stalling problem

[bollars]

I need serious help as I'm about ready to give up on this car. It starts up and runs fine for about 5 min. until it warms up and then starts to stall, I can't keep it running. About 5 months ago it was doing this so I replaced the coil with a cheapo and it ran fine until about 3 wks ago. Replaced coil again and it ran for 2 wks. with no probs. Bought an AC delco to replace cheapo but no luck. Have had the opti replaced about 2 yrs. ago, doesn't seem to be the same symptoms. Any help would be appreciated.

[Joe 1320]

In order to provide decent tech advice, we need to know the model, the year, the engine, etc......

[bollars]

sorry. 94 LT1 M6. borla cat back and headers. PC reprogrammed and emissions stuff was deleted.

[Joe 1320]

There could be several things to check......

1. Coil drive module. It sits right with the coil and is mounted on the front of the driver's side head. If it heats up and has issues, it will cut off the spark and the car dies.

2. Fuel pump giving out. As soon as it heats up, the flow of fuel slows way down and the car stalls.

3. Faulty coil

Scanning the car would be helpful..... ya need to find out what is going away, fuel or spark.

[bollars]

I think its' the spark, because when it starts to stall I can smell the fuel. Returned the cheapo coil because I thought it was faulty. That didn't work so then replaced cheapo with A/C delco and still no luck. So you think it could be ignition control module?

[Joe 1320]

I think its' the spark, because when it starts to stall I can smell the fuel. Returned the cheapo coil because I thought it was faulty. That didn't work so then replaced cheapo with A/C delco and still no luck. So you think it could be ignition control module?

Can't say for sure, but when my driver module went bad it exhibited the same problems that you encountered. The car would start when physically cool just fine. As soon as the driver module heated up from the engine heat and use, the car would stall. You can have the driver module tested free at many auto parts stores, the only problem is that they don't heat up the coil so a thermal failure cannot be detected.

[bollars]

yeah, I had it tested at autozone and they said it was within specs. I asked them about the thermal failure and he said that they ran it a couple times to check for this so I'm not really sure. I'm kinda thinking this is the problem also but don't want to spend money on it if it's not. You had the same problem? It will start up again and run for a little after it has cooled down again.

[97LT1Z28]

I had the same symtoms and it would also stall while driving at highway speeds. Mine turned out to be the pcm. Replaced it and it was perfect!

[Joe 1320]

If the car won't start and while it is acting up perform this diagnostic

http://www.f-body.com/forum/showpost...4&postcount=17

there's also another post that does something similar

http://www.f-body.com/forum/showpost...1&postcount=18

[Injuneer]

Sounds like it may start running excessively rich after it warms up. Two additional possbilities:

-coolant temp sensor problems. If the sensor is telling the PCM the engine is cold, when it isn't, it will start fine cold, then run excessively rich as the engine warms up.

-faulty O2 sensors, or some other problem that is causing the PCM to sense a "false" lean condition, and pour in extra fuel. Only becomes a problem when the PCM goes into closed loop, and starts using both the long term and short term fuel corrections.

[bollars]

If it's not throwing any code will a dealer be able to hook it up to computer to find the problem. I don't want to take it to a dealer then end up getting ripped off for like six hours of labor or something.

[Injuneer]

You need to get it scanned for codes. They shouldn't charge you more than 1 hour of labor for that. If they can't find any codes, they will probably be just about as lost as you feel at this point. They will, however be able to look at the operating parameters of the engine with their Tech scan tool, and may be able to pick up on issues like incorrect coolant temp indications, incorrect O2 sensor readings, excessive long term fuel corrections, etc.

If you tell them you only want a diagnostic scan, they should be able to give you an estimate for doing ONLY that, and you can decide if you wnat to pay the price.

A scanning software package makes a lot of sense. You can get FreeScan or DataMaster software for free, load it on a laptop, get the correct interface cable from AKM electronics, and it will cost you about the same as taking it to a dealer for a scan.

There are several of us here who can review your scan file for problems.