John Galt

I have tried to search the forums and haven't found a thread for this, so I'll start my own. I have an 89 iroc with the 5.7 tpi setup. It runs like crap and I'm sure I have several problems but I can't figure them out so I'm trying stuff to try to track it down. When the throttle is opened initially after starting the car it will cause a backfire in the intake. Acts like it is not getting enough fuel to keep up with the air coming in. I checked the TPS and voltages for idle and WOT were correct. Time has passed and the engine adjusts after a few minutes of driving, and thought it does not backfire it still does act as if there is not enough fuel getting to it. I have made a cable and hooked up winaldl and just noticed while looking at other things that winaldl is reporting different voltages from the ecm than are actually happening. WOT in reality is being perceived as 31% throttle. I streched the cord under the hood and set my laptop there and plugged a multimeter into the TPS to measure. Under the hood the voltages are normal and the ecm is reporting about 30% of actual voltage. I would look for some way for the WinALDL to be giving me an error but nothing indicates this, and the answers fit with the way the car drives. Is there any cause any one can think of that would make this drop possible after the signal leaves the TPS or is a bad ECM the only option for this.

I have recently replaced the injectors, fuel pressure regulator, fuel pump, EGR, MAF, spark plugs and wires, not entirely just trying to fix this but the car has many problems and I'm trying to catch them one by one. Currently I have a swich that turns off voltage to the MAF so that it is possible for it to be driven for the first 3 or 4 minutes till it warms, and then switch it back on. That's a ghetto solution for sure but it can be driven this way. Any ideas would be appreciated.

John Galt

Update: Tried a new ECM because I couldn't wrap my mind around anything else that could do this, problem solved. Along with a few other problems. I'm pretty close to a smooth running car now.