Last night I took the Z for a stroll, and out of no where the car surged like it was about to die, then went back to running like nothing was wrong, when this happened the Check Engine light came on for a split second then went off again. So i'm coasting to a stop light (which was green) and press the gas pedal down some, absolutely nothing happened, the motor was running, and all the sudden died. So I coasted to the parking lot of a park, and looked over all the connections under the hood, no problem found. Tried to crank, and she wouldn't do anything but turn over. I noticed that the Check Engine light wouldn't come on when I turned the key from the off position to run/start...I disconnected the battery for a couple of minutes just to reset the ECM, and when we reconnected the battery and tried to crank it, it still didn't show a check engine light when key went from off position to run/start, but the motor did hit like it was about to start, then just went back to doing nothing but turning over. I also had a scanner to check for engine codes in the car, but even when it was connected with the key on, the Check Engine light wouldn't flash code 12 or flash at all, which makes me think that the ECM is fried. I'm going to make sure the bulb for the Check Engine light is ok in the morning, and whether the ECM is dead or not I think I will go ahead and order the Holley Commander 950 tommorrow, as I need a good tune and the current chip isn't burnt for 24lbs injectors like I have. Car is also a 6 speed and ECM still thinks its an auto, i've heard of this frying ecm's by itself.

Anyone got any thoughts/suggestions?

 

Definately sounds ECM related. But before you go replacing stuff that may not need it, check at the ECM connectors to make sure the ECM is recieving 12 volts constant, ignition voltage, and all the grounds are solid. Might be something as simple as a blown ECM fuse.

 

Checked the bulb for the SES light, it turned out to be OK. So I read up in the GM repair manual, and it said to probe circuit 439 and 340 and make sure they have power, each had none. Checked the ECM fuse, ok...Checked the continuous battery fuse beside the battery in the engine compartment, and it was melted completely, connector was a little charred also. So I replaced the fuse, SES light comes on now, car cranks and runs, but what would cause the fuse to melt, it wasn't popped like it would with a short, so could it still have a short???

 

Definately possible, but usually when you start melting wires and such, the circuit is pulling WAY to much amperage. Have you tapped the ECM circuit for any other accessories or anything?

Being that the ECM circuit is such an important one, I'd still trace it for shorts to ground.

What amp fuse was installed for the ECM? What gauge wire is around the fuse holder? Might want to verify that it's all stock ratings.

 

a direct short to ground won't do that, but a something drawing too much current with too high of an amperage fuse can.
i have seen fuses that have completely melted, others that had 1 leg burned off, if it had the right amperage fuse in it, i would lean toward a bad connection on 1 of the fuse legs. high resistance causes heat, enough to melt a fuse or burn a leg off but not blow the fuse.
you said the fuse connector was charred, i would replace it.