Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
Ok, first thing, you shouldn't allow the starter to get too hot while trying to crank and start an engine. 10 seconds is enough, if it doesn't start after 10 seconds then turn back back to off and wait a few seconds for the starter to cool down or you may damage the starter.
Second, what color smoke is coming out the tailpipe when it first starts?
Third, when it trys to start and back-fires is it back-firing out the intake or the exhaust?
Forth, the reason it is hesitating when trying to start is either the timing is off or the starter is getting too hot.
Fifth, ok, I do see that the back-fire is from the throttle body, is it a loud pop with fire or just a puff with a white mist?
Sixth, the rotor will turn a little by hand that is normal as it is connected to the spring and weights, but it is starting to sound like the timing is off. How many miles is on this engine?
Seventh, backfiring through the throttle body is usually too lean a mixture, the timing off or a blown headgasket or intake valve remaining open, too rich and it would backfire out the tailpipe and you said it woudln't even start with staring fluid so I am saying the fuel injectors are probably ok since starting fluid wont even start it. That leaves spark and\or timing and of course compression. A blown head gasket and it should still start but run bad. Try a spark test to see if you are getting spark. Check a spark plug wire than if no spark check it from the coil.
You can make a test plug with a new spark plug and some wire, a mini hose clamp and an alligator clip. First open the spark plug gap to around 0.075" and strip both ends of a 16 gauge wire about 4 foot in length. Attach the mini hose clamp around the threads of the spark plug cause that is a ground and secure it with the mini hose clamp with the bare wire end in between to make a good connection. Next, take the other end of wire and secure to an alligator clip.
Now, you have a test plug. Remove any spark plug boot you want and insert your test plug onto the spark plug wire end you just pulled off and ground the alligator clip. Lay the spark plug in some shade somewhere under that hood and then crank the engine and look for spark. It should crackle with sound and should be blue but red is ok, orange is a little weak. If it can jump that 0.075" gap you should have no problem igniting an engine.
You can also use that to check coils on some vehicles.
Last but not least, it sounds like a timing issue. Time the engine. If you can't get the engine started to time it, at least point the timing light down at the mark while it is cranking to see if it is even close. If not loosen the distributor and turn it to where it is close enough to get it started and then use the timing light again.
If, you still cant get it started let me know and we will check the timing chain. But just for starters you will have to remove the # XXXXX spark plug stick something thin into the cylinder and turn the crank with a socket on the front bolt untill the piston is at TDC on the compression stroke then look down at the timing mark on the damper, if it not on 0 then it jumped. Also, if you do get it started you can check the wear of the chain. Rev the engine untill you get to the most advance by the mechaniacl advance as told by flashing your timing light down on the mark, then raise the rpm 500 more rpm's than 1,000 more rpm's and back and forth a few times and watch the timing mark, it should not move more than a few degrees or the chain is worn. What that does is throw the slack in the chain from 1 side to the other.
Also, once you get it started and if it still runs with a miss do a cylinder balance test.
First of all you will need a 12-volt test light and about 8-12 inches of neoprene vacuum hose. The vacuum hose will conduct electricity cause it is carbon based, use an ohmmeter if you aren't sure and see if the vacuum hose you have will conduct.
Now, cut off the same # XXXXX cylinders you have in small equal lengths of the vacuum hose. 1-2 inches will do fine. The small diameter kind like to carburetors, etc will work as long as they fit over the distributor cap tower connection.
Now, mark all your spark plug wires at the cap and remove them all. Put those short pieces of vacuum hose on the distributor cap connections and shove the other end of the vacuum hose into the spark plug wire boot until it makes a good connection.
Now connect your 12 volt test ground clip to a ground and start the vehicle. With the engine running touch the 12 volt test light to each of the vacuum hose 1 at a time and listen for the cylinder to short out and die and drop in r.p.m. They should all be about equal. If 1 or a few don't drop or do anything than you have your dead cylinder there.
Finnally, I really dont think a lean fuel mixture will cause this unless it is a massive leak. Check the brake booster vacuum hose and make sure that is hooked up.
Get back to me and let me know how things are going!
