for damaged fuel tanks, solenoids, fuel lines/hoses, fuses, relays and loose or corroded connectors. If any faults are indicated, repair as necessary. If no faults are indicated and system will not vent, go to step 1 .

Note. Econoline maybe equipped with 3 fuel tanks. One tank located in front of the rear axle housing and 2 tanks located behind the rear drive axle housing. For testing purposes, fuel tank located in front of the rear axle housing will be referred to as fuel tank No. 1. The first fuel tank behind the rear axle housing will be referred to as fuel tank No. 2. The fuel tank located furthest behind the rear axle housing will be referred to as fuel tank No. 3.

1. Check No. 1 Fuel Tank Solenoid Valve Operation Turn ignition off. Insert grounding spike into earth. Connect Grounding Cable (134-00121) between grounding spike and backside of fuel fill valve at fuel line connection. see scheme 10 Connect Fuel Filler Neck Venting Kit (134-00116) to fuel fill valve. (Scheme 7) Connect Venting Hose (134-00118) to vent stack that allows natural gas to be vented outside of repair shop. Vent stack installation must be approved by local authorities. Close and tighten manual lock-down jack screw on No. 2 and 3 fuel tank solenoid valves (if equipped). Tighten jack screws 62-80 INCH lbs. (7-9 N.m). Open manual backflow valve on backside of fuel filler valve. see scheme 10 Open bleed valve on fuel filler neck venting kit for 60 seconds. Close bleed valve. Observe system pressure on fuel filler neck venting kit pressure gauge. If pressure is zero psi, go to step 3. If pressure is not zero psi, go to next step.
2. Check For Short To Power Disconnect 2-pin connector for No. 1 fuel tank solenoid valve. Measure voltage between ground and Pink/Black wire at No. 1 fuel tank solenoid valve wiring harness connector. If voltage is more than 10 volts, repair short to power in Pink/Black wire. If vehicle is equipped with No. 2 and 3 fuel tanks, go to step 6. If voltage is 10 volts or less, mark No. 1 fuel tank solenoid valve as "STUCK OPEN". Replace solenoid valve after completing all test procedures. If vehicle is equipped with No. 2 and 3 fuel tanks, go to step 6. If vehicle is not equipped with No. 2 and No. 3 fuel tanks, replace stuck open No. 1 fuel tank solenoid valve. Check system for normal operation. NOTE: The following step will supply power to fuel tank solenoid valves for 30-60 seconds. If time expires, cycle start/stop button on NGS scan tool to restore power.
3. Check No. 1 Fuel Tank Solenoid Valve Operation Turn ignition off. Reconnect 2-pin connector for No. 1 fuel tank solenoid valve. Turn ignition on. Using NGS scan tool, access OUTPUT TEST MODE. Command all outputs ON. Observe pressure on fuel filler neck venting kit pressure gauge. If pressure is zero psi, go to next step. If pressure is not zero psi, mark No. 1 fuel tank solenoid valve as "GOOD". If vehicle is equipped with No. 2 and 3 fuel tanks, go to step 6. If vehicle is not equipped with No. 2 and 3 fuel tanks, check system for normal operation.
4. Check For Open Circuit Turn ignition off. Disconnect 2-pin connector for No. 1 fuel tank solenoid valve. Turn ignition on. Using NGS scan tool, access OUTPUT TEST MODE. Command all outputs ON. Measure voltage between ground and Pink/Black wire at No. 1 fuel tank solenoid valve wiring harness connector. If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair open in Pink/Black wire. If vehicle is equipped with No. 2 and 3 fuel tanks, go to step 6. If vehicle is not equipped with No. 2 and 3 fuel tanks, check system for normal operation.
5. Check Ground To No. 1 Fuel Tank Solenoid Valve Turn ignition off. Using ohmmeter, measure resistance between ground and Black wire at No. 1 fuel tank solenoid wiring harness connector. If resistance is less than 5 ohms, mark No. 1 solenoid as "STUCK CLOSED". Replace solenoid after completing all test procedures. If vehicle is equipped with No. 2 and 3 fuel tanks, go to next step. If vehicle is not equipped with No. 2 and No. 3 fuel tanks, replace solenoid valve for No. 1 fuel tank. Go to next step. If resistance is 5 ohms or more repair open in Black wire between ground and solenoid valve. If vehicle is equipped with No. 2 and 3 fuel tanks, go to next step. If vehicle is not equipped with No. 2 and 3 fuel tanks, check system for normal operation.
6. Check No. 3 Fuel Tank Solenoid Reconnect 2-pin connector for No. 1 fuel tank solenoid valve. Close No. 1 fuel tank solenoid manual lock-down jack screw and tighten jack screw 62-80 INCH lbs. (7-9 N.m). (Scheme 8) Open No. 3 fuel tank solenoid manual lock-down jack screw. Open bleed valve on fuel filler neck venting kit for 60 seconds. Close bleed valve. Observe system pressure on fuel filler neck venting kit pressure gauge. If pressure is zero psi, go to step 8. If pressure is not zero psi, go to next step.
