95 LT1 ignition issue
Thread Starter
Teching In
Joined: May 2010
Posts: 21
Likes: 0
From: Crystal River FL
95 LT1 ignition issue 95 Z28 A4 starts and runs perfectly cold. Once it reaches temp shuts down. Next crank stumbles, then no-start until cool again. There is no spark from the coil during no-start. Car has less than 5k on rebuild. New optispark and Opti harness, new ICM, plugs, wires, stock coil is spaced. No codes as of now. Redundant grounds. Any ideas? I'm lost. PCM and coil are the only components in the system that haven't been swapped. My old Opti harness was in bad shape, not sure if terminals touching could have damaged my Opti or my PCM? I'm stuck bad and I'd appreciate any input. Thanks.
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The ICM is an electronics package and has a operating temperature range, this is why it has a heat sink to cool it.
Swap it with another one and see if the issue stays or goes.
Why did you install this ICM from Autozone? Was the old one bad?
Swap it with another one and see if the issue stays or goes.
Why did you install this ICM from Autozone? Was the old one bad?
Last edited by Paul Bell; Jun 4, 2011 at 07:12 AM.
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Staging Lane
Joined: Dec 2010
Posts: 63
Likes: 0
From: delaware
the cardone optis from auto zone r junk i had 1 barely last 1000 miles about 3 months. if its not your problem it will be sooner or later.
the optis can cause the same symtoms when goin out. http://shbox.com/1/4th_gen_tech2.html#opti_test. try shoeboxs page theres alot of good testing procedures.
the optis can cause the same symtoms when goin out. http://shbox.com/1/4th_gen_tech2.html#opti_test. try shoeboxs page theres alot of good testing procedures.
Staging Lane
Joined: Dec 2010
Posts: 63
Likes: 0
From: delaware
the best way i found to test is to either unplug the fuel inj. or pull fuse , then pull icm plug and test white wire (b i believe) while cranking. it should read like 1-4 volts ac if u get that then its getting signal from pcm and opti. http://shbox.com/1/95_ign_system_schematic.jpg
Last edited by KAMSVT; Jun 3, 2011 at 11:33 PM. Reason: adding
Thread Starter
Teching In
Joined: May 2010
Posts: 21
Likes: 0
From: Crystal River FL
Thanks for all the good input. Ill run a test in the morning cold and then hot. We pinpointed the icm in another thread and that's why I replaced it. I even mounted it to a CPU aluminum heatsink with a cooling fan. I imagine its overkill but it can't hurt...
Teching In
Joined: Jun 2011
Posts: 2
Likes: 0
i think you could plug in old opti harness and opti. turn ignition key on and hand spin opti looking for spark. if i was to guess sounds like coil have seen them go bad a lot and they usually fail hot. you could also run car till it shuts down then spray bottle with water and spray down down coil . carefull not to get opti wet.
Staging Lane
Joined: Dec 2010
Posts: 63
Likes: 0
From: delaware
I JUST READ YOUR OTHER THREAD. dont see were you confirmed anythingto say its def icm.
have you scanned for codes?
have you tested to make sure your getting power to the icm when the problem accurs? (via aformentioned procedures.)
not tring to be a dick tracy but need more info like test results and details!
have you scanned for codes?
have you tested to make sure your getting power to the icm when the problem accurs? (via aformentioned procedures.)
not tring to be a dick tracy but need more info like test results and details!