Fuel pump is good for sure at least to the fuel rail port. Also, nothing is leaking down at the throttle body when I used mirror to look down while starting the car. Color is yellowish orage looking using spark plug tester. I did change iginition coil. It has only one coil ports so i didn't know how to test the coil. So i just changed it. I confirmed that it's getting all 8 spark plug using test lights. I used a can of starter fluid. It back fired out of throttle body if I sprayed too much. However, couple of occasion it sounded as if i quieted and engine started and died off if I sprayed right amount and let the throttle body door open. I have lack of experiecing in adjust timing but i will read up on it and attempt to do so if everything else fail. However, I am thinking it's more matter of fuel injector issue since it almost almost started with starting fluid. I have no easy way of telling if injectors are clogged without tearing things apart. Also, since it's electronically controlled, how do i know what controlls fuel injectors are failling instead of fuel injectors being clogged up. I need to do fuel test again to see how much it drops when I turn ignition off right? That tells me something about fuel injection status? If not, my next move is attempt to take it apart and see the injectors themselves. What do you think?
I am leaning more toward fuel injection problem since it almost almost started with right spray of starter fluid.
2002 Chevrolet Express 3500
PATH: Engine Electrical > Distributor Ignition System > Adjustments
Ignition timing is preset and cannot be adjusted. Ignition timing is controlled by the Powertrain Control Module (PCM).
On V6 motors the distributor is located in a fixed, non-adjustable position. DO NOT attempt to rotate the distributor otherwise damage may result.
On V8 engines the distributor can be rotated for proper alignment of the rotor to the cap. The engine base timing is not adjustable by rotating the distributor.
Prior to starting this symptom test routine, inspect these underhood items:
Check battery charge and condition, starter current draw.
Verify the starter relay operation and that the engine cranks (turns over).
Verify the check engine light (MIL) operation - if it does not activate, check the PCM power and ground circuits, and check for 5v supply at the MAP or TP sensor.
Check Air Intake system for restrictions (inspect air inlet tubes, air filter for dirt, etc.).
Check the status of the Smart Key Immobilizer System (SKIM) with the Scan Tool.
Test 1 Chart
Step Description: No Start Condition Only Check battery cables, state of charge. If the engine does not rotate, inspect for a locked engine (hydrostatic lockup condition). Does the engine crank normally?
Go to Step 2.
Repair the fault in the battery, starter, or Base Engine. Retest for the symptom when all repairs are done.
Step Description: Check the Fuel System Verify that the pump operates at key on. Check the fuel pump relay operation. If the relay does not operate, check for blown fuse. Inspect pump for a leak-down condition Test fuel pressure, volume and quality. Test the operation of the fuel regulator. Are there any faults in the Fuel system?
Make needed repairs.
Go to Step 3.
Step Description: Check the Ignition System Inspect ignition secondary components for damage (look for rotor "punch-through"). Inspect the coils for signs of spark leakage at coil towers or primary connections. Check the spark output with a spark tester. Test Ignition system with an engine analyzer. Are there any faults in the Ignition system?
Make repairs to the Ignition system. Then retest the symptom.
Go to Step 4.
Step Description: Check the Exhaust System Check Exhaust system for leaks or damage. Check the Exhaust system for a restriction using the Vacuum or Pressure Gauge Test (e.g., exhaust backpressure reading should not exceed 1.5 psi at cruise speeds). Are there any faults in the Exhaust system?
Make repairs to the Exhaust system. Then retest the symptom.
Go to Step 5.
Step Description: Check the MAP Sensor Disconnect the MAP sensor and attempt to start the engine. Does the engine start and run normally?
Replace the MAP sensor. Retest for the symptom when repairs are completed.
Go to Step 6.
Test 1: No Start, Hard Start Condition (Continued)
Test 1 Chart (Continued)
Step Description: Check for a Hot Engine Check for signs of an engine overheating condition related to a Hard Start Symptom. Does the engine appear to be overheated?
Make the repairs to correct the hot engine and then retest for the symptom when done.
Go to Step 7.
Step Description: Check ECT Sensor PID Connect a Scan Tool and turn the key to on. Read the ECT sensor (compare to chart). Has the ECT sensor shifted out of range?
Replace the ECT sensor. Then retest for the symptom when all repairs are completed.
Go to Step 8.
Step Description: Check the PCV System Inspect the PCV system components for broken parts or loose connections. Test the operation of the PCV valve. Are there any faults in the PCV system?
