My iroc refuses to start. It cranks over and over and stumbles, but never fires. It's an 87 IROC, 350 tpi car. Here's what i know so far:

1.I have fuel. I have ample fuel pressure at the rails and the injectors have voltage.

2.I have spark. I have a nice spark at the coil and at the wires as well.

3.The ecm seems to be functioning. I'm getting code 12, and that's it. I have a battery disconnect, so any other codes were wiped out. And i dunno when it would trip codes again. I'm assuming the car would have to run first and i can't get it to start. Cranking for a period of time without starting does not set any codes.

4.Some background. The car has predominantly sat all winter, and a good portion of fall as well. About a month ago, I jumped it, let it run for a significant amount of time and drove it across my parking lot. It wasn't started again for a few weeks because the battery would not hold a charge. I swapped out the battery last weekend and the car started right up, but ran extremely poorly. i couldn't even move it across the parking lot without stalling several times. It was hunting for idle and it was running very rich, but the ecm had 0 power at all for a few weeks, so i assumed at the time that it was just trying to "re-learn".

I disconnected the battery after i moved it and it sat again until today, and it refuses to start.

Any suggestions?

A few of my thoughts are:
Bad gas - could it really be so bad as to not even let the car fire? The gas in the car is not "that" old. Some of the gas in the car may be as old as august, but i did top it off again at least one time since.

Fouled plugs - the car has a lot of mileage and is burning some oil, not to mention it typically runs very rich. The plugs are pretty recent, but do you think they could all be so fouled as to keep the car from running???

any other suggestions? something i'm overlooking maybe?
seems like i have all the required parts of combustion, namely air, fuel,and spark

 

i'd check FP with a gauge and the spark with a spark checker. did you check the cold start injecter? like you said air/fuel mixture, spark and compression is all you need.

 

FP was checked with a gauge. I have 50lbs at the rails, which is normal (supercharged car)

i didn't check the spark with a spark checker, but it seems plenty hot enough to fire. I hooked up one of the wires to a spare plug i had sitting around, and it fired it very nicely.

 

try replacing the plugs or check to see if the timing has jumped.

 

FWIW, even though you may appear to have good spark, a weak coil can cause the problems you are having. It seems more noticable with aftermarket coils. I had the same problem long time ago with an Accel coil...replaced the coil with another Accel and it was good to go. A Mustang friend of mine had the same no start condition as you. Even though he had spark to all cylinders, his MSD coil was weak. We put in another coil and it's been fine ever since.

 

i do have an msd coil that's a few years old. that's worth further exploration definitely. thanks for the idea.

 

take a look at the ignition module. i had an experience once where my GTA would start for a while then just die or just wouldn't start at all. i checked the spark with a spark checker that went between the plug and the wire boot and i had weak/no spark. i hope this bit of advise helps.

GTAman

 

take a look at the ignition module. i had an experience once where my GTA would start for a while then just die or just wouldn't start at all. i checked the spark with a spark checker that went between the plug and the wire boot and i had weak/no spark. i hope this bit of advise helps.

GTAman