DIESEL PERFORMANCE FAQ
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We will need: Vehicle make, model, year, automatic or manual transmission and what you are towing. We will help you select what best fits your needs.
We have installed performance products and exhaust brakes on our own vehicles.
We know what works, we know what lasts.
Diesel performance enhancements are very easy to achieve – add more FUEL, but what does that cause? In order to keep exhaust temperatures (pyrometer temp.) under control, you have to improve airflow. Vehicle models are different. For example, 1994-1997 PowerStrokes have an air flow restriction in the turbo downtube, which needs to be replaced. In 1999-2003 models, the restrictions are in the muffler, which needs to be replaced.
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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 POWERSTROKE:
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 |
| 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 |
| 1994-1997 | IDLE | WOT in neutral | HARD ACCELLERATION |
| ICP | 575-600 | 1300-1400 | 2450-2700 psi |
| IPR | 11-14% | 18-21% | 35-40% |
| 1999-2003 | IDLE | WOT in neutral | HARD ACCELERATION |
| ICP | 475-490 | 1100-1200** | 2450-2750 psi |
| IPR | 9-11% | 18-21% | 35-40% |
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
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.
94-98 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:
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:
Low Power/Miss -
1. 6.5L - The electric fuel supply pump gets power, when the engine is
running, through the oil pressure-sending switch. When the engine is running
you need 7psi of fuel supply pressure (top at filter drain fitting at front of
engine by the coolant crossover). If no pressure, bypass fuel pump relay. If
you get pressure, then the oil pressure switch could be bad, and if no
pressure still, then the fuel supply pump could be bad.
Low Power/SES Light on/Black Smoke -
1. 94-00 6.5L - Code 78, wastegate solenoid
fault - Most likely cause would be the wastegate control solenoid. They fail
quite often on vehicles with over 100,000 miles on them. The turbocharger wastegate actuator
itself very seldom ever fails, regardless of what repair manuals/online diagnostic aides
indicate.
Misses -
1. 94-00 6.5L DS model electronic pump - There have been many updates to the
first pump that came out to improve longevity and reliability (we do all the
updates). A common problem would be a “fish bite” surge at cruising speed.
First, try removing the plastic engine cover and leaving it off. It tends to
trap heat. The PMD (pump mounted driver) is sensitive to heat and can cause
this problem if “overheated”.
2. Removing the plastic cover from the top of the engine will help reduce the heat build up
in the PMD and prolong the life of the PMD.