Engine Controls - System/component Tests - 7.3L Diesel: Other Ford RV Cutaway E350

Mechanical Fuel Pump

Note. For fuel pressure specifications, see FUEL PRESSURE SPECIFICATIONS article.

1. Connect Engine Pressure Test Kit (014-00761) and Adapter (014-00931-3) to Schrader valve. Schrader valve is part of fuel regulator block. Connect fuel line between adapter and 0-160 psi (0-1103 kPa) gauge (No. 6) at engine pressure tester. see scheme 6
2. Crank engine (minimum of 100 RPM) for 20 seconds and observe fuel pressure gauge. If fuel pressure is as specified, fuel pressure is okay. If fuel pressure is less than specified, replace fuel filter and retest. Cycle ignition switch several times to purge air from system. If fuel pressure is still low, check the following: Check fuel level in gas tank. Disassemble, inspect and clean fuel pressure regulator valve. (Scheme 142) Check for bent or damaged fuel lines. Check for blockage at fuel pick-up tube. Check for loose fuel line on suction side of fuel system. If fuel line is tight, replace fuel pump and retest.

Electric Fuel Pump

Note. For fuel pressure specifications, see FUEL PRESSURE SPECIFICATIONS article.

1. Ensure fuel tank has fuel. Ensure fuel pump has power and ground. With ignition on, battery voltage should be present at fuel pump for about 20 seconds. If voltage is as specified, go to next step. If voltage is not as specified, perform CIRCUIT TEST FK in «TESTS W/CODES - 7.3L DIESEL»(ref-24260) article.
2. Remove cover and 1/8" pipe plug from top rear of left cylinder head. Install fuel pressure gauge. Check fuel pressure with engine cranking or running. If fuel pressure is not as specified, go to FUEL PUMP PRESSURE TEST under «ENGINE PERFORMANCE DIAGNOSIS»(ref-24265-S41699597992001010400000) .

Scheme 142

Right Cylinder Head Check

1. Perform step 3) under «CHECK PARAMETER IDENTIFICATION (PID) DURING CRANKING»(ref-24265-S23525169982001010400000) (if not already completed). Remove high pressure hose from right cylinder head. Using Fuel/Oil/Turbo Protector Cap Set (T94T-9395-AH), install appropriate cap on high pressure hose fitting on cylinder head. Using Oil High Pressure Leakage Test Adapter Set (D94T-6600-A), install plug into high pressure hose. WARNING: In the following step, engine may start.
2. Install ICP/EBP Adapter Cable (D94T-50-A) between ICP sensor and sensor wiring harness connector. Connect a DVOM between SIG RTN circuit (Black wire) and ICP Signal circuit (Green wire) at ICP/EBP adapter cable. Observe DVOM and crank engine. Voltage reading should be 1-4 volts.
3. If engine starts, or if ICP PID reading indicates 500 psi (3448 kPa) or more, an injection control pressure oil leak exists in right cylinder head. Inspect fuel system for oil contamination.
4. If no oil is present in fuel system, remove cap and plug, and reinstall high pressure hose to right cylinder head. Remove right valve cover. Crank engine, and inspect injector body and injector bore area for oil leakage. Repair as necessary. If engine does not start, or ICP PID is still less than 500 psi (3448 kPa), perform LEFT CYLINDER HEAD CHECK.

Left Cylinder Head Check

1. Remove high pressure hose from left cylinder head. Using fuel/oil/turbo protector cap set, install appropriate cap on high pressure hose fitting on cylinder head. Using oil high pressure leakage test adapter set, install ICP adapter into high pressure hose. (Scheme 143)
2. Remove ICP sensor and install sensor in end of ICP adapter. Install ICP/EBP Adapter Cable (D94T-50-A) between ICP sensor and sensor wiring harness connector. Connect a DVOM between SIG RTN circuit (Black wire) and ICP Signal circuit (Green wire) at ICP/EBP adapter cable. Observe DVOM and crank engine. Voltage reading should be 1-4 volts. WARNING: In the following step, engine may start.
3. If engine starts, or if ICP PID reading indicates 500 psi (3448 kPa) or more, an injection control pressure oil leak exists in left cylinder head. Reconnect high pressure hose to left cylinder head. Remove left valve cover. Crank engine, and inspect injector body and injector bore area for oil leakage. Repair as necessary.
4. If injection control pressure is still low after completing both right and left cylinder head checks and no oil leaks have been found, remove high pressure hose from right and left cylinder heads. Using fuel/oil/turbo protector cap set, install appropriate cap on high pressure hose fitting on each cylinder head.
5. Using oil high pressure leakage test adapter set, install plug into each high pressure hose. Both high pressure lines should now be blocked off. Using scan tool, observe ICP PID reading while cranking engine.
6. If PID reading is still less than 500 psi (3448 kPa), replace Injection Pressure Regulator (ICP) with a known good ICP and retest. If PID reading is now 500 psi (3448 kPa) or more, replace ICP. If PID reading is still less than 500 psi (3448 kPa), high pressure pump or high pressure pump drive gear is faulty. Repair as necessary.

Scheme 143

Check Air Filter

Inspect air cleaner assembly for proper installation. Ensure air ducting is not blocked or collapsed. Inspect filter minder on filter housing to ensure intake restriction is below Red marks. Replace filter as necessary.