7. Check For Short To Power Disconnect 2-pin connector for No. 3 fuel tank solenoid valve. Measure voltage between ground and Pink/Black wire at No. 3 fuel tank wiring harness connector. If voltage is more than 10 volts, repair short to power in Pink/Black wire. Go to step 11. If voltage is 10 volts or less, mark No. 3 fuel tank solenoid valve as "STUCK OPEN" and go to step 11. NOTE: The following step will supply power to fuel tank solenoid valves for 30-60 seconds. If time expires, cycle start/stop button on NGS scan tool to restore power.
8. Check No. 2 Fuel Tank Solenoid Operation Reconnect 2-pin connector for No. 2 fuel tank solenoid valve. Turn ignition on. Using NGS scan tool, access OUTPUT TEST MODE. Command all outputs ON. Observe pressure on fuel filler neck venting kit pressure gauge. If pressure is zero psi, go to next step. If pressure is not zero psi, mark No. 3 fuel tank solenoid valve as "GOOD" and go to step 11.
9. Check For Open Circuit Turn ignition off. Disconnect 2-pin connector for No. 3 fuel tank solenoid valve. Turn ignition on. Using NGS scan tool, access OUTPUT TEST MODE. Command all outputs ON. Measure voltage between ground and Pink/Black wire at No. 3 fuel tank solenoid wiring harness connector. If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair open in Pink/Black wire and go to step 11.
10. Check Ground Circuit Turn ignition off. Measure resistance between ground and Black wire at No. 3 fuel tank wiring harness connector. If resistance is more than 5 ohms, repair open in Black wire and go to next step. If resistance is 5 ohms or less, mark No. 3 fuel tank solenoid valve as "STUCK CLOSED" and go to next step.
11. Check No. 2 Fuel Tank Solenoid Reconnect 2-pin connector for No. 3 fuel tank solenoid valve. Close No. 3 fuel tank solenoid valve manual lock-down jack screw. (Scheme 8) Tighten manual lock-down jack screw 62-80 INCH lbs. (7-9 N.m). Open No. 2 fuel tank solenoid valve manual lock-down jack screw. Open bleed valve on fuel filler neck venting kit for 60 seconds. Close bleed valve. Observe system pressure on fuel filler neck venting kit pressure gauge. If pressure is zero psi, go to step 13. If pressure is not zero psi, go to next step.
12. Check For Short To Power Disconnect 2-pin connector for No. 2 fuel tank solenoid valve. Measure voltage between ground and Pink/Black wire at No. 2 fuel tank solenoid valve wiring harness connector. If voltage is more than 10 volts, repair short to power in Pink/Black wire. Replace any solenoid valve that was marked "STUCK CLOSED" or "STUCK OPEN". Check system for normal operation. If voltage is 10 volts or less, mark No. 2 fuel tank solenoid valve as "STUCK OPEN". Replace any solenoid valve that was marked "STUCK CLOSED" or "STUCK OPEN". Check system for normal operation. NOTE: The following step will supply power to fuel tank solenoid valves for 30-60 seconds. If time expires, cycle start/stop button on NGS scan tool to restore power.
13. Check No. 2 Fuel Tank Solenoid Operation Reconnect 2-pin connector for No. 2 fuel tank solenoid valve. Turn ignition on. Using NGS scan tool, access OUTPUT TEST MODE. Command all outputs ON. Observe pressure on fuel filler neck venting kit pressure gauge. If pressure is zero psi, go to next step. If pressure is not zero psi, mark No. 2 fuel tank solenoid valve as "GOOD". Replace any solenoid valve that was marked "STUCK CLOSED" or "STUCK OPEN". Check system for normal operation.
14. Check For Open Circuit Turn ignition off. Disconnect 2-pin connector for No. 2 fuel tank solenoid valve. Turn ignition on. Using NGS scan tool, access OUTPUT TEST MODE. Command all outputs ON. Measure voltage between ground and Pink/Black wire at No. 2 fuel tank solenoid valve wiring harness connector. If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair open in Pink/Black wire. Replace any solenoid valve that was marked "STUCK CLOSED" or "STUCK OPEN". Check system for normal operation.
15. Check Ground Circuit Turn ignition off. Measure resistance between ground and Black wire at for No. 2 fuel tank solenoid valve wiring harness connector. If resistance is more than 5 ohms, repair open in Black wire. Replace any solenoid valve that was marked "STUCK CLOSED" or "STUCK OPEN". Check system for normal operation. If resistance is 5 ohms or less, mark No. 2 fuel tank solenoid as "STUCK CLOSED". Replace any solenoid valve that was marked "STUCK CLOSED" or "STUCK OPEN". Check system for normal operation.

