As posted before I am having issues with car dieing at wot. Thinking it was the fuel pump I checked the pressure today. Start up it read 35lbs. On the road 42lbs. When I goosed it to see if pressure would jump and car backfired and died. Pressure held at 42lbs. Wouldn't restart. It has done this before but would always restart. The opti is new (ac delco) plugs, wires are new also. Its not throwing any code. Was thinking maybe icm or coil. Any suggestions appreciated as the car sits useless atm.

 

Coil test http://shbox.com/1/coil_testing.jpg
Have not found an ICM test yet but maybe I am missing it. Here is shbox http://shbox.com/1/4th_gen_tech1.html

 

Was going to replace the coil and icm anyways sooner or later so guess I will do it sooner lol. Just wondering of this sounds like an issue with either of those

 

When it does it you can also check the opti for signal. Just to make sure the ICM and coil are getting what they need. It is on that site I link as well. Typicaly coils will start to miss or stop fireing when they get hot. same with ICM. If you have not done the mod to get the ICM off the head now would be a good time as well. Very simple to do and the instructions are on that site as well. I am battling random missing right now and it only will do it when the engine has been running for a bit and the under the hood temps go up. I need to do the coil test as well but I have been fixing other problems lol. I just hope it's not my opti either. lol How many miles are on the ICM and coil?

 

Well they are they stock ones with 122k miles on it. I had planned on doing the mod too figures might as well

 

So how about all 4 plugs on the drivers side had backed almost completely out. Maybe I didnt tighten them enough?? Could this have caused the missfire and die at high RPM? what about not starting back?

 

HUH................yES.........? OPEN CYLINDERS DONT COMPRESS.......

 

yup. Here is what happens with that. I did this once as well. The spark plug hole is tapered into where the threads start. The plug sockets you use to install them like to hold the plug deep in the socket. So, when you start to tighten them the plug socket bottoms out on the tapered edge of the head and you think you have it tight when in fact they are only about 5 to 10 ft lbs tight. I now always tighten them and then take the socket off and put it on back on but just so it has room in-between the head and the socket. then I tighten it some more.

 

Well aware open cylinders don't compress. Try not to be an *** about it. The plugs aren't out I said they had backed out some. It ran pretty good until high rpms. I checked spark last night and not getting any so replacing coil and icm today

 

Post back and let me know if that fixes it. I need to look into doing the same so I can clear up my miss.

 

144 dollars later new coil and icm she fired right up. So far running the best since I have bought it

 

ahh I got do that then mine have 100k and they are 14 years old now. Post back if it acts up. I have to find some cash which isn't gonna be possible with my wife and little girls birthdays this week and next + my mothers today and my sisters a week ago. lol September sucks for my wallet.

 

I've been almost the same trouble with my 93 T/A let me know it works out for you. Mine runs great but after it's been running for a while when you shut it off and let it set for about 15 minutes it wont start again until it's cooled off completely, but if you try to start it right after you shut it down it does start, I'm almost convinced it's my icm I've already replaced the distributor and coil so I hope that the icm is the last of it. The distributor was bad and so was the coil. Again please if you can let me know. Thanks

 

Drove it about 100 miles and all is well. Looks like that was my issue. Hopefully she'll stay running for awhile now lol. Mine was more expensive than normal because I opted for lifetime warranty. The cheaper icm was 70 I think

 

hmm having same issues, fires up, runs a couple minutes, shuts off wont restart for almost an hour or more, cold runs, warms up a bit and shuts off. spark there, kinda weak, 40lbs of fuel pressure, which is pretty good considering it has 184k on it and i doesnt look like the tanks ever been down. ill try next week and see, thanks to those who posted the tech links. ill be keeping an eye in here for info. sorry for highkacked thread.

 

It's on topic so not really a thread jack since we are all talking about the same thing.