95 impala stalls while driving

[95-Pala-SS]

hi i have a 95 impala it has a new msd opti maybe 5k miles on it, new icm , new coil, new oem temp senor ,new acdelco fuel pump,pcm for less ecu . the car shuts down while im driving randomly. and doesnt start right away i have to let it sit for 3-4 minutes and it starts up like nothing was wrong . if any 1 has any suggestions i will be happy to hear anything im ready to pull my hair out . the oil level light pops up but i have it bypassed with a paper clip but the light still pops up

[cletus284]

Did you check the Opti vent harness? Also, the MSD Opti's don't have the reputation the AC Delco does. I've seen a few bad ones on here over the years.

[DiGGM95]

Originally Posted by 95-Pala-SS

hi i have a 95 impala it has a new msd opti maybe 5k miles on it, new icm , new coil, new oem temp senor ,new acdelco fuel pump,pcm for less ecu . the car shuts down while im driving randomly. and doesnt start right away i have to let it sit for 3-4 minutes and it starts up like nothing was wrong . if any 1 has any suggestions i will be happy to hear anything im ready to pull my hair out . the oil level light pops up but i have it bypassed with a paper clip but the light still pops up

I noticed that you also have seen the oil level light flash once very quickly as the car decides to take a crap and die out.

I have simply cut and spliced the oil level sending unit wires and mine still did that.

I believe its the key-on engine-off light test, I originally thought it had something to do with the opti losing the low-resolution signal, but if you think about it, how often do you ever have the engine die out with the key left on in these cars? It seems abnormal, but where you rarely have this scenario happen, it just looks odd to see the warning lights come on like that.

[infomanSS]

When the ICM was replaced, was thermal grease/paste applied to the backside before installing? It sounds like the ICM is overheating, so the ignition is killed, then after it cools off the car will start.

[Narc 9c1]

Sorry to revive this thread but my car is having a very similar problem. I have been blaming the fuel pump but decided to change the pcm and the problem went away...for a few days. Now it's back and I've got no codes to check.

Did you solve this issue?

[Henry '06]

Vets can chim in if Im wrong but once it dies again try to narrow down what it might be. I doubt its fuel related becuase when the fp is dead its dead.

Try this once it dies with out warning, remove the plug from the opti thats connected to the coil. So its should be connected to the coil. Have it dangle next to something metal, the Water pump should work. Attempt to crank you should hear sparking.

If it checks out good, plug back to the opti, now remove a wire from a sparkplug let it dangle close to something metal listen for spark. If no spark you have an Opti issue more than likely.

If you didnt get spark at the coilwire connection it could be either the coil or ICM.

Good luck.

Also doesnt hurt to check all elec connections related to ICM Coil and Opti.

[Narc 9c1]

Thanks. I will try those techniques.

Just to clarify, the car dies intermittently while driving after it's been warmed up (no amount of throttle can even attempt to keep it alive). It does not restart right away and usually takes a few minutes before it does. A lot of threads have pointed to the ICM overheating. My fuel pressure reads fine during this time but when trying to restart, I do not hear the fuel pump prime. After a few minutes I will hear the prime of the fp and it starts just fine.

If it weren't for that stupid fuel pump not priming, I would feel more confident about spending the $175 on a new ICM.

[infomanSS]

ACDelco ICM at Summit Racing is a little lower...may be lower at another place as well. Summit will price match.

http://www.summitracing.com/parts/acf-d1986a

[Chris96Coprice]

ICM typically dont go bad that often....never changed one on my 96 9c1 and it had over 250k on the clock...100k I put on myself....Now I will tell you that this sounds like a electrical fuel issue however. I had the same problem in a 96 ss I had at one time and the guy before me spend hundreds and hundreds of dollars trying to solve this issue 4 optis, fuel pump, ECMs, Plugs/wires. Turns out it was the fuel pump harness inside the tank. The wires will get "burnt" after a while and cause similar issues. Sometimes its good then other times it makes bad connections cause some of the connectors are corroded and wires are a little loose/burnt.

Not saying this is the problem, and its a PITA to drop the tank, but it is a fairly common problem....once I swapped em the car never ran so good in its life.

[Narc 9c1]

Thanks, I'm trying to avoid dropping the tank as I just installed a Racetronix Pump in August of 2012