UNABLE TO VENT FUEL TANKS OR FUEL LINES (PICKUP)

Note. A DVOM, New Generation Star (007-00500) scan tool and Natural Gas Vehicle (NGV) Pressure Test and Vent Kit (134-00116) or equivalent test equipment are necessary to preform the following test procedures. Natural gas vehicle pressure test and vent kit consists of Rotunda Fuel Filler Neck Venting Kit (134-00117), Venting Hose (134-00118) and Grounding Cable (134-00121).

Visually inspect fuel system for damaged fuel tanks, solenoids, fuel lines/hoses, fuses, relays and loose or corroded connectors. If any faults are indicated, repair as necessary. If no faults are indicated and system will not vent, go to step 1 .

Note. Battery must be fully charged to perform solenoid diagnostics. Whenever connecting vent tool, ensure vent tool bleed valve is closed.

1. Check Rear In-Bed Fuel Tank Solenoid Operation Turn ignition off. Insert grounding spike into earth. Connect Grounding Cable (134-00121) between grounding spike and backside of fuel fill valve at fuel line connection. see scheme 10 Connect Fuel Filler Neck Venting Kit (134-00116) to fuel fill valve. (Scheme 7) Connect Venting Hose (134-00118) to vent stack that allows natural gas to be vented outside of repair shop. Vent stack installation must be approved by local authorities. Close and tighten manual lock-down jack screw on forward in-bed fuel tank solenoid valve 62-80 INCH lbs. (7-9 N.m). Close and tighten manual lock-down jack screw on mid fuel tank (if equipped) solenoid valve 62-80 INCH lbs. (7-9 N.m). Open manual backflow valve on backside of fuel filler valve. Open bleed valve on fuel filler neck venting kit for 60 seconds. Close bleed valve. Observe system pressure on fuel filler neck venting kit pressure gauge. If pressure is zero psi, go to step 3. If pressure is not zero psi, go to next step.
2. Check For Short To Power Disconnect 2-pin connector for rear in-bed fuel tank solenoid valve. Measure voltage between ground and Pink/Black wire at rear in-bed fuel tank solenoid valve wiring harness connector. If voltage is more than 10 volts, repair short to power in Pink/Black wire. If voltage is 10 volts or less, mark rear in-bed fuel tank solenoid valve as "STUCK OPEN". Replace solenoid valve after completing all test procedures. Go to step 6. NOTE: The following step will supply power to fuel tank solenoid valves for 30-60 seconds. If time expires, cycle start/stop button on NGS scan tool to restore power.
3. Check Rear In-Bed Fuel Tank Solenoid Valve Operation Turn ignition off. Reconnect 2-pin connector for rear in-bed fuel tank solenoid valve. Turn ignition on. Using NGS scan tool, access OUTPUT TEST MODE. Command all outputs ON. Observe pressure on fuel filler neck venting kit pressure gauge. If pressure is zero psi, go to next step. If pressure is not zero psi, mark rear in-bed fuel tank solenoid valve as "GOOD" and go to step 6.
4. Check For Open Circuit Turn ignition off. Disconnect 2-pin connector for rear in-bed fuel tank solenoid valve. Turn ignition on. Using NGS scan tool, access OUTPUT TEST MODE. Command all outputs ON. Measure voltage between ground and Pink/Black wire at rear in-bed fuel tank solenoid valve wiring harness connector. If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair open in Pink/Black wire and go to step 6.
