CarbonRevo

Well, I have been having this little problem ever since I replaced my broken valve spring. Generally, what happens is the car is driven, it gets very hot (radiating heat from the engine bay), then if it's turned off and you try to restart it about 10-20 mins later, it won't start. Generally, it starts fine if the car is cold, or it has sat for roughly an hour and cooled down enough.

I searched on this issue, and came up with replacing the DME relay and the DME temp sender. My temp sender was very nasty and had "insulation" on it, causing it to not read properly (what my mom told me). Well, it seemed as if that fixed the problem. I drove the car numerous times yesterday around town (but still worried it wouldn't start if shut off). I went to a friends house to help lower a WRX, and the car sat for roughly 2 hours. It fired up fine. I brought it home, sat outside and checked it to restart after 10-15-20 minute intervals, and it did every time. My dad then wanted to go for a cruise in his Chevelle, so I said I would follow along in the car. Car ran great the whole time (probably an hour trip). My parents then told me to meet them to eat, which I did. I turned the car off, and we were inside for around an hour. I come out, it starts up fine. I go home to do some duties after eating some nasty food (which took me a good 10-15 minutes). I come out, and the car is all cranks. Wouldn't start. Fortunately my dad parked his truck in front of my garage stall so I couldn't push the car inside. I had to leave it sit outside all night as I was furious and my dad was laughing at me. So I left. I come back 2 hours later, and it's still all cranks, but would catch and run like COMPLETE crap. Rough idle, CEL is on, and MAYBE 2-300rpm idle. If you gave it gas, it would instantly die. I went to bed.

I get up this morning, look outside, and the car isn't out there and my dads truck is gone. My parents pushed it in for me I guess as he said it wouldn't start. I go out, I crank the car for about 5 seconds, and nothing. Try again, and it fires right up. I let it idle for a while, checking the motor over for no problems/leaks or anything. Back it out to realign it into the garage. Pull it in, shut it off and attempt to restart it 4 times. Each time it would start faster then I have noticed any other 944 start. For the first second-second and a half, the tach would NOT bounce. As soon as the tach would bounce, the car would fire up. I have had this all along, but always suspected since it bounced at the end right before it would start up, that my reference sensor is fine.

I didn't drive the car any, as I'm afraid I will get clumsy and stall it somewhere (my luck), and it won't be able to re-start.

Any ideas? I tryed to be thorough in my post (sorry for length) with what it's been doing, but please ask questions if I didn't post something relevant to this problem.

Thanks!

Dal Heger

Replace the ignition module (driver's side below the headlight, attached to the fender).

CarbonRevo

What aspects of the ignition does this module operate? Would it cause the car to be hard to start/ not start when it's hot? The car started fine when cold every time before last night. Last night was the only time it wouldn't start when it was cold.

::edit::

I went out and decided to mess with the ICM. I first started the car, perfectly fine. About 2 seconds and it fired. I then took the ICM all the way off the fender and disconnected it. Went and try to crank the car and it had the EXACT same cranking as it did last night when I got in and tryed to start it about 15 minutes after I got home. The tach takes a second or so to start bouncing, but I assume this is just the time it takes the ref. sensor to pick up and send the signal to the DME and to the tach and what not. Car slowly builds oil pressure to 4-4.5 bar when cranking, and cranks the exact same way it does when the car is hot and won't start (when I unplug the ICM). Wether or not this is it, it sure does seem like this could be it. I'm not calling to any fuel problems. All injectors fire the same speed and loudness when I stethoscope them when car is running. Car also runs fine when I accellerate hard and doesn't sputter/hesitate like a bad fuel pump or low fuel pressure might indicate.

I really need to go drive the car and get it nice and hot, bring it home and wait until it won't start, THEN un-plug the ICM and see if the cranking changes, and re-connect it to see if it fires back up. If it doesn't, I think we have the culprit (or so I hope).

bjzorn

Cory,

I am having the same problem on my S2 as well. I did a fuel Pressure check and fuel pressure is fine, so I know the fuel pump is good, I let the car idle for 45 mintues on Saturday when I was moving into my new place and it idled and ran great when I took it out for the first time in 2 weeks. I drove it a little hard as well. got back home shut it off and tried to start it again and it fired up for a couple of seconds then died and wouldn't start again. So I believe it is the ICM.

here is the part number to make it easy for your parts guys over at Aristocrat. 928-602-706-01