1994 Corvette
Melting Slicks
Joined: May 2014
Posts: 2,888
Likes: 590
From: New Port Richey FL
If you have already thrown in all the expensive Parts it is time as suggested go back to the basics, Fuses, Flow Charts in the FSM.
(a new Opti Doesn't always mean a good one)
One thing I had happen to me I installed a new Opti and the car started ran smooth Topped off Coolant. and started to do a little wire clean up and put Air cleaner Tube back.
While putting the Wire Loom back around the ICM & Coil Wires car cut off NO SPARK wiggled ICM&Coil wires while cranking car started, found one coil lead Questionable and same with 1 or 2 wires on the ICM replaced the pigtails for ICM & Coil all is well now a year.
(a new Opti Doesn't always mean a good one)
One thing I had happen to me I installed a new Opti and the car started ran smooth Topped off Coolant. and started to do a little wire clean up and put Air cleaner Tube back.
While putting the Wire Loom back around the ICM & Coil Wires car cut off NO SPARK wiggled ICM&Coil wires while cranking car started, found one coil lead Questionable and same with 1 or 2 wires on the ICM replaced the pigtails for ICM & Coil all is well now a year.
Last edited by s carter; Nov 9, 2017 at 03:34 PM.
Melting Slicks
Joined: Jul 2005
Posts: 2,649
Likes: 863
I agree with the other posters - You need to go back to basics, and check to see if you have power - do you have a signal to the injectors, do you have a check engine light on, do you have a spark at the coil output ???
If you do a search on this part of the forum - I've previously posted instruction on how to determine if the opti is doing what it's supposed to - basically you get the 4 wire connector that is clipped to the pass side of the intake, and backprobe the 4 wires while having someone crank the engine over. One wire is V+, one is ground, one is the hi-res output from the opti - the other is the low res output. If you have a DVM, and you have power and ground - you set the DVM to measure frequency and see if you are getting anything on the low res or high res while cranking.....
If you do a search on this part of the forum - I've previously posted instruction on how to determine if the opti is doing what it's supposed to - basically you get the 4 wire connector that is clipped to the pass side of the intake, and backprobe the 4 wires while having someone crank the engine over. One wire is V+, one is ground, one is the hi-res output from the opti - the other is the low res output. If you have a DVM, and you have power and ground - you set the DVM to measure frequency and see if you are getting anything on the low res or high res while cranking.....
Le Mans Master
Joined: Jan 2006
Posts: 5,620
Likes: 206
From: Orlando FL
What was the original problem?
Was the engine running before you replaced all these items?
Need to check for 12 volts on the coil where it should be.
Need to check for the PCM output to the ICM. Should be 1-4 VAC while being cranked. It's the white wire, terminal "B" of the ICM. If there is no drive, then there is no spark. If there is drive, then possible ICM problem.
If you don’t know how to make these tests, ask for specific directions.
Was the engine running before you replaced all these items?
Need to check for 12 volts on the coil where it should be.
Need to check for the PCM output to the ICM. Should be 1-4 VAC while being cranked. It's the white wire, terminal "B" of the ICM. If there is no drive, then there is no spark. If there is drive, then possible ICM problem.
If you don’t know how to make these tests, ask for specific directions.
