I had a thread about this a while ago, but now that I have more info on the problem, I decided to start a new thread.



So last fall my car decided to not start anymore when it was hot. (Car still starts perfect when cold) Itwas a slow progression over about 2 weeks here and there, and then nothing at all, refused to start hot. My first inclination was that it was my CAS going bad, which it sorta turned out to be.



Anyways, when my engine bay was completely cold, I ohm tested my current CAS and another one from an 88 S4. Both speced out fine. I also ohmed out my coils. Also good. Start the car up, pops off fine as usual, and I let the car warm up until my efan comes on. Turn the car off and try to start again. Nothing. ((MY efan was going without the car running and draining juice from the battery, so I unplugged it and tryed starting without it on, still nothing)) So then I took the other CAS I had and popped that into the hot engine. Car started just fine, like it was cold. Amazing. So i let that CAS warm up with the engine running, shut the car off and try to start. Nada. And to be sure I stuck my first CAS into the fridge for about 5 minutes to cool off and put back into hot engine, and again my car started.



So what I've boiled it down too is that when my CAS is hot, car no starty. ALso, I ran my car for a year with my current set up with no such problems, AND i can push start it when it is hot and it will start.



So if anyone has any ideas or has had a similiar problem, please let me, cuz I really want to figure this pesky problem out so I can drive my car this summer. Are there any other sensors that can be affected by heat? Any wild ideas will do, I just need some ideas on where else to look for this pesky problem.



Matt

any codes?

The car has a Haltech E6X, no codes.

i would like to tell you to send your box into haltech and have it fixed, but your experiment with your cas in your fridge... which is hilarious.... seems to throw a definate red flag.... maybe the box is just too sensitive to the small increase of resistance when the wires get warm. maybe that's what the 'fix' is that we keep hearing about...?

Yeah, me and Brandon were talking about it today, and he said the same thing, that maybe I need to insulate my wires better for my CAS and maybe insulate the Haltech better from the firewall. I wonder how hot it actually gets down there, I mean the turbo and dp are right there.

i really don't think 'insulating' your wires is going to keep them from getting warm. the real problem is the box i think. did you call haltech yet?

New findings tonight....



Took a spark plug out after car had warmed up suffieciently. Set it on my radiator so it had a decent gound. Cranked over the engine and my dad said that it was sparking intermittently. Then to rule out another thing I took the brand new battery out of our boat and dropped it in, car cranked way faster, and it was getting decent spark, and the tach was bouncing???? https://www.nopistons.com/forums/pub...1047683561.gif This is opposite to everything I had determined in the last few days. So i plugged everythying back inot place and cranked engine over. NO SPARK AND NO START....



So what I am thinking is a possible solution, someone suggested on the haltech boards is maybe it is my engine grounds. Because that is the only logical reason I can think right now is that the increased heat is increasing the resistance in my engine grounds and not allowing the spark to go off. I have one big main ground and one littler one for each rotor housing. Going to try hooking up a few more gorunds tomorrow and maybe increase the size of my rotor housing grounds. I may also need a new battery, been a while since that one has been tested and it doesnt hold a charge very well. probly junk.

check for a parasitic drain on the battery as well.. well i guess it wouldn't matter if you flip your breaker everytime. still good to know if there is an amp draw when there shouldn't be though...