Repair the PCV system. Refer to the PCV system tests. Retest the symptom when all repairs are done.
Go to Step 9.
Step Description: Check the EVAP System Inspect for damaged or disconnected EVAP system components. Inspect for a fuel saturated charcoal canister. Are there any faults in the EVAP system?
Refer to the EVAP system tests in this manual. Retest for the symptom when all repairs are completed.
Go to Step 10.
Step Description: Test the Base Engine Check the engine compression. Test valve timing and timing chain condition. Check for a worn camshaft or valve train. Check for any large intake manifold leaks. Are there any faults in the Base Engine?
Repair the Base Engine. Refer to the Base Engine Tests. Retest symptom when done.
Return to Step 2 to repeat the test steps in this series to locate and repair the "No Start, Hard Start" condition.
Surprising no computer codes stored. No fuse were burned out. I did read with a OBD II reader. Although I saw black spark plug which I installed just couple of days ago, I am not convienced that right amount of fuel is coming out of fuel injectors. I smell that much of gas smell even though i keep the throttle body open and keep pumping gas.
I wish there is some ways to tell if fuel injectors are working at least.
If its a throttle body you should just be able to look at them. You said though it wasn't even starting with starting fluid. You might want to take out a spark plug and smell it, maybe they are gas fouled and the engine is floaded. You dont have to pump the gas pedal on fuel injection.
I did notice you said rail. You may want to purchase a noid light kit, that way you can check if all the injectors and getting a signal.
OEM/6 pcs. noid light set
Also, I found a tsb on fuel injectors.
#03-06-04-030F: Various Driveability Symptoms Due to Clogged
Fuel Injectors, MIL/SES DTCs P0171, P0172, P0174, P0300,
P1174, P1175 (Clean Fuel Injectors and/or Perform Injector
Test With AFIT - CH-47976) - (Dec 10, 2007)
This bulletin is being revised to update the model year to 2008. Please discard Corporate Bulletin
Number 03-06-04-030E (Section 06 -- Engine/Propulsion System).
Some customers may comment on any of the following various driveability symptoms:
Due to various factors, the fuel injectors may become restricted. Extensive testing has demonstrated that fuel
related issues are the cause of clogged injectors. At this point, no specific fuel, fuel constituent, or engine condition
has been identified as causing the restriction. The restriction causes the engine to operate at a lean air fuel ratio.
This may either trigger the MIL to illuminate or the engine to develop various driveability symptoms.
Fuel injector restrictions, deposits can be cleaned on the vehicle using the following procedure. Under NO
circumstances should this procedure be modified, changed or shortened. As a long term solution, and to prevent
reoccurrence, customers should be encouraged to use Top Tier Detergent Gasoline . For further information on Top
Tier detergent gasoline and fuel retailers, please refer to the following Corporate Bulletin Numbers:
Notice: GM UPPER ENGINE AND FUEL INJECTOR CLEANER is the only injector cleaning agent approved for use with
General Motors fuel system components. Other injector cleaners may cause damage to plastics, plated metals or
bearings. General Motors has completed extensive laboratory testing of GM Upper Engine and Fuel Injector Cleaner,
and can assure its compatibility with General Motors fuel system components, as long as the cleaning procedure is
Subject: Various Driveability Symptoms Due to Clogged Fuel Injectors, MIL/SES
DTCs P0171, P0172, P0174, P0300, P1174, P1175 (Clean Fuel Injectors
and/or Perform Injector Test With AFIT - CH-47976)
Models: 2000-2008 GM Passenger Cars and Light Duty Trucks (Including Saturn)
2003-2008 HUMMER H2
2006-2008 HUMMER H3
2005-2008 Saab 9-7X
with 2.0L, 2.2L, 2.4L, 2.8L, 3.1L, 3.4L, 3.5L, 3.8L, 3.9L, 4.2L, 4.3L, 4.8L, 5.3L, 6.0L, 6.2L
or 8.1L Engine (VINs X, F, D, 4, 5, T, 8, J, E, H, L, 6, K, 1, 2, R, W, S, X, V, T, M, N, U, H, Y,
8, G -- RPOs LNF, L61, LN2, L43, LD9, LK5, LG8, LA1, LX5, LX9, LZ4, LZE, L52, L36, L67,
L26, LZ9, LZ8, LGD, LL8, LU3, LR4, LM7, LH6, LQ9, LQ4, LS2, L76, L92, L18)
and MULTEC® 2 Fuel Injectors
Injector Cleaning Procedure
The following tools, or their equivalent, are required:
Active Fuel Injector Tester (AFIT- CH-47976)
Some dealers may not have an Active Fuel Injector Tester (AFIT- CH-47976). Dealers can contact 1-800-GMTOOLS
(1-800-468-6657) to order an AFIT- CH-47976. Dealers still can test the fuel injectors without an AFIT.