5. Check Ground To Rear In-Bed Fuel Tank Solenoid Valve Turn ignition off. Using ohmmeter, measure resistance between ground and Black wire at rear in-bed fuel tank solenoid valve wiring harness connector. If resistance is less than 5 ohms, mark rear in-bed fuel tank solenoid valve as "STUCK CLOSED". Replace solenoid valve after completing all test procedures. Go to next step. If resistance is 5 ohms or more, repair open in Black wire between ground and solenoid valve. Go to next step.
6. Check Forward In-Bed Fuel Tank Solenoid Valve Reconnect 2-pin connector for rear in-bed fuel tank solenoid valve. Close rear in-bed fuel tank solenoid valve manual lock-down jack screw and tighten jack screw 62-80 INCH lbs. (7-9 N.m). (Scheme 8) Open forward in-bed fuel tank solenoid valve manual lock-down jack screw. Open bleed valve on fuel filler neck venting kit for 60 seconds. Close bleed valve. Observe system pressure on fuel filler neck venting kit pressure gauge. If pressure is zero psi, go to step 8. If pressure is not zero psi, go to next step.
7. Check For Short To Power Disconnect 2-pin connector for forward in-bed fuel tank solenoid valve. Measure voltage between ground and Pink/Black wire at forward in-bed fuel tank wiring harness connector. If voltage is more than 10 volts, repair short to power in Pink/Black wire. If vehicle is equipped with a middle fuel tank, go to step 11. If vehicle is not equipped with a middle fuel tank, replace any solenoid valve that was marked "STUCK CLOSED" or "STUCK OPEN". Check system for normal operation. If voltage is 10 volts or less, mark forward in-bed fuel tank solenoid valve as "STUCK OPEN". If vehicle is equipped with a middle fuel tank, go to step 11. If vehicle is not equipped with a middle fuel tank, replace any solenoid valve that was marked as "STUCK CLOSED" or "STUCK OPEN". Check system for normal operation. NOTE: The following step will supply power to fuel tank solenoid valves for 30-60 seconds. If time expires, cycle start/stop button on NGS scan tool to restore power.
8. Check Forward In-Bed Fuel Tank Solenoid Operation Reconnect 2-pin connector for forward in-bed fuel tank solenoid valve. Turn ignition on. Using NGS scan tool, access OUTPUT TEST MODE. Command all outputs ON. Observe pressure on fuel filler neck venting kit pressure gauge. If pressure is zero psi, go to next step. If pressure is not zero psi, mark forward in-bed fuel tank solenoid valve as "GOOD". If vehicle is equipped with a middle fuel tank, go to step 11. If vehicle is not equipped with a middle fuel tank, replace any solenoid valve that was marked "STUCK CLOSED" or "STUCK OPEN". Check system for normal operation.
9. Check For Open Circuit Turn ignition off. Disconnect 2-pin connector for forward in-bed fuel tank solenoid valve. Turn ignition on. Using NGS scan tool, access OUTPUT TEST MODE. Command all outputs ON. Measure voltage between ground and Pink/Black wire at forward in-bed fuel tank solenoid valve wiring harness connector. If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair open in Pink/Black wire. If vehicle is equipped with a middle fuel tank, go to step 11. If vehicle is not equipped with a middle fuel tank, replace any solenoid valve that was marked "STUCK CLOSED" or "STUCK OPEN". Check system for normal operation.
