95 z28
 

I have a 93 z28 with a 95 z28 wiring pcm etc…t56 long tube headers motors stock I’m having trouble getting spark I have power to my coil and power in the wiring going to the plug for my opti spark what would cause my opti not to work I just replaced it due to the same issue and it wasn’t a bad opti…

Re: 95 z28
 

Try the first part of this test (ICM Harness):

courtesy of Shoebox

The key to verifying the Opti signals is the voltage on the white wire (terminal B)

4th Gen LT1 F-body Tech Articles

Have you scanned it for codes? Is your 93 DLC wired correctly to allow you to pull codes w/ an OBD-1 scanner, or scan software?

When cranking the engine with the starter, does the tach needle move up ~200 RPM? Did you rewire the tach to accept signals from the PCM, instead of from the 93 coil/filter?

What brand Opti did you remove, and what brand did you replace it with? Did you check the end of the short Opti harness connector for corrosion, assuming the new Opti did not have an integral “short” harness?