Ok well here it is guys. I just did a head gasket job on a 1997 neon. New timing belt, head gasket, waterpump, ect. Well I started it, it ran fine for about two days and 10+ starts, no problems. However, I was out doing the finishing touches on it a couple of days later and wile it was running, I reved it a few times and was going to shut it off when it just cut out. No noises or anything (does turn over fine). At first I thought the timing belt slipped off, But after an hour I had the engine mount off and could see that it was indeed on and timing marks were right. Then I did the thing I should have done in the first place and checked my spark. No spark. I was hoping it would be something simple, but so far nothing. I put a volts meter on my coil leads (not green/orange) and I am not getting anything into it. So I know that my coil, plugs, and wires are good. I replaced the cam pos. sensor, had the crank sensor checked (good) and I got a OBD II scanner for christmas and, guess what? It isnt throwing any codes!! Not a one. I have gone over every inch of wiring in the car, I know that it dosent have anything to do with the ASD relay because the fuel pump still works and the injectors are firing. I have narrowed it down to three things after studying the schematics: 1. PCM 2. microfarad capacitor (not sure what it does) 3. Pigtail to the coil (I dont think so but a possibility). Does anyone know exactly what the capacitor does? The other reason I think it is electrical and not mechanical like a wire is because it shut down wile it was running and it wasnt hot enough to melt anything and the way it cut out I think it was the PCM. Has anyone everhad any experiance with this?? Please help I am 14 and this was my first head gasket job on my sisters and recieved no help, my father lives in florida. Anyone with any info will be thank with much praise!!! THANKS

 

yes check the feed line from your pcm with your volt meter. the pcm for the 95 is fickle.i dont know the color youll have to check a skimattic

 

Also check the connetor that hooks to your coil pack some time it won't click all the way on when you put it back together and it will slip off just a slight bit and it won't get a good connection.. I also think its that because the viboration from the motor could of made it slip off..So if you want to check it it's the connector on the right side of the coil pack if ur standing in front of the car....see if thats you problem email me back.

 

Ok guys I Dont want to sound rude but if you read it I am NOT getting anything into the coil feeds so this is not my problem. Has anyone every heard of a PCM knocking out the ignition?

 

If you don't have 12v on the DK-GRN/ORG coil lead with the ignition in the run position then check fuse #21 and the auto shutdown relay as they would disable both the injectors and the coil.

If you still have no spark pick up a Haynes manual and see section chapter 5 section 6 for coil driver voltage checks.The common coil terminal DK-GRN/ORG is 12v when running and the DK-BLU/TAN and BLK/GRAY are connected directly to the computer and ground the terminals intermittently to produce spark. Caution: shorting these conductors could damage the computer.

Check the coil pack with an ohm meter the primary side should read 0.45 – 0.65 ohms from the center terminal to each side terminal. The secondary or high voltage side should read 7000 – 15800 ohms from output terminals 1 – 4 and 2 – 3.


Hope this is of some help.

 

Bythe way, the auto shutdown relay is not connected to the fuel pump it has a separate relay but is still powered by fuse #21.

 

I forgot about the Capacitor it is on the 12v supply line GRN/ORN as a noise suppressor, if it were shorted fuse #21 should blow and could possibly damage the asd relay. If it were open you would probably hear RF noise on the car radio.

 

Well guys I appreciate it but everything so far I already know... I do also have a haynes manual, I have checked the coil and such.. Keep them comming though!!

 

no dude, Im saying that the pcm somtimes loses its signal coming out if theres a small prob along the way it can fri the pcm on that signal line. if the signal from the pcm is dead than changing it is your only option. after you may want to find out why it bleeted your signal before it fries another. this is one of the rare cases i would suggest a dealer shop.

 

Sounds like you have done all the appropriate tests. Assuming the blu/tan and blk/gry leads at the coil are not providing the proper ground signal to the coil, then the only thing left seems to be the pcm or the wiring and/or connectors between the coil and pcm. It does seem unlikely that the wiring to both coil leads would go bad at the same time. Double check any connectors you had a disconnected to make sure there properly seated.
Beyond this I’m not sure what to tell you. You could try to reset the pcm, it’s worth a try.

Sorry I couldn’t be of more help.