dieselmann's Tech Page

Diagnosis by Symptom

Open the Glossary for acronym explanations.
Hard start/long crank--cold only
No/hard start hot or after stall, restarts after cooling; Jerky, irratic idle; DTC's P1211, P1212, P1283
No start at times; Intermittent stall when driving; Power "hitch" at cruise or under load; DTC's P0340, P0341, P0344
Hard start, irratic idle and/or loss of power, DTC P1298--All models; In wet weather--95-96 E-van
No throttle response, engine only idles, DTC P0220 or P0221; Vehicle bucks and jerks in parking lots, especially w/ manual transmission
Lack of acceleration when cold, limited RPM, hissing noise under hood, DTC P0470-478
Rough idle, especially when hot
Loss of power after hard accel; rough idle, "Check Engine" light on, DTC P1211
Rough idle--manual transmission; "Bearings in a can" rattle noise
96/97 stalling after a long decel/down grade
Stall when engaging reverse or manual first gear--auto trans
Surge/bucking and jerking at cruise
99 F-series lack of power, rough idle, "Check Engine" light on, sucking sound on acceleration
Hard start when cold, "Check Engine" light comes after starting, 97 and up California emissions
Intermittent light knock at idle or low speeds--98.5/99; 99.5/00
99 F-series loss of power or stall in 0° temps
97-99 E-vans with modified electrical systems--Hard start/Long crank
99 E-van Hard start/long crank
99 F-Series without cruise control, idles too low cold
99.5/2000 High Injection Control Pressure Readings
Damaged Valve Train Contact Request
98/99 E-Van; 99 F-Series built through 4-12-99, Check engine light/DTC P1298
Intermittent Computer Reset, 95-01 F- and E-Series
Oil leakage from cylinder head passage end plugs, 94-99
2000 Intermittent Missfire
Intercooler Hose Blows Off
Loose/Missing Turbo Bolts

Hard start/long crank--cold only:
This usually indicates a problem with the glow plug system.
Disconnect the Engine Oil Temp (EOT) sensor at the rear of the oil reservoir. This will cause the PCM to energize the glow plug relay for 2 minutes, and set a code. Turn the key to the run position and check for any voltage drop at the outlet side of the glow plug relay. The voltage should be greater than 10 volts during the glow plug cycle.
There is a history of burned and melted relay terminals and a couple of updated relays. Most recent part number is F7TZ-12B533-CA and can be identified by a gold-colored base.
If there is no voltage out of the relay, check for voltage in at the main terminal as well as key power and PCM-controlled ground at the two-wire connector. On 97 and newer vehicles inspect the bank circuit divider shunt for damage. If the relay tests fine test the glow plug resistance to ground at the valve cover connectors. The glow plug terminals are the outer two on 94-97, outer four on 98.5/99. Resistance should be 0.1-6 ohms depending on engine temp. A high reading could be the result of a spread or damaged Under Valve Cover harness or damaged valve cover gasket; re-check any high readings at the glow plug itself. Damaged UVC harnesses can be repaired with kits F7TZ-14489-AA for 97 and -BA for 94-96 trucks or replaced with F4TZ-9D930-K for 94-97 trucks or F81Z-9D930-AB on 98.5/99. Resitance from the glow plug relay to the valve cover connertors is 0-1 ohm. If no other faults are found, allow the vehicle to sit overnight. Before starting the engine, set the scan tool to monitor data stream and pick the EOT and Intake Air Temp sensors. The EOT and IAT should be within five degrees of each other. Next, remove the level-check plug from the HP oil pump reservoir and check the oil temperature with a thermometer to verify the EOT reading. If the EOT reading is higher than ambient (IAT) temperature, the PCM may be activating the glow plugs for too short a time, or not at all. If the problem only occurs at high altitude, and there is no glow plug system failures, the BARO sensor is most likley at fault.
Some 97 trucks have experienced a check engine light on after starting with Glow Plug Monitor circuit codes P1391, P1393, P1395 and P1396. After checking the glow plugs and the harnesses as in the above procedure, install a breakout box and check the GPM circuit to the PCM--GPML, LH bank terminal to pin 34; GPMR, RH bank terminal to pin 9; GPMH, relay output terminal to pin 8.
If there are no opens or shorts, re-flash the PCM to a higher calibration level. Also watch for an intermittent no output from the glow plug relay caused by oxidized internal contacts.

