Diesel Vehicle Service

Our Drive-in facility is your resource for quality repair & technical information concerning performance and maintenance of your diesel vehicle. It takes a special kind of person to own & operate a diesel and it takes a special kind of company to repair and service one. Whether you need a simple fuel filter change, an electronic fuel system diagnostic, or an exhaust brake, we are your experts! If you use your diesel for work or play, our goal is to assist you in obtaining optimum performance and if a repair is necessary, to complete that repair as soon as possible.

Does your diesel belch black or white smoke? Have you lost the raw power you bought your diesel for? Is it difficult to start your engine? Call us and we will make the smoke disappear, retrieve the lost power, and make starting a simple turn of the key. Even many of the most experienced gasoline mechanics won't touch a diesel engine. Let our fully trained diesel technicians diagnose the problem your vehicle may be having and remove & replace your fuel injection pump, injectors, or turbocharger (gas & diesel) when a repair is needed.

Having starting problems? Our technicians are experienced in diagnosis and repair of starting systems and glow plug systems.

Oregon Fuel Injection has been doing diesel vehicle service and fuel system diagnostics since 1982. We own several diesel vehicles (Ford PowerStroke, Dodge 24 valve, Chevrolet Duramax, Chevrolet Tahoe 6.5L, Chevrolet 6.2L pick-up & blazer), and have owned others in the past, such as Volkswagen Rabbit and GMC Jimmy 6.2L.

The following problems/solutions listed are what we commonly find in our service facilities. While we don’t advocate replacing parts before complete diagnostics are done, many of you may not have access to a scan tool or a repair shop completely familiar with your vehicle. Proper diagnostics involve having the correct service manuals and equipment to do the job right. Part replacement without complete diagnostics is like shooting in the dark. You may or may not solve the problem. Use the following “common problems” information keeping the above in mind.

We recommend installation of the pryometer probe (stinger) into the exhaust manifold ahead of the turbocharger. The reason for doing it, "this way", is to get a more accurate temperature reading. The "Old Rule of Thumb" that the reading was 150 degrees less if installed after the turbo is no longer accurate. The difference in temperature readings varies with boost pressure increases, for example, at 15 PSI boost pressure the difference will be about 150 degrees. Many of todays engines run 30 PSI (300 degrees difference) to 40 PSI (400 degrees difference) of boost pressure ,particullary afer performance modifications. In other words if the probe on your pick up is installed after the turbo and you are getting 900 degrees at 30 PSI boost, the true temperature of the exhaust gases are (900+300) 1200 degrees.

There has been concern that the probe may break off and go through the turbo, we haven't seen a broken Isspro pyrometer probe in over 15 years.

Low Power -
Always change the fuel filter before doing further diagnostics if it is dirty, or if it has been more than 7,500 miles since the last change.

Fuel Filter Change -

1. We recommend changing the fuel filter(s) every 7,500 - 10,000 miles.
Note: Dodge is the only manufacturer that recommends a different interval for severe service. That makes sense, because during severe service use you normally burn more fuel, thus the filter has to filter more fuel.

2. DO NOT fill the fuel filter through the fuel outlet! A secondary fuel filter is normally rated at 8-10 microns, 25 microns = .001 of inch. You can’t see the contamination that a filter will remove from the fuel. If there is a way to prime the fuel system without filling the filter (electric fuel supply pump or hand primer) do that. If not, then fill the filter through the inlet holes (usually the smaller outside holes), that way the fuel will be filtered before it gets to the injection system. The newer fuel systems need even closer tolerances, HEUI (like Ford PowerStroke) 4-7 microns, high-pressure common rail (like Duramax and 2003 Dodge) require 2-4 micron filtration. We carry the O.E. filters for Dodge, Ford, and Chevrolet diesels as well as add on units from Racor.

3. If you want to know how dirty the fuel filter was - don’t cut it open. Vigorously shake it out into a clean container. Look for extreme amounts of contamination (fuel is like mud) or water. That will help determine fuel filter change intervals.

94-03 7.3L POWERSTROKE:

94 - 03 7.3L Diagnostics on PDF

This guide is not a substitute for the proper diagnostic manuals and a scan tool. It is intended to be used with the proper tools to help diagnose and solve drivability issues.

PEFORMANCE BOXES
 Performance boxes that tap into or connect into the vehicle wiring should be removed to make certain that they are not causing any of the following complaints. Also chips, including downloaded ones like superchips, can cause false MAP readings on the scan tool. They will cause the actual EBP and MAP to go higher due to more fuel delivery.

OIL LEVEL
 Low or dirty oil can cause intermittent low power, miss, rough run, no start etc. Make sure the oil level is correct and the oil is in good condition (less than 3000 miles before trying to cure any other drivability or starting issues.

