I don't know if this is legal or not but I need help with a 91 GMC pickup with a 5.7 v8.It starts great run dood but dies when put in gear. Also when you do get it running in gear it will stall at red lights and stop signs. It always starts right up though. Any help will be appreciated.Thats all I know right now as it is something I was consdering to buy for a beater.
Tank you
Fred

 

Might have some better luck in the off topic section. Good luck.

 

I'm still waiting for a reply on the GMC forum..concerning an issue with my C5.

 

We had a 96 Olds Cutlass, 3.4 L dual overhead cam, that did the same thing only after it got up to operating temp. Turns out it was a clogged fuel injector that would cause it to stall out at lights and slow speeds, it would always start right back up. Kinda hard to diagnose with out actually being there though.

 

M6 C5 sounds familiar.You think some injector cleaner would help.What did you do for your Olds?
Thank you
Fred

 

Its a possibility that it would help but from what I have heard about injector cleaner is that it does not do a very good job and the only way to actually clean them is to pull them out of the car and if im not mistaken clean them with brake fluid but there are some that can not be cleaned like in my dads old sonoma which had the 4.3 vortec.
We actually never tried any injector cleaner or anything on it and the mechanic who works on all of our vehicles said they needed replacing but my dad did not want to put any more money into the car so we just left it as it was, just had to bump it into neutral and start it back up.

 

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memmer

Sounds like your having a security related issue. Use a scanner and read the DTCs and see if there are any. If you dont have one go to Autozone and use theres

If you have a VATs related issue, that issue will happen. If your key has a resistor chip. make sure that is clean and in good condition. Try a spare key if you have one and see if that corrects it.

Good luck

BC

 

Hi There,
I would replace the fuel filter & then if there is no change.Pull the fuel line off & turn the engine over. You should have a strong steady stream of fuel coming out. Sounds like your electrical system is reliable as it starts every time.
robsc501

 

Thanks everyone we are on the move.

 

Sounds like CLB to me.

 

I am going to say that it is very unlikely that it is the fuel filter being that he would have a surging idle and it would not cruise very well or at all if it is clogged, but its never a bad idea to change it.

 

MEMMER

I goofed.. I toggle back and forth between C5 Tech and C6 Tech and lost my train of thought for a second. You DO NOT need to find a scanner to read your DTCs. You have one built into your car:

Here is how to use it. Read and post your DTCs:

READING YOUR Engine Diagnostic Trouble Codes (DTC)

This procedure should be carried out any time you experience a problem with your C5. Most inexpensive store bought aftermarket code readers will ONLY read power train DTC’s. Reading the DTC’s with the C5 built in code reader will allow you to read ALL the modules in the vehicle.

The Diagnostic Display Mode is entered with the following procedure:
1) Turn on the ignition but don't start the engine.
2) Press the RESET button to turn off any warning messages. (i.e. door open, trunk open ect)
3) Press and hold the OPTIONS button
4) While holding OPTIONS, press FUEL button four times within a 10 -second period.

Initially, the on-board diagnostics go into an Automatic Mode which will cycle through each module and shows diagnostic codes in a pre-set sequence: PCM - TCS - RTD - BCM - IPC - RADIO - HVAC - LDCM - RDCM - SCM - RFA. All codes will be displayed for each module. ( i.e. PCM = 4 codes) If none are present in a given module, you will see No More Codes on the display.

There are two types of diagnostic codes, Current and History designated with a letter suffix, “C” or “H”. A current code indicates a malfunction is present in the module displaying data. A history code indicates a problem existed sometime in the last 40 or 50 ignition cycles. When not accompanied by a current code of the same number, it's potential evidence of a previous problem, now resolved, that was not removed by clearing the codes. More likely it's an indication of an intermittent malfunction.

Intermittent codes are the most challenging of the diagnostics. An intermittent code may have happened once, may have happened more than once but is inconsistent or may be happening on a regular basis but not at the time the codes are displayed. History codes can also be caused by a current malfunction in a system that is not operating at the time codes are displayed. An example is the rear window defogger which doesn't operate until the Body Control Module detects engine rpm. For history codes set by a module that does not operate with the key on and engine off, a special diagnostic tool called a Scan Tester is necessary to properly diagnose the malfunction.

Once the system has displayed all modules, it goes into the manual mode which allows selection of each module using combinations of Driver Information Center buttons. Manual mode can also be entered during the automatic sequence by pressing any button except E/M. Once the display shows Manual Diagnostics, select a module by pressing the OPTIONS button to go forward or the TRIP button to go back. Once a module is selected, a code is displayed, and if more than one are present; press GAGES to go forward or FUEL to go back.
To exit the diagnostic mode at any time, press E/M. If you want to erase codes in a given module, press RESET To reset the codes once in manual mode, press and hold RESET until it displays NO CODES Press OPTIONS to go to the next module. Repeat the steps until you have reset the codes in all the computer modules.
NOTE!! Only reset the codes IF you want to - it is NOT necessary to do this. Clearing a code does not repair a problem. You are simply erasing the evidence of it in the module's memory. If you clear the code/s, and extinguish the Check Engine Light, your emissions status ready will NOT allow you to pass an emissions test until you have completed the required driving cycles. There are a few body module DTC’s that if set will prevent the module from operating properly. Once the DTC is cleared, the module will return to full function. This is not true for power train DTCs.

If you have never read and cleared your codes, there will probably be a lot of old history DTCs. It is recommended that you clear your codes and see if any come back during a driving cycle. Those are the ones that you need to concentrate on diagnosing.

Once you have the codes, the next question is: What to do with the information?
First, consult the factory service manual. Any serious C5 Do-It-Yourself owner should invest in the Corvette Service Manual of the appropriate model year. The Service Manual is really a requirement if you want to understand and work on your C5.

NOTE and a WARNING. You can read the DTCs while the engine is running. I pull mine up all the time while driving.
WARNING. Don’t become distracted while reading DTCs while your driving and cause an accident!!!!! Use common sense and drive safe.

These are some very good C5 Diagnostic Trouble Code (DTC) explanation web sites!!! They also explain how to read the DTCs

Here are some very good sites that explain what DTC mean:

http://www.gearchatter.com/viewtopic11755.php

http://www.obd-codes.com/trouble_cod...d-ii-codes.php

Make sure to include the H or C suffix when you post your DTCs!!



The C6 is NOT able to do this, The GM Engineers took it away, BASTARDS! So,,, sorry for that little bit od confusion.

Bill

 

bill
the information that i was looking for was not for my c5 but for a 91 gmc 5.7 pickup.because i am new here i didn't know that i should have posted in other cars.my apology.thank you anyway.