No/hard start hot or after stalling, usually re-starts after cool-down; Jerky, irratic idle; Possible DTC#'s P1211, P1212, P1283:
Usually caused by low injection oil pressure or regulator (IPR) valve. High pressure oil is used to pressurize and inject the fuel into the cylinders--each injector is essentially its own injection pump. The IPR is a by-pass valve that controls the high oil pressure depending on demand. The ICP monitors the oil pressure in the LH head.
Check for oil in the upper reservoir; it should be within one inch of the top; add oil as necessary. Verify that the correct oil is being used (see my PowerStroke Page for oil specs) and that it is not thinned out.
For no-start concerns check Injection Control Pressure (ICP) sensor readings with a scan tool or pressure gauge (500 min), or with DVOM at pins 87 to 91 (.83volt min) while cranking.
By using adapter fittings and plugs you can isolate and measure each cylinder bank to see if there is a high pressure oil leak in one head, or connect both HP oil pump hoses to the pressure gauge to measure pump pressure. NOTE: The 98.5 and later HP oil lines have special couplers requiring special tool 303-625 to disconnect, and tools 303-627 and 303-628 to connect to the coupler along with a pair of F4TZ-9N332-A elbow fittings to adapt to the HP oil gauge hose.
If isolated pump pressure is low, short break-out-box pin 83 to ground to run IPR valve to full duty-cycle. If the pressure comes up (3600 psi) replace the PCM; if it remains low, remove and inspect the IPR o-rings for damage; a kit is available if they are. If the IPR o-rings are undamaged, replace the IPR valve. If there is still low oil pressure, replace the HP oil pump.
If isolated HP oil pump pressure is 500 psi, or only one bank reads low, remove all the fuel injectors and replace their o-rings using the latest kits P/N F8TZ-9229-AA.
If the concern is a jerky, irratic idle when hot, unplug the ICP sensor (will set a code, causes the PCM to default to a pre-selected IPR duty cycle) to see if it the idle stabilizes. If it does, check the ICP voltage with a scan tool or breakout box at pins 87 to 91 with the sensor plugged in and the key on/engine off. It should be .20-.25 volts. If the base ICP voltage is within specs, replace the IPR; If not, replace the ICP and retest.

No start at times; Intermittent stalling while driving during warm-up or when hot, usually restarts; Power "hitch" at cruise or under load; Possible DTC#'s P0340, P0341, P0344:
Cam Position (CMP) sensor.
The CMP sensor provides the PCM with cylinder ID and engine RPM. Sometimes hard to detect, even with a scan tool while monitoring the RPM signal. If the PCM does not receive a clear CMP signal, it won't signal the Injector Driver Module (IDM) to energize the injector solenoids.
If this symptom occurs, or if you find one or more of the above codes, check the wiring to the CMP for continuity--BOB pin 90 to CMP pin B; BOB pin 65 to CMP pin A; BOB pin 49 to CMP pin C. NOTE: A code P0344 may be set any time the engine is cranked for an excessive period of time. Early CMP sensors were @ 1.152" in length, and with the different materials--plastic sensor, aluminum timing cover, steel tone ring) the air gap would change drastically during engine warm-up. There were TSB's published for shimming the sensors 0.010" to cure these problems as well as the drastic repair of replacing the camshaft--something a Navistar tech assist rep recommended not doing even if excessive end play was verified. There have been two updates to the CMP. One to decrease the length to 1.142", and also to improve the internal circuitry for less "noise". The CMP designed for engines built after serial number 375549 have gold-plated terminals and cannot be substituted with those designed for previous engines.
94-96 CMP: F6TZ-12K073-A; original Navistar part suffix C-96, C-97; replaced by C-98; replaced by C-99
97 CMP: F7TZ-12K073-A; early suffix C-91; replaced by late suffex C-92; both replaced by C-93.
The suffex is stamped on the connector end of the CMP and can be used to identify the level of the part installed. Replace any CMP's with a suffex of C-96, 97, 91 if these symptoms are experienced. Lube the o-ring and connector with silicone dielectric grease when installing.

Hard start; Stalling; Irractic idle and/or loss of power; DTC P1298 all models--95-96 Econoline in wet weather:
Injector Driver Module (IDM).
The IDM converts 12 volt battery power into 110 volts and activates the injectors as directed by the PCM. On some Econolines water may enter the IDM causing the above symptoms. To diagnose, remove the LH battery and the coolant overflow bottle and access the IDM which is mounted behind the coolant bottle. Remove the IDM(both ground strap bolts need to be removed) and shake it, listening for a sloshing sound. Water running off the roof and cowl areas can enter the IDM; there is a service replacement IDM--F6TZ-12B599-AA--that has improved sealing. Also install foam seals (1)F6UZ-13C795-AA and (2)-BA on the back of the IDM.
If the DTC P1298 is alone when performing code retrieval, replace the IDM; if other codes are present, diagnose them first.
A faulty IDM can cause driveablity concerns similar to a malfunctioning ignition module in a gas-powered vehicle. Under load it will seem as if the engine is starving for fuel. If you verify good fuel and oil delivery and pressure to the heads, and the Mass Fuel Desired, ICP, IPR and Fuel PW readings climb while the RPM's drop, suspect the IDM.