DIAGNOSTIC CODES
 Most PowerStroke that we see, with starting or performance issues don't set codes, if you have DTC codes, proceed to the DTC code section first. If you don't have a scan tool, the diagnostics, other than visual examination or parts changing, is difficult at best.

NO START
 1. DTC P0340 Bad CMP Sensor
 2. Are you getting smoke while cranking (after about 10 seconds) if no smoke then no fuel is getting into the engine
 3. Low oil level
 4. Fuel supply pressure low; Plugged fuel filter or no fuel in tank, minimum 20 psi cranking, and 99-03 should be 50 psi cranking
 5. Refer to Hard Start or No Start Issues below

NO START OR HARD START COLD
 1. Check to make sure that 10.8 or more volts are going the glow plugs from the relay. The glow plugs don't cycle until EOT (engine oil temp.) is below specification, which varies by vehicle year. The engine should start without the glow plugs energized down to about 40 degrees. Look at the volt gauge in the dash, the glow plugs will cycle up to 120 seconds depending on EOT
 2. Refer to No Start or Hard Start Issues below
 3. Bad wire harness connections at the valve cover gaskets, internal or external connections. Examine the connections, do pin tension tests also smell for burnt wires.
 4. Injectors bad; Injectors with high miles on them can fail to operate cold. If correct PW displays on cranking you can remove the valve cover and watch the oil spill discharge, every injector should discharge oil when pulsed by the IDM during cranking. If no pulse of oil then the injector isn't activating and putting fuel into the cylinders. Running several buzz tests cold will sometimes free up the injectors. This is a typical high miles with inadequate engine oil changes problem.

NO START OR HARD START HOT
 1. Refer to other hard start or no start issues below
 2. IPR (Injection Pressure Regulator) bad, will cause low ICP
 3. IPR o-rings bad, will cause low ICP
 4. Injector o-rings bad, will cause low ICP. Should also show up as black fuel (from oil in fuel) in fuel filter canister.
 5 High pressure oil pump bad, will show up as low ICP
 6. Engine oil worn out or too thin
 7. Cranking speed too slow, should be 180 rpm minimum when warm

OTHER NO START OR HARD START ISSUES
  When trying to diagnose hard start or no start issues a scan tool is needed to check and monitor the ICP (Injection Control Pressure), RPM (From the CMP) Vehicle Voltage during cranking and PW (Pulse Width) signal.
 1. RPM, minimum 100 rpm cranking speed (When warm it should be over 180 rpm)
 2. ICP, minimum required for starting 500 psi if no rpm signal, ICP won't go over 400 psi
 3. Voltage during cranking 7-10 volts minimum depending on year
 4. Pulse Width; 0 ms means no sync, 1994-1997 .42 ms indicates that PCM and IDM are in sync (on 99-03 it should be .60 ms) and the PCM is waiting on the ICP to reach the minimum pressure. When min. ICP is reached PW should change to 1-6 ms
 5. If any of the above doesn't meet the minimum specification, solve the problem as-per the appropriate Ford Diagnostic Manual.

LOW POWER POOR MILEAGE
 1. Fuel filter dirty; recommend changing every 8-10,000 miles
 2. Air Filter dirty; the filter minders don't always work, visually inspect the air filter for excessive contamination. CAUTION; When inspecting or changing the air filter on the 94-97 PowerStroke, make sure to clean out the air filter housing, because setting the filter back in on top of the bugs and dirt that dropped off will result in turbo or engine damage from unfiltered air.
 3. Exhaust leak before the turbo at the turbo feed pipes or the donuts that seal them.
 4. Fuel filter housing return screen, in the 1994-1997 the screen will become plugged not allowing aerated fuel to return to the tank.
 5. Throttle voltage should be 3.85-3.95 volts at WOT; check floor mats or a bad throttle assembly
 6. Fuel supply pressure below 50 psi can cause a low power or hesitation problem. Check at idle and at WOT a plugged fuel filter, bad fuel pressure regulator, bad supply pump or a restriction in the tank can cause low pressure.