Note. For fuel pressure specifications, see FUEL PRESSURE SPECIFICATIONS article.

1. Ensure fuel tank has fuel. Ensure fuel pump has power and ground. With ignition on, battery voltage should be present at fuel pump for about 20 seconds. If voltage is as specified, go to next step. If voltage is not as specified, perform CIRCUIT TEST FK in «TESTS W/CODES - 7.3L DIESEL»(ref-24260) article.
2. Remove fuel line to inlet side of fuel pump. Install Fuel Pressure Adapter (014-00931-2) between fuel inlet line and fuel pump. Connect fuel pressure adapter to vacuum gauge (0-30 in. Hg) of Engine Pressure Tester (014-00761). see scheme 6
3. Start engine and allow it to idle. Observe vacuum gauge and briefly raise engine speed to 3500 RPM. If vacuum is 6 in. Hg or less, no restriction exist at this time. Go to next step. If vacuum is more than 6 in. Hg, check for blockage between pump and fuel tank. Repair as necessary.
4. Remove fuel pressure adapter and reconnect fuel line to inlet side of fuel pump. Remove fuel line from outlet side of fuel pump. Install fuel pressure adapter between fuel outlet line and fuel pump. Connect fuel pressure adapter to 0-160 psi (0-1103 kPa) gauge (No. 6) at engine pressure tester. see scheme 6
5. Start engine and allow it to idle. Observe fuel pressure gauge and briefly raise engine speed to 3500 RPM. If fuel pressure is as specified, fuel pressure is okay. Go to next step. If fuel pressure is not as specified, check fuel regulator valve for sticking or debris. (Scheme 144) Repair as necessary and retest. If fuel regulator valve is okay, replace fuel pump and retest.
6. Remove cover and 1/8" pipe plug from top rear of left cylinder head. Install fuel pressure gauge. Start engine. Check fuel pressure with full load on engine. DO NOT brake torque engine for more than 10 seconds. If fuel pressure is as specified, go to next step. If fuel pressure is not as specified, replace fuel filter and retest. If fuel pressure is still low, replace left fuel check valve. Check valve is located in front of left cylinder head between fuel inlet line and cylinder head.
7. Remove 1/8" pipe plug from top front of right cylinder head. It may be necessary to remove generator and bracket to access pipe plug. Install fuel pressure gauge. Start engine. Check fuel pressure with full load on engine. DO NOT brake torque engine for more than 10 seconds. If fuel pressure is as specified, fuel pressure is okay. If fuel pressure is not as specified, replace right fuel check valve. Check valve is located in rear of right cylinder head between fuel inlet line and cylinder head.

Scheme 144

With Mechanical Fuel Pump

1. Disconnect fuel return hose at fuel filter. Install a clear fuel hose between fuel return hose and fuel return hose fitting at fuel filter. Loop hose at a point higher than fuel filter. (Scheme 145) While observing fuel line, start and run engine for about 5 minutes. Fuel should be free of air.
2. If fuel is foamy, check for an air leak in fuel lines between fuel pump and fuel tank. Repair as necessary. If no fuel flow exists, remove fuel regulator block, taking care not to damage "O" ring. Inspect fuel return orifice screen for debris. Clean as necessary. (Scheme 146)

Scheme 145

Scheme 146

Oil Aeration/Poor Idle

1. Connect New Generation Star (NGS) scan tool to Data Link Connector (DLC). Turn A/C off. Using scan tool, access ICP PID from PID/DATA monitor menu. See ADDITIONAL SYSTEM FUNCTIONS in «TESTS W/CODES - 7.3L DIESEL»(ref-24260) article.
2. Start engine and raise engine speed to 3400 RPM for 3 minutes. ICP PID reading should be 750-1250 psi (5171-8619 kPa). If PID reading is not 750-1250 psi (5171-8619 kPa), change oil and retest.

Low Idle Stability (ICP Pressure)

1. Ensure engine is at normal operating temperature. Using scan tool, access ICP PID from PID/DATA monitor menu. Start engine and allow it to idle.
2. Check PID value. See ICP PID VALUES table. If PID reading is not as specified, or idle does not stabilize, disconnect ICP sensor. Sensor is located at top left side of engine.
3. If idle is now stabilized, fault is in ICP sensor circuit. Perform CIRCUIT TEST DD in «TESTS W/CODES - 7.3L DIESEL»(ref-24260) article. If idle still does not stabilize, replace Injection Pressure Regulator (IPR) and retest.

ICP PID VALUES

CHECK CYLINDER PERFORMANCE

If KOER CYLINDER CONTRIBUTION SELF-TEST under QUICK TEST in TESTS W/CODES - 7.3L DIESEL article has been successfully completed previously, go to CHECK FOR EXHAUST RESTRICTION . If KOER CYLINDER CONTRIBUTION SELF-TEST has not been completed, perform KOER CYLINDER CONTRIBUTION SELF-TEST. Possible causes for failing this test are

1. Broken compression rings.
2. Burnt or bent valve.
3. Bent push rods.
4. Bent connecting rods.
5. Damaged rocker arms.
6. Faulty fuel injector assembly.