No throttle response, engine idles only, DTC's P0220 or P0221; Vehicle jerks in parking lots, especially manual transmission:
Idle Validation Switch.
The IVS tells the PCM that the accelerator pedal has returned to the idle position. Even if the pedal is fully depressed, if the IVS remains off, the engine will only idle. Watching the IVS and AP data stream, the IVS should switch on below 1.41 volts according to Ford. Navistar spec is 0.2-0.3 volts above base AP voltage. If the PCM sees the Accelerator Pedal sensor voltage increase with out the IVS switching on, it may set a code. The IVS and AP sensor cannot be replaced without replacing the entire pedal assembly. If the IVS switches on at too high of a AP voltage, it can cause the truck to buck at low speeds as the IVS cycles on and off as the driver tries to control his speed. The only way to correct this is to first loosen and turn the AP sensor to reach the lowest possible voltage reading on the scan tool and retighten. Then bend the IVS stop to adjust the on/off point to 0.2-0.3 volts above the base AP voltage reading. Note: There have been cases of lack of throttle response and the above codes which were caused by the PCM not recognizing the IVS "on" signal. Replacing the PCM corrected the problem.

Lack of acceleration when cold; Limited RPM; Hissing noise under hood; Possible DTC's P0470-P0478:
Exhaust (back)Pressure Regulator valve/servo.
When the engine is cold--EOT less than 140 degrees--and the ambient temperature is less than 37 degrees, the PCM activates the EPR solenoid to divert oil pressure to the EPR sevro which closes the EPR valve at the turbo outlet. This causes exhaust backpressure to help the engine warm up more quickly. The PCM monitors the amount of backpressure through the Exhaust BackPressure sensor. On accel, the EPR is deactivated, but if the valve sticks, it will cause the above symptoms. You may or may not be able to duplicate the concern, since it normally only occurs on initial start-ups when the PCM activates the EPR for prove-out. If you are able to duplicate it, inspecting the position of the EPR linkage can confirm the problem (the servo linkage will be extended and the bellcrank tang will not be on its stop). To repair, replace the turbocharger pedistal.
A similar condition can occur if the EBP sensor tube plugs up with carbon, causing the PCM not to see an increase in exhaust back pressure resulting in the PCM not deactivating the EPR solenoid. Remove the tube and inspect for blockage. Clean as necessary.

Rough idle, especially hot:
Could be caused by anti-foaming agent depletion, incorrect oil, or leak at the oil pump pickup tube.
Get the engine and oil hot and run up to 3300 RPM for three minutes. If the ICP reading goes above 1600 within the first thirty seconds of testing there could be a cracked pickup tube or missing seal. The pick-up tube can be checked by adding two quarts of oil to the crankcase and raising the rear of the vehicle approximately ten inches. If the ICP readings at 3300 RPM drop, then the pick-up tube is cracked or leaking.
If at the end of the three minute high RPM test the ICP readings are above 1400 for Federal or 1250 for California and Econoline or 1500 on 99.5, the anti-foaming agents are depleted from the oil or the wrong oil is being used.

Loss of power, usually after a hard acceleration; Rough idle; Check engine light comes on, DTC P1211:
Intermittent high pressure oil leakage.
This condition usually occurs when the vehicle is cold and the oil is thick. When performing a hard acceleration, the truck suddenly looses power, the check engine light comes on, and once returning to idle the engine runs rough and won't accelerate. Cycling the key may correct the concern, clearing the code from the PCM will correct it temporarily. If you can monitor data stream, at idle the ICP pressure normally is 400-700 PSI and the IPR duty cycle is 9-14%; at cruise, ICP is 700-1200 pSI and IPR is 15-20%; under normal acceleration, ICP is 1200-2000 PSI and IPR is 20-30%; and under WOT accel, the ICP is up to 3600 PSI and the IPR is 35% or higher. When the above symptom occurs, typically the idle ICP reading will be normal, but the IPR duty cycle will be high--over 20% and up to the max 50%. A "blow-by" condition has occured somewhere in the HP oil circuit. If you can get the problem to re-occur with some frequency, the most probable cause is worn or deteriorated injector or IPR o-rings. If the problem is intermittent, it could be a sticking IPR valve. Replace the injector o-rings with the latest-level kits--F8TZ-9229-AA. When replacing the IPR, make sure you get the correct part for the build date/serial number of your engine.