LOW POWER POOR MILEAGE
 To make further checks you need to monitor the following PIDs with a scan tool. Normal readings for EBP (exhaust back pressure) MAP (manifold air pressure, boost) and BARO (barometric pressure) Note; all readings are in absolute pressure, so you must subtract KOEO (key on, engine off) MAP readings from WOT (Wide open throttle) readings to get gauge pressure. The following readings are for about 500-1000 foot elevation, higher elevation will give lower base readings due to lower atmospheric pressure.
IE: At 5000 foot elevation BARO would be about 12.1 psi

 NOTE; at KOEO all three readings should be within .2/10ths, if not repair or replace the bad sensor before continuing. BARO won't change with the engine running

1994-1997	KOEO	IDLE	WOT, HARD ACCERERATION
EBP	14.2	14.3-14.4	28.0-32.5 psi
MAP	14.2	14.0-14.1	27.5-30.0 psi
BARO	14.2

Boost pressure, net (gauge) is 13 psi minimum

1999-2003	KOEO	IDLE	WOT, HARD ACCERERATION
EBP	14.2	14.5-14.8	38.0-43.0 psi
MAP	14.2	14.0-14.1	30.0-32.0 psi
BARO	14.2

Boost pressure, net (gauge) is 16 psi minimum

EBP; Will typically gain .2 psi on 94-97 and .5 psi on 99-03
 Low readings at WOT mean that there isn't enough pressure (exhaust gas velocity) to spin the turbo up to full boost
 High readings at idle mean that the exhaust isn't flowing or the turbo isn't spinning, some sort of exhaust flow restriction. Early 99 may have 2 psi more EBP due to the cat. Converter

MAP
 Low readings with normal EBP usually mean a boost leak at the intercooler hoses or at the manifolds
 Low readings with low EBP usually mean another cause, did you check the list above

Next check ICP (injection control pressure) and IPR (injection pressure regulator), because low oil pressure can cause low power. Pressures are approximate. If the IPR duty cycle % is high, but the ICP is low, it usually means some sort of high pressure oil leak. WOT in neutral pressure reading is taken after 3 minutes of running at WOT no load (neutral)

1994-1997	IDLE	WOT in neutral	HARD ACCELLERATION
ICP	575-600	1300-1400	2450-2700 psi
IPR	11-14%	18-21%	35-40%

1996-1997 California emissions is like the 1999-2003 specification

1999-2003	IDLE	WOT in neutral	HARD ACCELERATION
ICP	475-490	1100-1200**	2450-2750 psi
IPR	9-11%	18-21%	35-40%

** After engine s/n 896812 maximum no load after 3 minutes would be 1800 psi
The ICP will default to 725 psi at idle if the PCM isn't getting the signal

ICP LOW; if the IPR duty cycle % is high, but the ICP is low, it usually means some sort of high pressure oil leak or bad IPR. This can also be caused by IPR o-rings, high pressure pump, or injector o-rings. Follow the Ford Service information to diagnose high pressure oil leaks or lack of pressure.

MISS OR ROUGH RUN
 1. Check valve cover connectors for burnt or bad connections, do a pin tension test.
 2, Manual Transmissions; check for bad dual mass flywheel, this will cause false cylinder contribution codes if the flywheel is bouncing around.
 3. Run a cylinder contribution test.
 4. Check the turbocharger compressor wheel, if dusted or damaged from poor air inlet filtration, run a compression test before replacing any injectors. Low compression will cause a rough run.

STALLING INTERMITTENT
 1. DTC P0344 CMP sensor erratic
 2. Loose IPR Solenoid or chaffed wires at solenoid
 3. Low engine oil

KNOCK OR CACKLE
 1. Low fuel supply pressure, Normal Pressure as follows;
      1994-1997; 50 psi at idle and 55 psi at WOT
      1999-2003; 50 psi at idle and 45 psi at WOT
 2. Aeration in the oil

CHIRP OR COMPRESSOR SURGE AT SHIFT POINTS
 When a 99 ½ to 2003 has been "hopped up" it can cause the compressor wheel to chirp or surge at higher boost levels (25 psi or so). You need to replace the compressor wheel with the same wheel used in the 1994-1997 turbos.

EXCESS ENGINE OIL CONSUMPTION
 1. Bad injector o-rings, on the 94-97 oil from the leaking o-rings will return back to the fuel filter housing and the fuel will be black from oil.
 2. Internal o-rings can cause excessive oil consumption and not show up as black fuel.
 3. 99-03 engines don't have a fuel return off the heads, so in the unlikely event of injector o-ring failures, the fuel will not be black from oil.
 4. Turbocharger; this engine is a closed crank vent system, which means it pulls crank vent fumes into the inlet of the turbocharger. You must compare the amount of oil at the compressor inlet with the amount of oil at the compressor outlet, before condemning a turbocharger. Excessive blow by will be pushed out the crank vent and pulled in by the turbocharger.

SURGE AT IDLE
 1. ICP circuit problem, disconnect the ICP sensor, if the surge goes away then you possibly have a bad ICP sensor.
 2. AA code injectors installed into a engine that require AB code injectors will cause a surge (California emissions engines in 96 and 97 require AB injectors)

DTC CODES

DTC P0340;
 1. Usually a bad CMP (cam position sensor)

DTC P0344;
 1. Usually a bad CMP
 2. Can be caused by excessive cranking

DTC P0476
 1. Can set if the vehicle is equipped with an exhaust brake.