Refer to Fuel Injector Diagnosis (w/ J 39021 or Tech 2®) in SI.
Important: As mentioned in the AFIT User Guide, vehicles that are not listed in the AFIT menu can still be tested
with the AFIT. Depending on the model, it may be possible to enter the previous model year and proceed with
testing using the DLC connection. If this is not possible on the model that you are working on, it will be necessary
to use the direct connection method outlined in the AFIT User Guide (See Pages 17-31).
General Motors recommends that the Active Fuel Injector Tester (AFIT) be used in testing fuel injectors. If the SI
diagnostics do not isolate a cause for this concern, use the Active Fuel Injector Tester (AFIT - CH-47976) to
perform an "Injector Test" as outlined in the AFIT User Guide.
The AFIT "Injector Test" measures the flow characteristics of all fuel injectors, which is more precise when
compared with the standard Tech 2® fuel injector balance test. As a result, the AFIT is more likely to isolate the
cause of a P1174 DTC (for example: if it is being caused by a fuel injector concern).
The CH-47976 (Active Fuel Injector Tester - AFIT) can also be used to measure fuel pressure and fuel system leak
down. Also, as mentioned in the P1174 SI diagnosis, if the misfire current counters or misfire graph indicate any
misfires, it may be an indicator of the cylinder that is causing the concern. Refer to Fuel Injector Diagnosis (w/CH-
47976) in SI for additional instructions.
To access the training video on AFIT, take the following path at the GM Training Website:
1. After logging into the gmtraining.com website, choose the link on the left side of the page titled "web video
2. Then choose "technical."
3. Next, within the search box, type in September course number "10206.09D.
4. This will bring up a link with this course. Scroll through to choose "feature topic."
5. At this point, the seminar can be chosen to view or the video related to the AFIT.
Additional training is available from the gmtraining.com website. Please see TECHassist 16044.18T2 Active Fuel
Injector Tester and also see 16044.14D1 GM Powertrain Performance for more information on GM Upper Engine
and Fuel Injector Cleaner.
Also, dealers can now download software updates for the AFIT at GM Dealer Equipment (GMDE) on the web at
To access the training video on AFIT, take the following path at the GMPro LMS Training Website:
1. After logging into the <www.gmprocanada.com> website, choose the link on the left side of the page titled
2. Then choose "Catalog Search."
3. Next, within the search box, Select Course Number - Contains - "T" then select search.
4. This will bring up a list of TECHassist courses. Scroll through to choose "Active Fuel Injector Tester" and
5. At this point, a new window will open and the program can be Launched.
Additional information can be found on AFIT (June 2006 Edition) and GM Upper Engine and Fuel Injector Cleaner
(November 2006 Edition) in Techlink. To access the articles, take the following path:
1. Go to GM DealerWorld (U.S.) or the GM infoNET (Canada).
2. Click on the Service Tab in DealerWorld (GM infoNET for Canada).
3. Click on the GM Techlink Hyperlink.
4. Click on the Archives Hyperlink at GM Techlink.
Notice: GM UPPER ENGINE AND FUEL INJECTOR CLEANER is the only injector cleaning agent recommended. DO
NOT USE OTHER CLEANING AGENTS AS THEY MAY CONTAIN METHANOL, WHICH CAN DAMAGE FUEL SYSTEM
COMPONENTS. Under NO circumstances should the GM Upper Engine and Fuel Injector Cleaner be added to the
vehicle fuel tank.
Do not exceed the recommended cleaning solution concentration. Testing has demonstrated that exceeding the
recommended cleaning solution concentration does not improve the effectiveness of this procedure.