10. Check Ground Circuit Turn ignition off. Measure resistance between ground and Black wire at forward in-bed fuel tank solenoid valve wiring harness connector. If resistance is more than 5 ohms, repair open in Black wire. If vehicle is equipped with a middle fuel tank, go to step 11. If vehicle is not equipped with a middle fuel tank, replace any solenoid valves that are marked "STUCK CLOSED" or "STUCK OPEN". Check system for normal operation. If resistance is 5 ohms or less, mark forward in-bed fuel tank solenoid valve as "STUCK CLOSED". If vehicle is equipped with a middle fuel tank, go to step 11. If vehicle is not equipped with a middle fuel tank, replace any solenoid valve that was marked "STUCK CLOSED" or "STUCK OPEN". Check system for normal operation.
11. Check Middle Fuel Tank Solenoid Valve Reconnect 2-pin connector for forward in-bed fuel tank solenoid valve. Close forward and rear in-bed fuel tank solenoid valve manual lock-down jack screws. (Scheme 8) Tighten manual lock-down jack screws 62-80 INCH lbs. (7-9 N.m). Open middle fuel tank solenoid valve manual lock-down jack screw. Open bleed valve on fuel filler neck venting kit for 60 seconds. Close bleed valve. Observe system pressure on fuel filler neck venting kit pressure gauge. If pressure is zero psi, go to step 13. If pressure is not zero psi, go to next step.
12. Check For Short To Power Disconnect 2-pin connector for middle fuel tank solenoid valve. Measure voltage between ground and Pink/Black wire at middle fuel tank solenoid valve wiring harness connector. If voltage is more than 10 volts, repair short to power in Pink/Black wire. Replace any solenoid valve that was marked "STUCK CLOSED" or "STUCK OPEN". Check system for normal operation. If voltage is 10 volts or less, mark forward in-bed fuel tank solenoid valve as "STUCK OPEN". Replace any solenoid valve that was marked "STUCK CLOSED" or "STUCK OPEN". Check system for normal operation. NOTE: The following step will supply power to fuel tank solenoid valves for 30-60 seconds. If time expires, cycle start/stop button on NGS scan tool to restore power.
13. Check Middle Fuel Tank Solenoid Operation Reconnect 2-pin connector for middle fuel tank solenoid valve. Turn ignition on. Using NGS scan tool, access OUTPUT TEST MODE. Command all outputs ON. Observe pressure on fuel filler neck venting kit pressure gauge. If pressure is zero psi, go to next step. If pressure is not zero psi, mark middle fuel tank solenoid valve as "GOOD". Replace any solenoid valve that was marked "STUCK CLOSED" or "STUCK OPEN". Check system for normal operation.
14. Check For Open Circuit Turn ignition off. Disconnect 2-pin connector for middle fuel tank solenoid valve. Turn ignition on. Using NGS scan tool, access OUTPUT TEST MODE. Command all outputs ON. Measure voltage between ground and Pink/Black wire at middle fuel tank solenoid valve wiring harness connector. If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair open in Pink/Black wire. Replace any solenoid valve that was marked "STUCK CLOSED" or "STUCK OPEN". Check system for normal operation.
15. Check Ground Circuit Turn ignition off. Measure resistance between ground and Black wire at middle fuel tank wiring harness connector. If resistance is more than 5 ohms, repair open in Black wire. Replace any solenoid valve that was marked "STUCK CLOSED" or "STUCK OPEN". Check system for normal operation. If resistance is 5 ohms or less, mark middle fuel tank solenoid valve as "STUCK CLOSED". Replace any solenoid valve that was marked "STUCK CLOSED" or "STUCK OPEN". Check system for normal operation.

