Engine Controls - System & Component Tests - 7.3L Diesel: Diagnosis Ford Pickup F350

HARD START/NO-START DIAGNOSIS

Note. Repair each problem detected before going on to the next step. If repair corrects the original complaint, it will not be necessary to proceed to the next step or diagnostic procedure. However, if complaint is not corrected, continue with the testing until complaint is corrected.

Diagnostic Aids

Perform visual inspection to check general engine condition and look for obvious causes of hard start or no-start conditions. Possible causes of a hard or no-start condition are

1. Loose or leaking fuel supply lines could cause system to lose prime.
2. Kinked or blocked fuel supply lines.
3. Loose or damaged Camshaft Position (CMP) sensor and Injection

Checking engine oil helps determine if there is enough engine oil to operate fuel injectors. If there is little or no oil in crankcase, injectors will not operate.

1. Ensure vehicle is on level ground. Check engine oil. If oil is overfilled, engine may have been incorrectly serviced, or fuel is diluted with engine oil and filling crankcase. Repair as necessary.
2. Inspect oil color. A milky White color indicates possible coolant contamination. Determine cause and repair as necessary. If oil level is low, top off oil. Ensure oil is correct type and viscosity.
3. Remove plug in top of oil reservoir and check oil level. If oil level is within 1" (25.4 mm) of fill hole, level is okay. If oil level is not within 1" (25.4 mm) of fill hole, top off fluid. Attempt to start vehicle. If vehicle starts, determine cause of low oil level and repair as necessary.

This is a visual inspection to determine if an air intake or exhaust restriction is contributing to a hard or no-start condition. If engine does not start and a air intake or exhaust restriction exists, a large amount of Black/Blue smoke will exist while cranking engine.

1. Inspect air cleaner assembly for proper installation. Ensure air ducting is not blocked or collapsed. Inspect filter minder on filter housing to assure intake restriction is below Red marks. Replace filter as necessary.
2. Crank engine and inspect turbocharger exhaust backpressure butterfly bellcrank. Ensure bellcrank is not closed. When tang is against the stop, valve is fully open. (Scheme 404)

Scheme 404

Purpose of this test is to see if fuel system is getting sufficient clean fuel to start and run engine.

1. Connect a hose to fuel drain line at bottom of fuel filter housing. Place other end of hose into a suitable container. Open fuel drain. Crank engine and observe fuel. Fuel flow should be a steady stream.
2. Check WATER IN FUEL warning light indicator. If warning light is on, fuel is contaminated with water. Service fuel system as necessary. If engine oil is present in fuel, injector "O" ring(s) may be defective. Perform «INJECTION CONTROL PRESSURE TESTS»(ref-23714-S07747705732001010300000) . Repair oil leaks as necessary.

Note. Some sediment and water may be present in fuel sample if fuel filter has not been serviced for a prolonged period of time. A second sample may be necessary to determine fuel quality.

TANDEM FUEL PUMP PRESSURE TEST

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. (Scheme 408)
2. Crank engine (minimum of 100 RPM) for 20 seconds and observe fuel pressure gauge. If fuel pressure is 20 psi (138 kPa) or more, fuel pressure is okay. If fuel pressure is less than 20 psi (138 kPa), 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 405) 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.

Scheme 405

Purpose of this test is to verify Powertrain Control Module (PCM) power-up during cranking. Lack of power at PCM during cranking can cause a no-start condition and a fault code loss.

1. Check VPWR PID Connect New Generation Star (NGS) tester to Data Link Connector (DLC). Using scan tester, access VPWR PID from PID/DATA monitor menu. See procedures under ADDITIONAL SYSTEM FUNCTIONS in the «TESTS W/CODES - 7.3L DIESEL»(ref-23600) article. Crank engine while monitoring PID reading. If PID reading indicates more than 7 volts, go to next step. If PID reading indicates 7 volts or less, check charging circuit, power and ground circuits. See CIRCUIT TEST A in the «TESTS W/CODES - 7.3L DIESEL»(ref-23600) article.
2. Check RPM PID Using scan tester, access RPM PID from PID/DATA monitor menu. Crank engine while monitoring PID reading. If PID reading indicates more than 100 RPM, go to next step. If PID reading indicates 100 RPM or less, check Camshaft Position (CMP) sensor circuit. See CIRCUIT TEST G in the «TESTS W/CODES - 7.3L DIESEL»(ref-23600) article.
3. Check Fuel Pulse Width Using scan tester, access FUEL PW PID from PID/DATA monitor menu. Crank engine while monitoring PID reading. If PID reading indicates 1-6 milliseconds, go to next step. If PID reading does not indicate 1-6 milliseconds, injectors are not receiving Fuel Delivery Command Signal (FDCS). For testing, see CIRCUIT TEST G in the «TESTS W/CODES - 7.3L DIESEL»(ref-23600) article.
4. Check ICP PID Using scan tester, access ICP PID from PID/DATA monitor menu. Crank engine while monitoring PID reading. If PID reading indicates 500 psi (3448 kPa) or more, go to «GLOW PLUG SYSTEM OPERATION»(ref-23714-S01482839092001010300000) . If PID reading indicates less than 500 psi (3448 kPa), injectors are not being energized because of insufficient pressure. Perform «INJECTION CONTROL PRESSURE TEST»(ref-23714-S07747705732001010300000) .