DTC P0603 KAM (keep alive memory)
 1. If the batteries were previously disconnected, this code will set and be stored until cleared.
 2. If the PCM was unplugged this may cause this code to set.

DTC P0605
 1. If there is a chip plugged into the PCM that will cause this code.
 2. Excessive cranking can cause this code.

DTC P1211 Indicates that the injection control pressure was above or below command desired during self test mode.
 1. Check Oil level.
 2. Possible bad IPR or IPR o-rings

DTC P1212 will set if 725 psi ICP is not detected in 6-15 seconds of cranking.
 1. Check oil level.
 2. Possible bad IPR or IPR o-rings.

DTC P1261 to 1268 LOW side to battery +
 1. Check valve cover wire harness connections first, including under the valve cover.

DTC P1271-1278 Low to high side open
 1. Check wire harness connections and pin tension of valve cover connections

DTC P1280 ICP Circuit low, PCM will default to 725 psi at idle

DTC P1298
 1. If other codes are present repair those first.
 2. IDM likely bad, replace

Miscellaneous Information

Oil Change Intervals; Oil changes done at 5000 miles when the vehicle is driven in the severe service category (3000 mile change interval) will result in failures of turbochargers, IPR, High Pressure Oil Pumps, and Injectors before the "normal" life expectancy.

Diagnostic information available from the following:
 1. www.Motorcraft.com on-line sign up by the day, month or year, follow the links to technical resources.
 2. www.helminc.com Service manuals and Powertrain and Emissions Control Diagnostic manuals.
 3. www.Auto-Video.com 7.3L Diagnostics on DVD, you must have scan tool to make this DVD worthwhile.

83-94 6.9L & 7.3L IDI:

Surges -
1. Air in the system, most likely caused by a stock water separator. Check for air at the schrader valve on the side of the filter housing. If the air is coming from the separator, replace it with a Racor fuel filter water separator unit and mounting kit.

Hard Start/No Start Cold -
1. Glow Plugs bad - If all the glow plugs are burned out, then the controller and relay must be changed, because power was applied for too long. If not, the system may work fine for a while, then the relay or controller will “stick” on burning out the glow plugs again.

2.Glow Plug Controller - The solid state glow plug controller reads total resistance, if the ground connections are not clean or the glow plugs are “tired”, the system will short cycle (3-4 seconds instead 7-8 seconds). Use a Digital OHM meter to test, maximum resistance .4 Ohms (if the leads together on your meter read .1-. 2).

Starts Then Dies -
1. Runs 1-10 seconds on cold start after sitting overnight, if it starts good than the glow plug system should be good. This is normally caused by fuel draining back.
Typical causes - Any fuel leaks, throttle shaft, injector return tees, or at the supply pump.
2. 7.3L - The fuel filter check valve can also cause a fuel drainback. The longer the engine stays running after starting, the further from the injection pump the problem is.

Dies on Deceleration -
1. This most commonly happens with a manual transmission when the clutch is pushed in as you are coming to a stop. Water can cause this so check/change the fuel filter. Low lubricity fuel can also cause the metering valve to “hang”. Add some Stanadyne Performance Formula. Make sure the idle speed is set at 650-700 rpm. If these items do not solve the problem, you may need to change the injection pump.

1998-2002 DODGE 24 VALVE DIAGNOSTICS

1998 - 2002 Dodge 24 valve Diagnostics on PDF

CHECKING FUEL SUPPLY PUMP PRESSURE:
The fuel supply pump pressure is critical for the longevity of the VP44 injection pump. The fuel supply pump should maintain at least 4psi at the inlet to the injection pump on a W.O.T. test drive. Failure to maintain a pressurized flow of un-aerated fuel will cause injection pump damage.

4psi at the inlet to the injection pump with a clean fuel filter allows for a pressure drop across the fuel filter when it is dirty. According to Chrysler, pressure doesn't matter, only volume. The problem with their volume test with an unrestricted flow is their specifications for volume aren't high enough. Some vehicles with the updated in-tank supply pump won't maintain a positive pressure during a test drive. When the supply pump in the injection pump is pulling more fuel than the supply pump in the tank is pushing, then pressure becomes a vacuum because volume isn't high enough. Continued driving, when fuel is under a vacuum, can cause cavitations, which will damage the injection pump.

In order to maintain good fuel flow, especially with performance modifications, you may need to add an additional supply pump.

NOTE: The following information is not a substitute for the proper diagnostic manuals, but to share some of the common problems we have run across.

PERFORMANCE BOXES:
Performance boxes that tap into, or connect into, vehicle wiring should be removed to make certain that they are not causing any of the following complaints.

