Guys help me out here. My car has been driving normal for a while and all of a sudden today i'm driving, i make a right turn and the car dies while driving. I pull it over to the median. So i check the back and nothing is loose. I am about to give up and call AAA but i go to back and push in the spark plugs, and the three connectors on the coil, none of them were loose to begin with i just want to make a better connection, and it started for me and i was able to drive it back to work. But i put it in park when i got to the parking lot and when the idle went below 1 it died. Whats going on here? Can someone chime in and help me here? Thanks you guys.
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02:52 PM
PFF
System Bot
TXGOOD Member
Posts: 5410 From: Austin, Texas Registered: Feb 2006
You are describing the symptoms of a bad ICM....so look for the tach to move when you crank it. This tells you that the primary ignition signal is getting to the computer. If the tach needle just sits there, The ICM or connectors are probably bad.
Well i just went to go crank it now and it started right up and didnt die for about 2-3 minutes. But, when i was cranking it before the tach didn't move. So i'll check the ICM but why would the car start now without any issues?
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03:43 PM
Formula Owner Member
Posts: 1053 From: Madison, AL Registered: May 2001
Remove the ICM and take it to a major parts store, they can test it on a machine. If bad then replace but look for evidence of what caused failure. Moisture in area, heat (dirt underneath sink area), poor terminal connections kill them. If good suspect pickup coil. Might as well do cap and rotor while you are in there is they are older than 2 years. Good luck.
I have had good luck with delco ICMs and bad luck with car parts store brands. One ICM I bought lasted 3 days....with a lifetime guarantee....which means you could do it all again in 3 more days....
I was able to drive it from work to Autozone to pick up a new ICM and then from Autozone to my neighberhood. But once i got into my neighborhood it died. I replaced the ICM but nothing happened. The tach wasn't even moving. So i unplugged the wire on top of the distributor that connects to the coil to check for a spark, and no spark. So i went back to Autozone since i have that part on lifetime warranty and bam the car started right up. My question to all of you is why would the car work again and then die again? And why did the ICM AND ignition coil both go out? I checked the ICM at Autozone and it didn't pass. Thanks you guys!
Several possibilities. ICM are designed to work with a specific coil of specific resistance, inductance and voltage ranges. You said the coil was already replaced and aftermarket coils tend to not be as good as OEM coils. I have seen several cases where "high performance coils" fry ICMs and have experienced this myself. MSD coils killed a BWD ICM in about 30 seconds. So your coil could have fried the ICM, especially if it went bad (high internal resistance, fluctuating voltages, etc). Coils go bad from excessive heat and corrosion so check to see if your coil blower is still working in the trunk compartment. I'm sure you cleaned the coil mounting surfaces when you installed it for a good ground.
Resistance changes as a function of material temperature. When your car heated up it most likely changed the electrical signal enough to be out of operating range of some ignition system component. When it cooled back down you could drive it for a while. This over-heating or out-of-range operation of electronics will kill them very quickly. Cars are designed as "systems" and changing one part of the system can have dramatic effects on the rest. This is probably the cause of your problems.
It's good to see your inquisition as to the root cause of the issue. It will keep you from experiencing the problem again. To summarize: use quality OEM ignition parts whenever possible (usually Delco), keep clean, tight grounds and connections (use dielectric grease), make sure coil cooler is working. Hope this helps.
