Hello all, I have done a 92 z28 swap into my 96 c1500. The short block is bored and stroked making it into a 383, by a professional engine builder. The intake I completely re-did with new gaskets, all new sensors (tried 3 dif map sensors), new msd coil and msd distributor, 58 mm bbk t.b., all new hoses, egr block off plate, deleted the charcoal canister, new z28 fuel pump (43 psi) new fuel filter along with new pressure (3/8) and return lines (5/16), new regulator and 2 sets of new injectors (1st set 28 lbs, 2nd 24 lbs) new etc,etc,etc... My tuner guy via online says the computer can not take away enough fuel along with him bumping up the injector pulse width. He deleted the egr and knock sensor out of the computer (not sure why the knock?) It's running crazy rich. Brand new plugs were fouled and when I bore scoped the cylinders there was a small puddle of fuel in the corners. Reving up engine without a load revs great. Driving it accelerating it hestitates, misfires and sometimes back fires. I exhausted all of my options and have no clue about this old technology. Can someone please point me in the right direction?

 

Well if pressure checks out at 43 psi or so, and injectors arent stuck open, then you need a new tuner

 

Lol It has crossed my mind

 

Engine swaps are always prone to setup issues. Grounds not hooked up, incorrect hookups, voltage issues, etc...

Before going after the tuning, I'd make sure the ECM is getting all the inputs and voltages it needs...

http://chevythunder.com/fuel%20injec...20(ecm#1227730)

Put negative probe of your multi-meter to the negative ground post on the battery and then use the other probe to test the ECM connectors per the above link.

 

What does your guy mean "take enough fuel away along with bumping up pulse width"? Adding pulse width adds fuel, so of course that wouldn't help.

Your best bet is let a professional tuner, with a dyno and gas analyzer, get his hands on it in person and just pay him for his time helping with the diagnosis, then for the tune, because you clearly still need one anyway. This sort of thing is very hard to solve without seeing the vehicle, and usually fairly easy to solve if you can get your hands on it while reading sensor data. If a tuner can't help you troubleshoot, I wouldn't pay him to tune either because he probably doesn't know what he's doing.

Besides, you don't want to melt your catalytic converters, if you have them, by screwing around while running that rich. Cats aren't cheap. Buying more injectors and sensors that may or may not help isn't cheap. Good dyno shops aren't cheap either, but they have the tools to do it right quickly, so you probably only need to pay them for a few hours once, maybe twice if you have the wrong parts the first time, plus you get all kinds of readouts if you're into that.

The only checks I'd do first are basic electrical system checks, then resistance checks on sensors and injectors, if those are all to spec, it's probably in the controller as long as your injectors are even somewhat close to what they should be. If you have cats and you've been using it a lot, you want to look and make sure your cats aren't already melted, or plan on one troubleshoot session and one mapping session. Mapping with a restriction in the exhaust would be a complete waste of money.