Removing Injection Control Pressure (ICP) sensor and inspecting level in oil rail will determine if oil is being supplied to rail. Removing inspection plug in top of reservoir will help determine if reservoir is full. A reservoir that drains back after engine has not been operated for a long period of time can cause a hard start condition.

Insufficient glow plug "On" time will not allow enough heat to accumulate in combustion chamber resulting in a hard start condition. If glow plug system "On" time is insufficient, probable cause is a faulty wiring harness connector, bad ground connection or defective glow plug relay. If glow plug resistance to ground is high, probable cause is an open circuit in Under Valve Cover (UVC) wiring harness or an open glow plug.

Scheme 406

1. Connect a DVOM between ground and Black/Orange wire at glow plug relay. (Scheme 406) Turn ignition on. If battery voltage is present, go to next step. If battery voltage is not present, locate and repair open circuit in Black/Orange wire between glow plug relay and starter relay.
2. Turn ignition off. Connect DVOM between ground and Brown wire at glow plug relay. Turn ignition on and note how long is takes for glow plug relay to energize and de-energize ("On" time). Relay will make a loud click noise when it energizes. If relay "On" time is not as specified, replace relay. See «GLOW PLUG RELAY SPECIFICATIONS»(ref-23714-S38376078642002011100000) table. If "On" time is as specified, go to next step. GLOW PLUG RELAY SPECIFICATIONS Engine Oil Temperature: °F (°C) "On" Time: Seconds 14 (-10) 120 60 (16) 60 200 (93) 35 234 (112) 0 NOTE: Each valve cover gasket has 2 fuel injector connectors that are part of the gasket. Each connector is responsible for 2 fuel injectors. If connector is faulty, replace valve cover gasket.
3. Turn ignition off. Disconnect all (4) injector connectors at valve cover gaskets. Install Glow Plug Injector Adapter (014-00935) to any injector connector at valve cover gasket. (Scheme 407) NOTE: If all injector connectors are not disconnected at both valve cover gaskets, resistance measurements will be incorrect.
4. Measure resistance between ground and each glow plug test point at glow plug injector adapter. If all readings are.1-2.0 ohms, go to next step. If any reading is not.1-2.0 ohms, probable cause is an open in Under Valve Cover (UVC) wiring harness or an open glow plug. Repair as necessary.
5. Measure resistance between Brown wire at glow plug relay and each glow plug test point at glow plug injector adapter. If all readings are.1-1.0 ohm, no problem is indicated at this time. If any reading is not.1-1.0 ohm, locate and repair open circuit.

Scheme 407

ENGINE PERFORMANCE DIAGNOSIS

Note. Repair each problem detected before going on to the next step. If repair corrects the original complaint, it will not be necessary to proceed to the next step or diagnostic procedure. However, if complaint is not corrected, continue with the testing until complaint is corrected.

Purpose of this test is to see if fuel system is getting sufficient clean fuel for engine to operate properly. Cloudy fuel indicates fuel may not be a suitable grade for cold temperatures. Excessive water or contaminants may indicate fuel system and tank may need to be flushed.

1. Connect a hose to fuel drain line at bottom of fuel filter. Place other end of hose into a suitable container. Open fuel drain. Start engine and observe fuel. Fuel flow should be a steady stream. Turn ignition off.
2. Turn ignition on. Check WATER IN FUEL warning light indicator. If warning light is on, fuel is contaminated with water. Service fuel system as necessary. If engine oil is present in fuel, injector "O" ring maybe defective. Perform «INJECTION CONTROL PRESSURE TEST»(ref-23714-S07747705732001010300000) . Repair oil leaks as necessary.

Note. Some sediment and water may be present in fuel sample if fuel filter has not been serviced for a prolonged period of time. A second sample may be necessary to determine fuel quality.

Checking engine oil helps determine if there is enough engine oil to operate fuel injectors. If there is little or no oil in crankcase, injectors will not operate.

1. Ensure vehicle is on level ground. Check engine oil. If oil is overfilled, engine may have been incorrectly serviced, or fuel is diluting oil and filling crankcase. Repair as necessary.
2. Inspect oil color. A milky White color indicates possible coolant contamination. Determine cause and repair as necessary. If oil level is low, top off oil. Ensure oil is correct type and viscosity.
3. Remove plug in top of oil reservoir and check oil level. If oil level is within 1" (25.4 mm) of oil fill hole, level is okay. If oil level is not within 1" (25.4 mm) of oil fill hole, check and repair cause of low fluid. Top off fluid.

