I am begining to get extremley frustrated with this engine. I swaped a 94 into my 91 camaro.
My problem originated with no spark. I had a brand new wiring harness, brand new coil, a tested good ICM, brand new GM opti, a computer ive never witnessed running.
I did shoebox's opti test, and wasnt getting any AC pulse at the ICM connector. Replaced the opti, and i still get no pulse. I have .4 volts ac at terminal b constantly with the key on. Everything has the power it should.

My computer was tuned by trifecta, which uploaded flawlessly, and when i used his tuner as a scanner i first got code 42, and then code 16. that is when i replaced the opti. Now right now i have no acess to a scanner, but as i said im still getting no ac pulse. Right before i shipped the scanner back i did pull a code 42 again, but didnt think anything of it cause of misc plugs that were probably disconnected. Possible my PCM is bad?

Im at a loss and i dont want to spend 200 on a hunch.

please help

 

The AC signal you are looking for is with the engine CRANKING!. Not merely with the key on.

But I think your problem is more fundamental than that.

 

you should get 1-4v while cranking at the trigger wire, on my 95 its the white wire, not to be mistaken with the white/blk wire.
make sure you have a pulse at the trigger wire 1 to 4v (while cranking), do you have spark at the coil?
when you say the icm was tested good...did some place along the lines of an autozone test it? if so i wouldnt trust autozone for anything...i only buy stuff from autozone like oil, filters, etc unless i just need to get something running like now...

 

well i figured out what it was. i had my iat and icm plugs swaped. lol. i called the speartech and told him the colors of the wires and he figured it out for me. always the simple things.