Rough idle, manual transmission trucks; "Bearings-in-a-can" rattle noise:
Dual mass flywheel.
Ford uses a two-pieces flywheel to dampen out the engine vibrations to prevent damage to the ZF 5-speed trans--99 trucks equiped with the new 6-speed trans have a standard flywheel. Occasionally either the bearing that supports the rear half of the flywheel fails, or the dampening springs loose their tension. The result is a rougher idle, sometimes described as a miss at idle, often accompanied by a rattling noise. Increasing the RPM usually negates these symptoms. Running the KOER and Cylinder Contribution tests makes the noise worse. Replacing the dual mass flywheel is the only fix for this situation. Use P/N F7TZ-6477-DA.

1996-97 PowerStroke Stalling intermittently after a long deceleration in manual first or second gear in automatic trucks, or in low gears with ZF 5-speed, when shifting back up into a higher gear or depressing the clutch may be corrected by: performing electronic engine control diagnostics; replacing the oil with the recommened SAE weight for the ambient temp (see my PowerStroke Page) and API rating; replacing the Injection Control Pressure sensor (ICP, P/N F6TZ-9F838-A) with one that has a date code of 6318 or higher ("C916318A" 6=1996, 318= Julian date Nov. 15); and adding a pint of Lubrizol 888 or Fleetrite CH1824392.
Note: California vehicles with E4OD automatics need to have the calibration of their powertrain computer updated as per TSB # 98-4-14.
Similar condition:
If you have a customer that drives in low gear at idle speed for an extended time then experiences a stall when depressing the clutch, instruct the customer to drive in low range when this condition normally would occur. The stall is most probably caused by the PCM seeing the accelerator pedal in the idle position (IVS "OFF") and a load on the engine and adapts to this mode. Depressing the clutch suddenly removes the load, the PCM over-compensates, and the engine stalls. There is no repair for this condition

Stall when engaging transmission (automatic, usually manual low or reverse):
Torque Converter Clutch.
This may be caused by the TCC being engaged at idle. On trucks built before 9-20-95 the correction is a new transmission front pump and/or torque converter. On trucks built after the above date, it could be cause by a loose transmission filter. In this case, install a flat magnetic strip (from a Tempo ATX or Ranger A4LD transmission) in the trans pan below the filter pick up to retain the filter in place or use an updated filter from Ford that has bumps cast into the plastic to help it stay in place.

Surge/buck/jerk at cruise, 50-60 MPH/1500-2000 RPM, 96 trucks after "California Cackle" calibration update, 97 and 99-2000:
There is a revised computer program for 97 California and 99-2000 engines to correct this concern. This is intended to correct the problem if it occurs when the cruise control is on. Broadcast Messages 9817 & 0054; TSB # 00-25-4.
If this condition exsists in a 96 model/year truck, if the condition is not completely resolved after this fix, or if it occurs only with the cruise off, try using synthetic engine oil. Since most of the synthetic oils on the market are not specifically designed for use in the PowerStroke, a pint of the anti-foaming agent must be included in the oil change--Fleetrite/Navistar CH1824392 or Lubrizol 888. This may dampen the symptoms to an acceptable level.

Revised Air Cleaner and Filter, 99-2001 F-series/Excursions built before 11-25-00:
This new air cleaner assembly is to correct lack of power concerns caused by a collapsed air filter element. The element now has a 3" pleat, and the air cleaner cover has a post to keep the element in position. May be used to replace any air cleaner from model/year 99 up to 11-25-00, at which time it became production. TSB #01-9-5.
Air Cleaner Assembly: 1C3Z-9600-AA; includes element FA-1710
Trucks built prior to 12-7-98 still with the original air box can use the following older TSB that now includes the newer air filter:
99 F-series loss of power; snow injested into air cleaner--trucks built before 12-98. Ford has a new air cleaner box which went into production on 99.5 trucks. This new air cleaner moves the air intake from the fender well to the radiator support and incorporates a LH battery cover. The modification requires removing the LH battery tray and blanket, replacing the P/S return hose from the Hydra-boost and triming the LH radiator air deflector. TSB# 99-6-4
Air cleaner kit: XC3Z-9K635-AA
This may be a more preferable fix to the shortening of the air intake tube as described in TSB#98-16-11 as this condition affects original and shortened air cleaner boxes:
Lack of power; rough running; Check engine light on; Sucking sound on acceleration--99 F-series:
This could be caused by dirt and water being drawn into the air cleaner. There is a revised air cleaner box that can be installed to correct this--P/N F81Z-9600-BA. If the revised air cleaner box is unavailable, the condition can be resolved by modifying the air cleaner snout: Mark the snout where it enters the fender; remove the air cleaner and cut off the end of the snout 5mm/0.2" from the fender side of the mark; reinstall the air cleaner. The end of the snout should stick into the fender slightly. TSB#98-16-11
I have seen this problem show up in very fine dust conditions without rain.