Important: Vehicles with less than 160 km (100 mi) on the odometer should not have the injectors cleaned. These
vehicles should have any out of specification injectors replaced.
1. For 4, 5 and 6 cylinder engines, empty two of the 30 ml (1 oz) reservoirs of the GM Upper Engine and Fuel
Injector Cleaner container into the J 35800-A - Injector Cleaning Tank then add 420 ml (14 oz) of regular
unleaded gasoline. If you are using any other brand of cleaning tank, you will need a total of 60 ml (2 oz)
mixed with 420 ml (14 oz) of regular unleaded gasoline.
2. For 8 cylinder engines, empty two of the 30 ml (1 oz) reservoirs of the GM Upper Engine and Fuel Injector
Cleaner container into the J 35800-A - Injector Cleaning Tank then add 420 ml (14 oz) of regular unleaded
gasoline. If you are using any other brand of cleaning tank, you will need a total of 60 ml (2 oz) of Upper
need to be repeated for a second time for an 8 cylinder engine (8 cylinder engines receive 960 ml total fluid -
120 ml (4 oz) of Upper Engine and Fuel Injector Cleaner and 840 ml (28 oz) of gasoline.
3. Be sure to follow all additional instructions provided with the tool.
4. Electrically disable the vehicle fuel pump by either removing the fuel pump fuse or the fuel pump relay and
disconnecting the oil pressure switch connector, if equipped.
5. Turn the ignition to the OFF position.
6. Relieve fuel pressure and disconnect the fuel feed and return lines at the fuel rail. Plug the fuel feed and
return lines coming off the fuel rail with J 37287, J 42873 or J 42964 as appropriate for the fuel system.
7. Connect the J 35800-A to the vehicle fuel rail.
8. Pressurize the J 35800-A to 510 kPa (75 psi).
9. Start and idle the engine until it stalls, due to lack of fuel. This should take approximately 15-20 minutes.
10. Turn the ignition to the OFF position.
11. Disconnect the J 35800-A from the fuel rail.
12. Reconnect the vehicle fuel pump relay and oil pressure switch connector, if equipped.
13. Remove the J 37287, J 42873 or J 42964 and reconnect the vehicle fuel feed and return lines.
14. Start and idle the vehicle for an additional two minutes to ensure residual injector cleaner is flushed from the
fuel rail and fuel lines.
15. Pour the entire contents of GM Fuel System Treatment Plus (P/N 88861011 [in Canada, P/N 88861012]) into
the tank and advise the customer to fill the tank.
16. Review the benefits of using Top Tier Detergent gasoline with the customer and recommend that they add a
bottle of GM Fuel System Treatment Plus to the fuel tank at every oil change. Regular use of GM Fuel System
Treatment Plus should keep the customer from having to repeat the injector cleaning procedure.
17. Road test the vehicle to verify that the customer concern has been corrected.
November 2006 Techlink Article.
Part Number Description Qty
* Only 1/8 of the cost may be claimed for 4 and 6 cylinder engines and 1/4 of the cost for 8 cylinder engines.
Warranty Information (excluding Saab U.S. Models)
For vehicles repaired under warranty, use:
Warranty Information (Saab U.S. Models)
88861802 GM Upper Engine and Fuel Injector Cleaner 473 ml (16 oz) Container (U.S.) 1*
88861804 GM Upper Engine and Fuel Injector Cleaner 473 ml Container (Canada) 1
88861011 Fuel System Treatment Plus 591 ml (20 oz) Container (U.S.) 1
88861012 Fuel System Treatment Plus 591 ml Container (Canada) 1
Labor Operation Description Labor Time
4 Cylinder Engine 0.8 hr
5 Cylinder Engine 0.7 hr
6 Cylinder Engine 0.7 hr
8 Cylinder Engine 0.9 hr
**Add: Diagnostic Time 0.0-0.3 hr
* This labor operation number is XXXXX bulletin use only. This number will not be published in the Labor Time
**A total diagnostic time equal to the time allowed for cleaning, J5645, may be claimed for performing the
injector diagnosis procedure.
24211 71 0 01 01
-- -- -- -- --
24211 71 0 01 05 0.7 hr*
24211 71 0 01 05 0.9 hr*
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles,
or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job
properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for
information on whether your vehicle may benefit from the information.
