Ok, I'm back into a z28 after selling my old maroon car 4 years ago.

I picked up a real nice 94 z28, red, black ZR1s, 6speed, 4:11 gears, leather, t tops. The guy I got it from attempted to do a motor swap from a 93 z28... So there is no MAF sensor present. This other motor is built with paper work to prove. Forged internals, arp fasteners ect ect. It's cammed, but he didn't know the specs and the paper work doesn't say anything about specs either... go figure. I bought the car not running. The po had bought a full MSD ignition setup for the car and couldn't figure out how to make it work...

My problem is this; this car runs RICH. I'm talking it acts like it is just dumping fuel at idle. Smells horrible. I've pulled the throttle body and cleaned it and the IAC really well. It helped, but not much. I've looked and looked for vaccume leaks with no luck. I DO have one known problem. The passenger side bank has a header leak on the middle 2 ports. I'm working to seal that up right now. Will the exhaust leak cause it to run as rich as it is? My old z28 had a manifold leak, but never ran this bad. But it was also a 94 with a MAF sensor. The complete exhaust is mid length headers, 3inch ypipe and 3 inch the rest of the way back to a flow master. Whats my next stop? Tune? Should I maybe TRY a MAF sensor? The computer was supposed to have been swapped with the motor, but I have no way to really know that for sure. The MAF wiring plug is still present. I need some opinions. I'm kinda stumped. Oh, the speedo isn't working currently either. Busted wire on the speed sensor. I don't think that's a issue with it running rich, but maybe..

Bryan

 

It sounds like you have a ton of issues and unfortunately there's no way in knowing what the previous owner did (or didn't do). It should be easy to identify a 93 PCM (try a Google search) as there are obvious differences between the 94+ PCMs.

Once you've established what PCM you have try doing a scan of what the PCM is seeing. If the motor is built and no tune was installed there's no chance in hell of it running properly (which may be the case).

The header leak isn't doing you any favors either as the O2s are undoubtedly picking up ambient outside oxygen.

The lack of TPS signal will only affect your speedo, nothing more.