Ok, a while back I had posted about this LT1 project that I bought and I rewired the 96 motor all back to 94 LT1 wiring and computer and the motor ran great. so I preceeded to put everything back together from radiator to fan and all the hoses and crap. As well as the interior and driveshaft that was out of the car when I bought it. I went for a drive around the subdivision I live in while topping off the fluid for the trans as I went ahead and changed the filter and fluid in the trans while I was under the car and it looked like crap in the pan so likely the trans won't be there long. Any way while driving the motor ran good and strong and then it just up and died and here I sit about .5 mile from the house in a car with no tags or insurance or anything of that nature. I assumed it was out of gas since the needle was near E and I could hear the fuel pump and it just died like it was out of gas. Put gas in it and it did start and drove home ok but it didn't want to run. every time I got into the throttle it wanted die like it didn't have enough fuel pressure or something as I have had that problem with a TPI car once. so today, I checked my fuel pressure and its a little over 40psi so I am getting plenty of fuel at the rail and I checked my spark at the coil and getting strong spark there. I thought maybe a bad MAF sensor so I unplugged it so it would run off the MAP which is the way I was running the car before I put it back together and the car started and I let it idle for a few minutes and then cracked the throttle and did some WOT revs in the driveway and about the 3rd time I did it just bogged and died and hasn't fired up again. Not sure what the hell is wrong with this thing. I am charging my laptop and downloaded the TTS Datamaster software although I havent tried datalogging a $EE LT1 before. Any ideas on things to check would be appreciated.

 

Today, I hooked up TTS Datamaster $EE and fired the car up and it run for nearly 1 minute before it went into its bogging and dying routine began. The only codes I got from the computer during that time was code 48 for the MAF which I did have unplugged but won't run either with it plugged in and now its currently plugged in. It also had code 43 ESC which I thought was odd but since I have great spark I don't think that is my root problem but I thought it might indicate a faulty PCM so I went and got my spare and plugged it in and even though I haven't a clue what that PCM came other than its the same service number as mine, I figured I would at least get a different problem. But hell no, I fired it up and it ran about 6 seconds and died. I also read the original PCM with Tunercat $EE and turned off the VATS just to be sure it wasn't some weird VATS issue and that didn't change a thing. I also flashed the original Firebirds programming to the unknown 16188051 PCM and that didn't change anything either. I also checked the ground wires that I connected over by the ignition coil since that is I believe the only ground wires there are on the engine harness that at least goes on a bolt like that. I don't know about the wires that run into the passenger side dash although all of those are connected. I don't have any plugs just hanging out in the air not going to anything.

Guys I need some help with this thing. I can't figure out why I have good spark at the coil and good fuel pressure at the fuel rail but no run.

 

DTC 43 sets when there is an electrical fault on the knock sensor circuit. Has nothing to do with "great spark". Wouldn't cause the hard start problem.

Are you sure the fuel pressure holds above 40psi when you try and put the engine under load?

Can you post the data log?