Zombiekiler521

Hey guys I’m new to the lt1 community and I’m having some issues here and need some help I recently got a 96 roadmaster and I didn’t have spark I had no 5v ac at the icm so I changed my optispark I now have intermittent spark I’ve changed the icm and coil pack as well I have 5v ac to icm but when I plug the connector into the icm and recheck I only get .09v ac I also have codes p1351 and p1361 any help would be appreciated

Injuneer

Did you take all the measurement on the ICM harness, per Shoebox's guidelines?

4th Gen LT1 F-body Tech Articles

The voltage on the white wire (pin "B") should be in the range of 1 to 4 VAC.

You need to check the other three wires on the ICM connector if you haven't already.

Zombiekiler521

yeah everything is good i have 2.2vac at the ica harness and i have 12v and ground and my second 12v but once i plug it into the icm and recheck for acv it stays at 0.09vac

Injuneer

What was the mention of the ".... I have 5v ac to icm...." in your first post? That would be out of spec with the engine cranking.

Is the 0.09 V ac value with the key on only, or while cranking the engine with the starter. While cranking there should be an ac voltage, as the PCM sends the pulse signal for the ICM to fire the coil.

The codes indicate a short of open in the white wire circuit. Did you have the old IAC module tested before buying a new IAC? Possible problem with the harness connector, or possibly the new IAC is defective.