This is a visual inspection to determine if an air intake restriction is contributing to a low power condition. If engine has a high intake restriction, a large amount of Black or Blue smoke may exist.

Note. If HIGH FUEL RESTRICTION indicator light is on, a restricted fuel filter may be causing low fuel pressure.

1. Connect Engine Pressure Tester (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. (Scheme 408)
2. Start engine and allow it to idle. Observe fuel pressure gauge and briefly raise engine speed to 3500 RPM. For fuel pressure specifications, see «FUEL PRESSURE SPECIFICATIONS»(/ford/pickup-f350/1996-1997/remont/specifications/#fuel-system-pressure-specifications) article. If fuel pressure is within specification, fuel pressure is okay. If fuel pressure is less than specification, replace fuel filter and retest. Cycle ignition switch several times to purge air from system. If fuel pressure is still low, go to next step.
3. Disconnect short fuel hose at fuel inlet line. Hose is located on left side of engine, close to frame rail. The larger of the 2 lines is the fuel inlet. The smaller line is the fuel return. Connect Fuel Pressure Adapter (014-00931-2) between fuel inlet line and vacuum gauge (0-30 in. Hg) of engine pressure tester.
4. 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. Check fuel regulator valve for sticking or debris. If vacuum is more than 6 in. Hg, check for blockage between pump and fuel tank. Repair as necessary.

Scheme 408

Purpose of this test is to determine if engine oil is aerated and causing poor idle.

CRANKCASE PRESSURE TEST

1. Ensure engine is at normal operating temperature. Remove turbocharger inlet pipe ducting. Remove inlet pipe and elbow that connects to air filter housing. Using cap provided in Engine Pressure Tester (014-00761), block air filter housing outlet. Install a protective screen over turbocharger inlet.
2. Screw Crankcase Orifice Restrictor (5631) and Crankcase Pressure Test Adapter (014-00743) into oil fill cap hole. Connect adapter to pressure gauge (No. 4) at engine pressure tester (014-00761). Ensure gauge has been zeroed.
3. Observe gauge and briefly raise engine speed to 3500 RPM. DO NOT block hole at top of crankcase orifice restrictor. Pressure should be less than 6 in. H(2)O. If pressure is 6 in. H(2)O or more, check engine mechanical condition (compression rings, cylinder bores, valves, etc.). Repair as necessary.

This is a visual inspection to determine if an exhaust restriction is contributing to a performance problem.

1. Visually inspect exhaust system for damage. Repair as necessary. Start engine. Briefly raise engine speed to 3500 RPM and inspect turbocharger exhaust backpressure butterfly bellcrank. Ensure bellcrank is not closed. When bellcrank tang is against stop, valve is fully open. (Scheme 404)
2. Connect New Generation Star (NGS) tester to Data Link Connector (DLC). Turn A/C off. Using scan tester, access EBP PID from PID/DATA monitor menu. See ADDITIONAL SYSTEM FUNCTIONS in the «TESTS W/CODES - 7.3L DIESEL»(ref-23600) article.
3. Observe PID reading and briefly raise engine speed to 3500 RPM. If PID reading is 28 psi (193 kPa) or less, exhaust system is okay. If PID reading is more than 28 psi (193 kPa), possible causes are: Collapsed or plugged tail pipe. Plugged or damaged muffler.

Perform this test to determine is engine can develop sufficient boost to obtain specific power. Possible causes for low boost are

1. Restricted intake or exhaust.
2. Low fuel pressure.
3. Low injection control pressure.
4. Faulty fuel injectors.
5. Faulty turbocharger.
6. Mechanical engine failure.

VISUAL INSPECTION

Perform visual inspection for

1. Damaged intake hoses.
2. Loose hose clamps.
3. Loose exhaust clamps.
4. Damaged turbocharger.
5. Restricted intake or exhaust.

If a problem is found, repair as necessary. If concern still exists, go to SYMPTOM DIAGNOSIS .

Turbocharger Leak Test

Check for loose connections or damage to air intake hoses and tubes.

Air leaks at the compressor manifold, intake manifold hoses or intake manifold covers can cause excessive smoke, loss of engine power or a noise condition.

Exhaust leaks at the exhaust manifolds or in the turbine housing will also cause loss of engine power and a noise condition.

Inspect turbocharger and components for loose connections or damage. Using a liquid soap on hose or tube connections will aid in leak detection.

Exhaust leaks can usually be detected audibly or visually by a discoloration caused by escaping hot exhaust gases.

Turbocharger Internal Oil Leak Test

Check the turbocharger compressor inlet for evidence of oil. If excessive oil is present, this indicates that the failure is in the engine, not in the turbocharger; for additional information, see appropriate SELF-DIAGNOSTICS article.

Check the turbocharger turbine outlet for evidence of oil. If oil is present in the outlet, remove the turbocharger from the engine and examine the oil supply and return passages in the turbocharger pedestal and engine block for restriction. If no restriction is found, replace the turbocharger.

See also:
• FUEL PRESSURE SPECIFICATIONS