LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Car wont start, see what you guys think of this.

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Old Mar 26, 2010 | 05:35 PM
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Default Car wont start, see what you guys think of this.

Like the title states, my 93' just wont start. It turns over but nothing after that.

Just replaced, Opti, and plugs. Switched out coils and still nothing. Fuel pump was replaced with a Walbro about a month and half ago, that holds 40psi primed so I have fuel pressure.


Ran DTC codes and got a code 12 which is...DTC - 12 No distributor reference pulse (diagnostic test active)
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Old Mar 26, 2010 | 06:34 PM
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What I see from looking that up,
Code 12 simply tells you the ECM is not receiving any pulses from the distributor
Everything plugged in for optispark? Has the opti ever worked or this brand new?
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Old Mar 26, 2010 | 06:37 PM
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Originally Posted by chavez885
What I see from looking that up,

Everything plugged in for optispark? Has the opti ever worked or this brand new?
Yes its all hooked up.
It was working, then stopped, Opti was covered under warranty so i had it sent out and received a new one, and it still wont start.
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Old Mar 26, 2010 | 06:58 PM
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Have you checked the opti harness?
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Old Mar 26, 2010 | 07:03 PM
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Originally Posted by bigj2717
Have you checked the opti harness?
Yes I took it and inspected each wire, nothing wrong with it.
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Old Mar 26, 2010 | 07:18 PM
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Could it be the ICM? when mine went out in my ta it wouldn't start either. just kept cranking. Pull your coil wire off your opti, and barely hold it to the post and if there's no spark then it could be the icm. just thought I would throw it out there.
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Old Mar 26, 2010 | 07:43 PM
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Originally Posted by 06blackGTO
Could it be the ICM? when mine went out in my ta it wouldn't start either. just kept cranking. Pull your coil wire off your opti, and barely hold it to the post and if there's no spark then it could be the icm. just thought I would throw it out there.
Yeah I considered it might be the ICM, the motor has almost 200k on it and ive replaced the coil and Opti so far. I need to check to see if the Opti is sending signals first.
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Old Mar 26, 2010 | 11:14 PM
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Any other ideas?
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Old Mar 27, 2010 | 01:05 AM
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opti harness goes down the passanger side of the intake, you check it all besides just the connector?

does it keep trying to crank? might be an ignition switch
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Old Mar 27, 2010 | 01:08 AM
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Originally Posted by myltwon
opti harness goes down the passanger side of the intake, you check it all besides just the connector?

does it keep trying to crank? might be an ignition switch
No just the harness its self, but will look at it more.

It cranks and cranks but wont start. Any way to test that?
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Old Mar 27, 2010 | 05:52 PM
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Ok, ignition switch is good, did the Opti check with shbox how-to and Terminal A only had 4.63 DCV and Terminal D had 0.02 DCV.

Now he says if there is less then 10DCV its the fuse or coil...the coil is a 2 month old MSD unit and I switched it out with a working GM one and still no start. The ignition fuse is perfectly fine too.

Did I **** up with reading the DCV on the harness? Im really close to setting this thing a blaze.
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Old Mar 27, 2010 | 06:43 PM
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I would say ICM and clean all your grounds, check that ground wire form the ICM to the frame for corrosion, that's the problem I had with mine.
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Old Mar 27, 2010 | 06:53 PM
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Originally Posted by SS#502
I would say ICM and clean all your grounds, check that ground wire form the ICM to the frame for corrosion, that's the problem I had with mine.
Will check that ground. Thanks
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Old Mar 27, 2010 | 08:45 PM
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also make sure the icm is properly secured to the coil bracket
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Old Mar 29, 2010 | 01:40 AM
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Get her runnin' yet?
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Old Mar 29, 2010 | 09:52 AM
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Originally Posted by SS#502
Get her runnin' yet?
No not yet, between the random rain here in FL and my Exam coming up, ive been busy with studying. I will bump this thread when i figure out the problem though.
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