LTX and LSXPutting LT1's, LS1's, and their variants into Third Gens is becoming more popular. This board is for those who are doing and have done the swaps so they can discuss all of their technical aspects, including repairs, swap info, and performance upgrades.
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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.
__________________ 1991 Z28 Engine: '94 355 LT1, GM hot cam, 1.6 RR's, Ported Heads, Dyno Don's headers, #30 SVO injectors, stock internals with skirted pistons. Drivetrain: '95 T56, pro 5.0 shifter, hayes clutch, Stock 10 bolt with 3.42's Suspension: LS1 front brakes, Spohn SFC's, hot part LCA's. 265/40/18's up front and 275/40/18's out back on 18x9.5 c6's 335RWHP 339.8RWTQ
It may be worth trying to find a stock LT1 harness and trying it....
Or give Speartech a call.
If the ignition wiring isn't hooked up properly, you will get a no spark, might want to also make sure the pinouts on the PCM connectors are for the PCM you have, they changed between years, especially if you still had the C100 connector on the harness.
Maybe i wasnt clear, but im getting good connections between the opti and the computer. I just dont know if this new opti still isnt pulsing or if the computer has a short and wont signal the ICM.
Yesterday i tested continuity from the end of the opti harness, back to the black connector on the PCM and read good on all 4 wires. Today i decided to do the same to the ICM. pin B5 on the PCM was Ignition Control, a white wire. The wire on the ICM side was lt green, so im like wtf that doesnt make any sence and obviously i had no connection when i tested it. So i call speartech and ask them what the deal is and he goes through the skematic with me and tells me which wire it should be. I tell him i get nothing when i test it with an ohm meter, and the colors of the wires. He then procedes to tell me that i had the IAT plug plugged into my ICM this whole time and the ICM pluged into the IAT.
Needless to say as soon as i switched them it fired right up!
