Hello!

[Dukes164]

Well I was given a tip to talk to a local guy named Ellis that is supposed to be really good with lt1's and it turns out hes been trying to figure out whats wrong with this stupid car too! The previous owner had been bringing it to him and actually still owes him $300 bucks. Anyway this cars had the problem since day one and Ellis saw the same event of the PCM shutting down. Apparently the PO had taken the car back to the guy that either made the harness or just installed it and he was told that everything is wired fine and everything is working correctly.

I double checked all the pins on the PCM connectors just to make sure nothing major was missing(didnt trace any wires). Only thing I found was that the tach output wire wasnt there yet my tach still works (have to investigate that).

[Dukes164]

Borrowed a PCM from a friend today, didn't fix the problem...

[steveo]

these pcms don't really have failures like that, but still good to try.

tach output is filtered, probably your tach is spliced to coil negative, which is acceptable.

this is definitely a fundamental electrical issue.

im still thinking something is gettin' yanked at WOT. i can't correlate it to anything else.

other ideas...

give it a couple good hard stabs of throttle as someone is watching under the hood

unhook your alternator positive and do a wot run

add a chassis to ecm ground

jump positive power to coil positive (bypass ignition switch and everything)

[Dukes164]

these pcms don't really have failures like that, but still good to try.

tach output is filtered, probably your tach is spliced to coil negative, which is acceptable.

this is definitely a fundamental electrical issue.

im still thinking something is gettin' yanked at WOT. i can't correlate it to anything else.

other ideas...

give it a couple good hard stabs of throttle as someone is watching under the hood

unhook your alternator positive and do a wot run

add a chassis to ecm ground

jump positive power to coil positive (bypass ignition switch and everything)

Yeah, I didn't really expect the PCM to fix the problem just had to knock another piece out of the equation. You were right about how the tach was wired.

I watched the motor while having someone rev and the motor is fricken solid it barely moves if at all, we even foot braked the clutch and it does not move. I did notice what i would call a lean pop when it was revved up.(only happened twice and I saw a nice flame come out of the intake both times).

Disconnecting the the alternator didn't do anything.

When you say to add a chassis ground do you mean a ground on the ecm box? or just adding a chassis ground to where the ecm is ground wires are grounded?

Didn't have time to put direct power on the coil today...