INJECTORS:
"Normal" life seems to be about 150,000 miles. When injectors are going bad, they can cause many different intermittent problems, such as: no start, hard start, black smoke, low power, white smoke and rough running.

LOW POWER:
1. Low or no fuel supply pressure.
2. Dirty air filter or inlet restriction.
3. Exhaust leak before the turbo.
4. MAP sensor can go bad and not set a code, check reading with scan tool versus actual.
5. Injectors bad

NO START:
1. Low or no supply pressure.
2. No fuel - sending unit in tank defective.
3. If the supply pump recently failed, it could damage the injection pump and cause a no start.
4. Check for DTC, follow Powertrain Diagnostic Procedures Manual.

INJECTORS BAD:
1. Check injectors, remove injection lines and crank engine. Do any of the injector feed tubes pump compression back out while cranking? Replace injector, if needed.
2. CMP sensor defective.
3. Injection pump

HARD START: HOT OR COLD
1. Follow the same guidelines as no start.
2. Fuel leaks at injector feed tubes, internal or external?
3. If supply pump recently failed, it could cause injection pump problems due to cavitation damage.

MISS:
1. Check for DTC.
2. Check injectors.
3. Leaking fuel injector tubes may also cause a miss. If they leak externally, they are also leaking at the injector connection.

SURGE WHILE DRIVING:
1. No or low fuel supply pump pressure.
2. 98 & early 99 automatic transmission, see TSB on erratic torque converter clutch operation - needs reflash

SURGE AT IDLE: OR RUNS ERRATIC AT IDLE
1. No or low fuel supply pressure.
2. DTC present? Look at solving the codes first.
3. With black smoke and no DTC, possible bad injectors.

In addition to the information in the Diagnostic Procedure Manuals, consider the following checks and information.

DTC 215 - Fuel Injection Pump Control Circuit
1. Swap injection pump relay with horn relay and retest.

DTC 216 - Fuel Injection Pump Timing Failure
1. If supply pump previously failed (within the last 2-3 months) it could cause advance component and housing damage in the injection pump.
2. Low or no fuel supply pump pressure.
3. Improper installation of replacement injection pump. Key not aligned with gear and gear pulled onto shaft with driveshaft nut.
4. Injection pump drive gear installed one tooth off.

DTC230 - Transfer Pump Circuit Out of Range
1. Bad fuel Supply pump will normally cause this code.
2. Could also cause a DTC216.
3. Could set due to excessive cranking, see hard start diagnostics.

DTC336 - Engine Crankshaft Position Sensor (CKP) Signal
1. Indicates no engine speed or position signal to ECM.
2. Can cause other codes, solve DTC336 first.
3. Reads out on scan tool as ECM engine speed.
4. Will cause multiple problems, such as surge, miss erratic run, hard start, no start, stalls, etc.

DTC370 - Fuel Injection Pump Speed / Position Sensor Signal Lost
1. If no other DTC, pump is likely faulty.

DTC602 - ECM Fueling Calibration
1. Could be caused by a performance box.
2. Can also be caused by a DTC336.

DTC1688 - Internal Fuel Injection Pump Failure
1. This code can be caused by a bad crank sensor (DTC336)
2. If no other DTC, most likely injection pump needs to be replaced due to an electronic failure.

DTC1689 - No Communication Between ECM and Injection Pump Module
1. Can be caused due to excessive cranking - See hard start & no start diagnostics.
2. Wires chaffed at pump connection.
3. Performance box problem.
4. Fuel pump relay bad (swap with horn relay and retest).
5. Possible defective pump.

DTC1690 - Fuel Injection Pump CKP Sensor Does Not Agree With ECM CKP
1. Monitor RPM reading of the following: ECM engine speed (crank position sensor See DTC336) vs. engine speed CMP (cam position sensor) vs. injection pump engine RPM (from injection pump).
2. Can be caused by a DTC336 - repair DTC336 FIRST

DTC1691 - Fuel Injection Pump Controller Calibration Error (PSG)
Likely an injection pump problem.

DTC1693 - DTC Detected in PCM
The JTEC controller is reporting that there is a DTC stored in the PCM.

DODGE SPECIAL TOOLS millerspecialtools.spx.com Miller (Dodge) special tools

94-98 DODGE 12 Valve:

Intermittent Slow/Hard start or Low Power -
1. Check that the shutoff solenoid is working and getting full travel. They commonly break or fail to completely pull in without help.

Low Power, Miss, Blue/White Smoke -
1. Low fuel galley pressure can cause this, particularly when the engine is cold. Fuel galley pressure (check at inlet to injection pump) should be 20psi at idle and a minimum of 25psi at 2500rpm. If it is low, the most common problem is the overflow valve, but a weak fuel supply pump can also cause the same problem, as well as restricted fuel supply.

