Finally got my car running right and all of a sudden it randomly shuts off.

What can cause random shutoffs?

I drove the 100 miles yesterday AM to the strip and two miles before I got there the engine just shut down. I pulled over, opened the hood, and couldn't see anything unusual. Itried to re-start the car and is sounded like the battery was dead. I waited five minutes and it fired right up like nothing was wrong.

I made it the next two miles to the track without incident. I went through four time trials and three rounds of eliminations before it just shut off again, this time while making the turn onto the return road. After a could of attemopts to re-start what sounded like a dead battery, it started right up like nothing was wrong. I then made it to the final round when I redlight with a .497 light (ouch), and when I made it back to my pit it stalled whaile backing into my spot. Same story... A couple of nothings or a half hearted turnover and then it fired right up.

I packed up and left and on the way out the track gate it died again. Same story. I then proceeded to drive the 100 miles home without incident.

This morning I got in it to drive to work and the car just turned over and did not want to catch. Finally it did and I made it the eight miles to work without incident.

History:

Three opti's this year. Two ignition control modules this year. Fuel pump is one year old and has had to be replaced every year for the past three years. New fuel pump relay, that too goes every season like clockwork. New transmission internals three weeks ago and new torque converter. Re-adjustment of lifters last week (picked the car up from dealer on Friday). MSD 6A box is bypassed and has been for the entire season thusfar. MSD blaster coil is one year old. New spark plugs. New plug wires.

 

heat sensitivity normally would point to the coil and/or ICM. I have heard of the PCM also being affected this way by heat though. If you know a way to test the ICM thats where I would start (and let me know what it is!!) its known to be heat sensitive.

My only issue with that is you said it restarts hard, like its a dying battery? If you mean it revs real slow and doesn't ever kick in, that doesn't sound like an ignition problem to me - more like a lose/broken/corroded connection at the battery and/or alternator. Might want to give those a nice cleaning too...

 

Yea, immediately after dying it barely cranks at all. Then it just fires right up like nothing is wrong. I thought it might be a bad ground at first so I put on a new ground strap from the block to the engine bay, a ground wire going from the block to the battery, and a ground from the battery to a post on the fenderwell. All are clean and tight. ICM has been replaced twice this year. I am wondering if the shifter could be causing the problem because the transmission has just been re-done and my car is set up only start in neutral (not even park). What if the neutral safety switch is messed up. Couldthat cause this type of scenario?

 

Sounds like the ignition module to me.

 

No codes?

 

I would have to say the ignition switch under the steering column. My old Z did the same thing, almost rearended a car once because the brakes stopped working effectively. It would randomly just die going down the road. Shoebox has a link that shows how to fix this problem. What happens is over time the connector ends melt from constant heat over the years, which results in poor connection. Took me less than an hour to fix...Good Luck

 

I suspect it's in the wiring.

I used to have problems almost every time I started my car, sometimes there would be nothing there at all, like there was no battery in the car- although the acc position would still work
So I replaced my ignition switch and that seemed to help out, it's been several months now.
Then yesterday it was raining out, really hot and humid, so I had the AC blasting, lights on, radio up, parked and went into the store, 5 minutes later I came out and nothing. I had to sit there for about 5 minutes before I got a response from the car, and then of course it starts up like nothing at all. So it could be a burnt wire somewhere, or bad connectors, or the switch itself. For me, it seems to be that and a combination of low voltage from the battery. During the winter my voltage gauge shows around 3/4 at startup to over half when it's fully warmed up, now it just sits around half all the time and will go below that with ac and lights on, especially at idle.

I guess I'll just have to clean up all the connections I can find and hope for the best. I really don't want to have to go dig that switch out again. That one cable in the back is a b!tch.

These cars just can't stand heat. Can't wait to go back up north soon.

 

I have been cleaning and re-seating every connector I can find. This appears to be more or a process than an event.