IDLE AIR CONTROL SOLENOID

Solenoid is by-pass air type. Ensure ignition is off. Disconnect IAC solenoid harness connector. Measure resistance between IAC solenoid connector terminals. Solenoid has diode and resistance will be infinite if voltmeter is hooked up wrong. If resistance is not 6-13 ohms, replace solenoid. If resistance is 6-13 ohms, IAC solenoid is okay. See TEST KE under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article for additional testing and specifications.

IGNITION SYSTEMS

Note. For additional information and descriptions, see IGNITION SYSTEMS in THEORY & OPERATION - ECC-V article

Faults in ignition system may set a Diagnostic Trouble Code. See QUICK TEST in SELF-DIAGNOSTICS - EEC-V article. If any DTCs are present, perform appropriate system test. If no DTCs are present, check secondary ignition system. See TEST JB under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.

EXHAUST CATALYST

1. Disable secondary air injection system. Run engine at 2500 RPM for 2 minutes. Turn ignition off. Disconnect and ground one spark plug wire or disconnect one ignition coil for coil on plug applications.
2. Start engine and run at 1000 RPM. Disconnect IAC valve. Using an infrared temperature probe, measure surface temperature at catalytic converter inlet and outlet. Outlet temperature should be at least 50°F (28°C) greater than inlet temperature. Replace catalytic converter if necessary. Reconnect ignition system, IAC valve and secondary air injection.

SECONDARY AIR INJECTION

Faults in Secondary Air Injection (AIR) system should set a Diagnostic Trouble Code. See QUICK TEST in SELF-DIAGNOSTICS - EEC-V article. If any DTCs are present, perform appropriate system test. If no DTCs are present, check AIR system. See TEST HM under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.

EGR Valve

1. Ensure all vacuum hoses are correctly routed and securely attached. Replace any crimped or broken hoses. Ensure there is less than one in. Hg vacuum to EGR valve at idle with engine at normal operating temperature.
2. Install tachometer. Disconnect Idle Air Control (IAC) wiring harness connector. Remove and plug vacuum hose at EGR valve. Start engine. Idle in Neutral. Note idle speed. Using hand vacuum pump, slowly apply 5-10 in. Hg vacuum to EGR valve. When vacuum is fully applied, engine should do one or more of the following: Engine should stall. Idle speed should drop more than 100 RPM. Idle speed should return to normal when vacuum is released.
3. Service or replace EGR valve if engine does not stall or idle speed does not respond as specified. Reconnect IAC harness connector. Unplug and reconnect vacuum hose at EGR valve. For additional EGR system testing, go to TEST HE under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.

Turn ignition off. Disconnect EVR solenoid wiring harness connector. Measure resistance between EVR solenoid terminals. If resistance is not 26-40 ohms, replace EVR solenoid. For additional EGR system testing, go to TEST HE under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.

FUEL EVAPORATION

Note. For testing of any evaporative emission system component not found here, see CIRCUIT TEST HX under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.

Turn ignition off. Disconnect CV solenoid wiring harness connector. Measure resistance between CV solenoid terminals. If resistance is not 48-65 ohms, replace CV solenoid and repeat QUICK TEST. If resistance is 48-65 ohms, solenoid is okay. If fault is still present, go to CIRCUIT TEST HX in SELF-DIAGNOSTICS - EEC-V article.

EVAP Canister (All Models)

There are no moving parts in canister. Check for loose, missing, cracked or broken connections and parts. Repair or replace canister as necessary. There should be no liquid in canister.

POSITIVE CRANKCASE VENTILATION (PCV)

1. Check PCV Valve Remove PCV valve. Shake valve and listen for rattle. If PCV valve rattles when shaken, go to next step. Replace PCV valve if it does not rattle when shaken.
2. Check PCV System Start engine and warm to normal operating temperature. Disconnect hose from remote air cleaner or outlet tube. Place a stiff piece of paper over end of hose. If vacuum from hose does not hold paper in place for one minute, repair clogged or leaking hose as necessary. If vacuum from hose holds paper in place for one minute, PCV system is okay and testing is complete.

See also:
• FUEL PRESSURE SPECIFICATIONS
• INERTIA FUEL SHUTOFF (IFS) SWITCH LOCATION TABLE (CARS)
• IDLE AIR CONTROL SOLENOID
• RELAYS