You may want to check the coil, too.
Make sure the ignition switch is OFF .
1. Tag and disconnect the wires from the ignition coil.
2. Using a digital ohmmeter set on the high scale, probe the ignition coil as shown in Step 1 of the accompanying illustration.
Fig. Ignition coil testing points
3. The reading should be infinite. If not replace the coil.
4. Using the low scale of the ohmmeter, probe the ignition coil as shown in Step 2 of the accompanying illustration. The reading should be 0.1 ohms, if not replace the coil.
5. Using the high scale of the ohmmeter, probe the ignition coil as shown in Step 3 of the accompanying illustration. The reading should be 5k-25k ohms, if not replace the coil.
6. Reconnect the wires to the ignition coil.
CPK resistence reads at 5.2 at 200K OHM scale so it's 520 Omhs?
I hooked up fuel pressure gauge again and after couple of ignition on position and off, suprisingly, the van started. I didn't want to idle it too long with fuel pump guage hook up so I turned off the engine. I did start relatively easy when it did start. I didn't have to crank it too long. The pressure guage didn't seem to drop below 50 psi. After I turned off the car and when the car didn't start, the PSI level was up again about 65psi. Also I could hear fuel pump in the back.
I also checked voltage feeding into ICM and it was slightly below 12v. Now the van of course won't start. Back to same old thing. It will keep on turning over and making usual sound but won't ignite. Another theory I heard was the starter motor perhaps drawing too much power? I don't think that's the case since the starter motor turns over strong. Do you think I need to replace ICM first or start checking fuel injectors?
Actually I think 5.2 at 200k scale is 1040 k ohms. If the starter motor was drawing too much power or amps from the battery it would crank slow. Sorry that picture never showed up for checking the coil. Do yourself a favor, take the coil into an autoparts store, they will check it for free and get a new set of spark plugs. They may be gas fouled. Unless you just want to use some carb cleaner and remove all the spark plugs and clean them up. Before removing all the spark plugs crack each spark plug loose and loosen a few turns and disconnect the coil wire so it wont start and crank the engine over a few times to create pressure in the cylinders and blow any gas out. Then remove all the spark plugs clean or replace them recheck the gaps and reinstall. When and if you use starting fluid you only need like 2-3 medium squirts, if it don't start with that then the problem is most likely not fuel but spark. Recheck that coil.
Now I think I have narrowed down the problem somewhat. I have installed a new coil and an ignition control module (used one due to price, I have another one on the way, just in case if this one I just bought is bad). Still I wasn't able to start. It's a consistant sound of wanting to start and no start. No back fire from exhaust. I think that was due to spraying starter fluid.
I read dtc code again to see if it pickup anything and indeed it pickup something. I got P1345 which is CAM and CRANK position correlection is incorrect. In other words, I got timing related component problems. This van used to have a hard time starting before not starting at all. This might be the cause - timing issue. So I might need a CAM/CRANK sensors, or a distributor since there was a little bit of distributor slack if I hold it firmly and move it little bit. Also, I have to check and see if timing is correct first place. Distributor might worned out perhaps or reinstalled again? Crank position sensor is about $100 over here new. No used sensor available. For distributor, I need to buy a used distributor if I can. Crank position sensor is easy and quick but of course there is no guarantee. Which one do you think I should do do first?
Well, first of all if it's just the bushing in the distributor than I would just rebuild it with a $4 bushing. I am guessing that is what a bushing costs of course and knowing Gm nowadays it might be hard or slightly impossible to find.
Second, if there are any tests that you can perform first on the crank and cam sensor I would test them first. I was just reading a tsb earliar on something about a loose distributor. Now I have to find that. I dont think it was this post but who knows I read so much today. I'm assuming that distributor probably only goes in 1 way and the ecm actually controls the timing.
Camshaft Position Sensor
Crankshaft Position Sensor
#03-06-04-041A: Poor Engine Performance-Misfire,
Rough Idle, Stalls, Engine Cranks but Does Not Run,
SES/Check Engine Light On, DTC P0300 Set (Inspect
Distributor Ignition(DI) System Components, Replace
as Necessary) - (Jan 28, 2005)
This bulletin is being revised to delete a model and add information to subject and
inspection of distributor vent screens. Please discard Corporate Bulletin Number 03-
06-04-041 (Section 06 - Engine/Propulsion System).