89-93 DODGE:

Slow to shut off -
1. Remove the overflow valve and tap out onto a sheet of white paper, or remove the shutoff solenoid. If there are a lot of metal particles, the injection pump is coming apart inside (we see this happen frequently after approximately 150,000 miles) and must be changed along with the injectors (the metal will have been pumped through the injectors).

Miss around 1200 rpm -
1. As above, if the pump has a lot of metal in it, the metal can plug some of the spray holes in the nozzle tip. If there are holes plugged in the nozzles, find and fix the cause before replacing them (if the problem is in the pump, the replacement nozzles will soon plug as well).

82-00:

Hard Start Hot (after sitting 10 minutes to 2 hours) -
1. 6.2L and 6.5L engines need a minimum of 200rpm hot cranking speed (the fan should be a blur). If cranking speed is too slow, they are hard to start (between 120° - 180° coolant temperature) hot, but start fine cold. Check battery connections, batteries, cables and starters. Fix a slow cranking problem first, then if it still starts hard, it could be a problem with the injection pump.

94-00 6.5L with DS4 model pump:

1994 - 2000 6.5L Diagnostics on PDF

To properly diagnose a 6.5L vehicle with the DS model pump you will need a scan tool. The 1994 and 1995 are OBD1 and the 1996 through the 2000 model year is OBD2, so the diagnostic codes are different depending on the year range.

LOW POWER
1. Low or no fuel supply pump pressure
2. Dirty fuel filter
3. Wastegate control solenoid

WHITE SMOKE
1. Low or no fuel supply pump pressure

BLACK SMOKE
1. Dirty air filter
2. Waste gate control solenoid failure, or low vacuum.
3. Worn injectors (excess carbon on the nozzle tips)
4. Low or no fuel supply pump pressure
5. If this occurred after the plenum chamber (intake) was removed, check the EGR tower gasket, if not seated EGR gases enter the engine unrestricted and in excessive quantity.
6. Restricted exhaust system, if the vehicle has been “babied”, the cat will partially plug. Take the vehicle out for several full throttle accelerations to clear out the exhaust

HARD START HOT
1. If the complaint is a hard start after a hot soak, not a stalling condition then hard start, check for a minimum cranking speed hot of 200 rpm.

MISS
1. Worn injectors
2. If the engine was overheated, check for a head gasket problem, usually on the turbocharger side (usually #4 & #6).
3. See Misfire Codes further below.

NO START, DIES INTERMITTENTLY OR STALLING
This is often caused by a bad PMD (Pump Mounted Driver or Fuel Control Solenoid Driver); however it is unusual to have multiple failures of the PMD. A bad Fuel control Solenoid (part of the injection pump) can cause the same symptoms and codes. A bad EGR, EGR vent, wastegate control, and transmission solenoid are on the same quad driver circuit and can cause intermittent stalling.

Follow the trouble shooting below to help pinpoint a possible bad PMD.  (GM Bulletin #77-63-06A)

1. Check fuel system for air (check at fuel return from pump), supply pump pressure, and fuel filter condition.

2. Check the PCM and injection pump wiring harness for chaffing and/or loose terminals at the PCM connector, the 15 pin connector and the PMD connector. See the WIRE HARNESS CONNECTIONS section for more information.

3. Check all engine and vehicle harness grounds.

4. Check for loss of ignition voltage on terminal "D" at the fuel solenoid driver connection to the injection pump. Refer to ENGINE CONTROLS IN THE 1998 SERVICE MANUAL FOR ALL MODEL YEARS.

5. Verify that the condition is still present:
 A. If the condition is no longer present, the vehicle is repaired
 B. If the condition is still present, and there are active DTC’s set, go to step 6.
C. If the condition is still present, and there are NO active DTC’s set, go to step 7.

6. For active DTC’s 35 or P1216, refer to Engine Controls in the 1998 Service Manual for all model years. If the DTC diagnostic table flow chart directs you to replace the injection pump, replace the PMD (Pump Mounted Driver) which is also called the Fuel Solenoid Driver. Go to step 9.

7. For stall condition, disconnect the Optical Sensor (Encoder Sensor) and operate the engine in back up fuel mode (you will experience and extended crank time during engine start, up to 15 seconds). A bad noise suppression harness or no noise suppression harness can also cause a stalling condition. If the condition is still present replace the PMD only. Go to step 9.

8. For a no start condition, check injection pulse width (94-95) or C-Time (96-2000 Fuel Solenoid Closure Time) with a scan tool, while cranking the engine (maintain minimum cranking speed 100 rpm cold and 200 rpm hot). If C-Time is 1.95ms (94-95) or 0.01ms (96-2000) replace the PMD. Go to step 9.