Some customers may comment on poor engine performance and the Service Engine
Soon/Check Engine light being illuminated. Upon investigation, the technician may find DTC
This condition may be due to high levels of internal corrosion in the distributor, causing misfire,
rough idle, stall and Engine Cranks But Does Not Run. This corrosion is attributed to a lack of
airflow internal to the cap caused by the vent screens being clogged with debris.
Remove the vent screens and inspect the internal components of the Distributor Ignition
System using the procedure listed below. If the distributor base has to be replaced, the vent
screens will also have to be removed on the new distributor. If there is evidence of this internal
corrosion, replace the affected component. Refer to the appropriate procedure in the Engine
Controls sub-section of the applicable Service Manual.
Important: All of these inspections can be done on-vehicle.
1. 1. Inspect the distributor cap. You may notice a white residue on the cap walls. For higher
mileage occurrences, the interior of the cap may have changed to medium brown in color
2. 2. Inspect the distributor rotor. You may notice the presence of black streaks on the
Subject: Poor Engine Performance - Misfire, Rough Idle, Stalls,
Engine Cranks but Does Not Run, Service Engine
Soon/Check Engine Light Illuminated, DTC P0300 Set
(Inspect Distributor Ignition (DI) System Components and
Replace As Necessary)
Models: 2001-2003 Chevrolet Astro, Blazer, Express, S-10
2001-2003 GMC Jimmy, Safari, Savana, Sonoma
2001 Oldsmobile Bravada
with 4.3L, 5.0L or 5.7L Gas Engine (VINs W, X, M, R -- RPOs L35, LU3,
plastic surface. More typical evidence would be visible green spots on the copper surface
of the rotor segment.
3. 3. Inspect the distributor base. You may notice high levels of surface rust on the
distributor shaft or surface contamination on the sensor hold down screws.
4. 4. Inspect the distributor vent screens (1). If the vent screens are present, remove them
by using a plastic-handled, long blade awl or pick (2). Insert into the airflow vent screens
and pop them out. Refer to the figure for removal procedure. If the vent screens have
been removed from the base of the distributor, then check the airflow inlets for being
clogged with debris.
Parts are currently available from GMSPO.
Part Number Description
10452458 Cap, Distributor (V6)
10452457 Rotor, Distributor (V6 and V8)
93441559 Distributor (V6)
10452459 Cap, Distributor (V8)
93441558 Distributor (V8)
Operation Description Labor Time
J4360 Cap, Distributor - Replace
Use published labor operation
J4380 Rotor, Distributor - Replace
J4530 Distributor Assembly - Replace
To remove Distributor vent
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that
may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the
equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin
applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the
Did you ever have the distributor out?
All you can do is bring up the #1 piston up untill it is at tdc and then turn the distributor to align the rotor to the #1 on the cap. That may have been your problem the spark from the rotor was firing in bewteen terminals on the cap.
In case you have to set the distributor in again.
Engine Electrical > Distributor Ignition System > Distributor > Installation > 4.3L, 5.0L, 5.7L And 7.4L Engines >
4.3L, 5.0L, 5.7L And 7.4L Engines--------------------------------------------------------------------------------¦Timing Disturbed
Remove the No. 1 cylinder spark plug. Turn the engine using a socket wrench on the large bolt on the front of the crankshaft pulley. Place a finger near the No. 1 spark plug hole and turn the crankshaft until the piston reaches Top Dead Center (TDC). As the engine approaches TDC, you will feel air being expelled through the No. 1 cylinder spark plug hole. The timing mark on the crankshaft pulley should now be aligned with the 0 mark on the timing scale. If the position is not being met, turn the engine another full turn (360 degrees). Once the engines position is correct, install the spark plug.
Before installation, position the rotor so it points to the No. 2 terminal on the cap. As the distributor is lowered into the engine, the rotor will rotate clockwise and stop at the No. 1 terminal. This is the desired position.
Turn the rotor so that it will point to the No. 1 terminal of the distributor cap when it is fully seated in the engine.
Install or connect the following:
Distributor. It may be necessary to turn the rotor a little in either direction, in order to engage the gears.