9. Replacing the PMD (Fuel Solenoid Driver):
 The PMD must be mounted to a “heat sink” of some kind. Stanadyne (Injection Pump Manufacture) states that the PMD must be mounted to the injection pump with the heat pad underneath it. In order to mount the PMD to the injection pump you must remove the intake manifold.
 If you don’t want to remove the intake manifold, you could purchase a remote mount kit such as the BD remote mount kit, and an aftermarket PMD. This would allow you to replace the PMD without removing the intake manifold.
 Stanadyne has finally come out with a new PMD it is completely redesigned from the original PMD. Since the wire harness connections are different as well as the calibration resistor, the intake manifold must be removed in order to replace the PMD, because the wire harness between the PMD and the Fuel Control Solenoid will have to be replaced.

Removing the PMD requires a T15 TORX bit. Replace the heat transfer pad and use snap ring pliers to remove the calibration resistor. Install the calibration resistor into the new PMD.

 If the calibration resistor is damaged, there is an identification number on it (1 through 9) and we have them available.

IMPORTANT: IF THE FUEL SOLENOID DRIVER CALIBRATING RESISTOR IS MISSING, DTC 56 (1994 1995) OR P1218 (1996-1998) WILL SET.

 INSTALL FUEL SOLENOID DRIVER: Align the mounting screws on the PMD with the holes on the injection pump (or on the remote mount PMD heat sink) Torque the mounting screws to 23 LB-IN.

IMPORTANT: DO NOT INSTALL THE FUEL SOLENOID DRIVER WITHOUT A NEW HEAT TRANSFER PAD. DO NOT REUSE A HEAT TRANSFER PAD. USE A NEW HEAT TRANSFER PAD ONLY. THE HEAT TRANSFER PAD IS REQUIRED TO PREVENT RAPID FAILURE OF THE FUEL SOLENOID DRIVER FROM OVERHEATING.

NOTICE: DO NOT OVER TIGHTEN FUEL SOLENOID DRIVER MOUNTING SCREWS. DAMAGE TO THE FUEL SOLENOID DRIVER WILL RESULT.

For Other Starting Issues, Check the high resolution signal, cam signal (from the injection pump) and crank signal.

X = good signal, 0 = no signal

Hertz Readings (HZ) while cranking and at idle

EGR
Light duty engines utilize an EGR system to help the engine meet emissions. The EGR flow calculation on some models uses the MAF sensor. If there are any “air intake leaks” either MAF or EGR codes can set. A missing or improperly sealing EGR tower gasket can cause either or both codes to set.
   Low or no vacuum from the vacuum pump can also cause EGR codes to set. A missing EGR tower gasket can cause a MAF low code to set, along with excessive black smoke, because it is pulling exhaust gases instead of clean air through the air filter.
 Failure to remove the block off plates from the intake manifold gaskets for a light duty engine can cause EGR codes because there will be no exhaust gases getting to the EGR valve.

FUEL SUPPLY PUMP
The fuel supply pump operates during cranking and after the engine oil pressure comes up. The supply pump is driven from a relay on the firewall or in the under hood fuse/relay center. The engine oil pressure sensor also includes a switch to operate the supply pump once engine oil pressure comes up after starting.
   The fuel supply pressure should be between 5-7 psi at idle. Test the pressure at the fuel filter drain at the front of the engine near the coolant crossover. Be aware that this is a pressure test on the dirty side of the fuel filter and if the filter is dirty the actual supply pressure to the injection pump will be lower.
  If the fuel supply pressure is zero, remove the fuel supply pump relay and jump #30 & #80 connector, this will send power to the supply pump with the ignition on. If you have good supply pressure now, then the most likely cause is a bad oil pressure sending switch.
 Low fuel supply pressure can cause DTC 17 (P0370)and 18 (P0251) to set due to aeration in the fuel, after all it is an optical sensor and it can’t see through an air fuel mix.

MISFIRE CODES
Misfire codes are handled differently for different years. Some misfire codes go by firing number order, in other words a misfire code for #2 would be #8 cylinder because it is the #2 cylinder in firing order. Check the service manual for the year you are working on.
 Firing order is

INJECTORS
The injectors on the 6.5L are usually only good for about 100,000 miles. They get a lot of carbon blown up inside of the nozzle tip. This results in poor atomization and poor spray patterns.

PMD (pump mounted driver)
The pump mounted driver gets 12 volt power when the key is on from a fuse in the _____
The PCM then sends a signal to the PMD to close the fuel control solenoid. When the fuel control solenoid closes it sends a signal back to the PMD and that is relayed to the PCM. The response time of the closure signal is called C-time.
  C-Time should change when the engine is accelerated or decelerated. A fixed C-Time can indicate a bad Fuel Control Solenoid. If the C-Time is erratic when the engine RPM is stable then this usually indicates a bad PMD. See Wire Harness Testing for other possible problems.