If the distributor will not seat completely in the engine, remove the distributor and align the groove on the top of the oil pump drive shaft with a long screwdriver to match the tab on the bottom of the distributor shaft. Reinstall the distributor.
Tap the starter a few times to ensure that the oil pump shaft is mated to the distributor shaft.
Bring the engine to TDC again and check that the rotor is pointed toward the No. 1 terminal of the cap. If the marks are all aligned.
Hold-down bolt and tighten
Cap and fasten the mounting screws
Electrical connections and the spark plug wires
¦Timing Not Disturbed
Distributor, aligning the matchmarks are properly alignment
Distributor hold-down bolt
Electrical connector at the base of the distributor
Spark plug wires and coil leads
Negative battery cable
Number of Trips to Set Code: 1
OBD II Monitor Type: CCM DetailsIndicators: MIL Details
Trouble Code Conditions:
Engine started; and the PCM detected the CMP pulses missing at the relative position of the CKP pulses or the CMP signal was 15 degrees out of phase with CKP falling edge (7.4L V8).
CMP sensor is loose causing a variation in the sensor signal
Excessive free play in the timing chain and gear assembly
Incorrectly installed distributor - 1 tooth off in either advance or retard positions
Distributor rotor is loose on the distributor shaft, or hold down bolt is loose or missing
Perform the Camshaft retard offset test procedure
Ignition module has failed
TSB 61-65-60A contains a repair procedure for this code
I haven't taken it out. I am still lost I guess. I checked rotor cap and rotor and the rotor was point to #1 position of cap. So suppose it is not timing is not disturbed. How do i bring it to piston to TDC? Do I use by hand to rotate the distributor? If I close it and screw it and force it little bit by hand, the whole thing will move including cap, rotor, and distributor of course. I think I missed something here significant here.
I am not having a good luck. I went out and looked and looked and i could not find metal clip thing that haynes manual shows right top corner of vibration damper. I saw a groove on the vibration damper but i have no reference point where i can align this. Perhaps this piece was removed from somewhere else. Thus i need another method to bring this to TDC. Please help.
Ok, the groove in the damper is the timing mark, clean it off and if you can't see it that well take some brightly colored chalk and mark it.
That tang should be on the timing chain cover, you may have to look down from the top behind the water pump usually on the drivers side.
Firing order is correct. I actually started the van one time couple of days ago. Just one time. Before I was doing a tune up, it had a hard time starting the van. I will double check behind the waterpump and see. Before doing the tune up it had a fuel rich condition where a lot of white/black mixed smoke but lot like head gasket problem smoke when it first started van. A friend of mine looked at the van today and he said there is fresh oil around distributor and he thinks there is a vacuum leak. He thinks intake gasket is blown creating a vacuum leak. Therefore, the van wouldn't start. I have to check vacuum test to verify what he thinks. He also said that there is no timing reference metal thing because it's already timed and you are not supposed to change anything. I will double check the timing metal reference point around waterpump and see. Also, if doing a vacuum leak as a result of intake gasket proves it to be true, it will be beyond my scope to fix this problem myself since this is not my vehicle.
There isn't much vacuum while cranking if any at all. I already posted that the timing is factory set and can't be adjusted but you should still be able to check it. you might have to use a computer scan tool but I did see from some pictures at autozone all the timing chain covers had something built into them that looked something like to show where the timing should be. Take the distributor cap off and check it for oil and clean it. Black smoke is gas and white is usually coolant or tranny fluid. You can check for a vacuum leak but you would have to get it started first. Replacing a head gasket is not that difficult if you have tools and some time. If and when you do have to do head gaskets on a van or truck I like to let the air out of the front tires just untill the rims are about 1 inch off the ground so they don't cut into the tire. Makes it much easiar reaching over the grill. This is a long post, I dont know if you already answered this question but did you check the computer for any codes? It should still start even with a bad head gasket. At the worst an 8 cylinder would be running on 6 and it should still run. Do you have a compression tester?
Ok, just to recap. You are getting fuel but you think too much. You get spark but you think it is weak or out of time. It's possible if all those conditions were met all at the same time maybe it shouldn't start. A blown head gasket, weak spark and plus injector flooding. Did it happen all of a sudden or did it just get worse and worse untill one day it wouldn't start?