ENCODER SENSOR
If you have a no start condition, disconnect the encoder (optical) sensor and crank the engine for 15-20 seconds. If the engine starts then the problem is with the optical sensor.
The encoder sensor has to be able to see through the fuel inside the pump, if there is any air in the fuel it can cause trouble codes to set. Dirty fuel, SVO, no fuel supply pressure (air in system) or dyed fuel can all cause a problem with the encoder sensor “reading” the windows in the cam disk. There are 8 windows in the low resolution circuit and 512 windows in the high resolution circuit. In on minute at idle the high resolution circuit needs to read about 180,000 windows, in order to not set a code.

TDC OFFSET LEARN
The pump to engine timing must be set with a scan tool. You need to do the TDC offset learn procedure in order to set base pump to engine timing.

TURBOCHARGER
The turbocharger on the 6.5L EFI engine has a wastegate actuator that is controlled by vacuum. The wastegate actuator on the 94-2000 turbo does not have a spring, when no vacuum is applied the wastegate will “flop” back and forth. If the wastegate actuator holds a vacuum and it moves freely back and forth then there is nothing wrong with the wastegate actuator. A turbo boost problem and DTC78 (P0236) is normally caused by low vacuum (need 20 inches HG) or a bad wastegate control solenoid.
 To inspect the turbo, remove the inlet hose from the compressor inlet and make sure the turbo spins freely and that the compressor wheel does not rub on the housing when pushed to the side. Some side play is normal, because the bearings “float” on oil from the engine when the oil pressure is up.
 The turbocharger pulls crankcase fumes from the engine through the CDR valve. It is normal for the turbo to discharge oil from the compressor housing. You have to determine if you have more oil coming out versus going into the compressor housing. A plugged air filter or bad CDR valve can cause excessive oil to be pulled out of the engine and discharged from the turbo back into the intake. If the silicone hose connecting the compressor discharge is not sealed with a minor amount of silicone sealant than the hose connection will weep oil past the hose.

WASTEGATE CONTROL SOLENOID
The wastegate (WG) control solenoid controls the amount of vacuum going to the wastegate actuator on the turbocharger. The WG solenoid is controlled via a pulse width modulated signal from the PCM.

WIRE HARNESS TESTING
Poor electrical connections or wiring can cause most intermittent problems. Perform a careful check of the suspected circuit for the following:
Inspect and ensure the integrity of all related wiring harness connectors. If the wiring harness connectors are not properly put together or engaged before they are locked together, numerous types of conditions may occur. This may include many intermittent symptoms and DTC codes.
The first step in any type of electrical diagnosis is that a visual and physical inspection be completed of the wiring harness connectors for integrity. Many times, the vehicle may be repaired just by disconnecting and reconnecting the connectors. As with all repairs to wiring harness connectors and terminals, a pin test of the terminals within the connector should be performed. A pin test is performed by inserting the proper size terminal test tool (not a paper clip), into the terminal to determine whether or not the terminal is making good contact, or whether it has been damaged from prior improper connection, multiple connections or lack of connection.

COMMON CODES
Note; multiple codes can set for just one fault, as if the other codes wanted to come to the party. On an OBD2 system use the Tech 2 scan tool to determine which code set first and under what condition, A DTC17 (370) can trip a DTC18 (P0251), a DTC18 can trip a 19 (P0335) and a DTC19 can trip a DTC35 (P1216) or DTC36 (P

DTC17 (P0370) high resolution circuit fault can be caused by aeration in the fuel from a plugged fuel filter or low fuel supply pump pressure.

DTC18 (P0251) Pump cam reference error

DTC19 (P0335) crankshaft position reference error

DTC34 (P0216) injection timing stepper motor, watch the stepper motor and make sure it retracts when activating TDC learn.

DTC35 (P1216) fuel solenoid response time too short, less than 1.2 ms or .75ms on later years.

DTC36 (P1217) fuel solenoid response time too long, more that 2.5 ms, can be caused by a weak fuel control solenoid.

DTC56 (P1218) injection pump calibration resistor error. Usually is caused by a missing resistor, and this codes sometimes only sets after attempting TDC offset learn.

DTC78 (P0236) turbo boost performance, this is usually caused by a bad wastegate control solenoid or low vacuum.

DTC84 (P1125) APP can set if foot is on throttle and brake when key is turned on.

DTC88 (P1214) TDC offset error, the pump to engine timing must be within plus/minus 2 or 2.5 degrees when doing TDC offset learn or this code will set. This code could also set if the starter was used to crank the engine over while installing the injection pump, this will sometimes partially shear the crankshaft timing chain gear key.