My friend owns a 91 Z with a 383. A quick rundown of the engine looks like this: Dart Pro 1 aluminum heads, LT4 Hot cam, 10:1 compression, bosch fuel pump good for 550hp. He has a jacobs ignition box and coil. He is running a 58mm throttle body with TPIS large tube runners and base, afpr, 24pph injectors. He also has a custom chip from Ed Wright.

Now for the problems. He is experiancing backfires when under load at medium to heavy throttle. The engine is also running rich. It also boggs at low rpms and has horrible throttle response until he hits 3,300 rpm. We have checked and changed the plugs and wires, and have the base timing 0*. Any ideas what it could be? We think the cam may be set in there wrong, is that a possibility? I know theres not much info here, but any help would be appreciated. If you guys need more info, let us know, cause he really needs to get thiis beast running the way it's meant to. Thank you, Roy

Did you verify that the ESC is working and the timing hunts on its own?

shouldnt base timing be 6* BTDC?? that is what I have mine set to on my 383 with the LT4 hot cam.... I have great throttle response and it isnt even tuned properly... does he have a cat? if so it could be clogged from running rich. how do you verify it is running rich? smoke? smell? make sure the fuel pressure regulator is still set properly, I had one crap out on me. Check to make sure the TPS is adjusted properly... .54 volts at 0% throttle. pull all the plugs and make sure all of them look consistant... I had one injector at one time not firing AT ALL, so I was dragging on cylinder. good luck with it

Thank you for the responses. Had a quick question. Does winaldl work with tpi? You'll have to forgive me, I'm a tbi guy, and I'm not really over on this board to much other than when my friend needs assistance. I know it supports the 7747, but wasn't sure if it only supported tbi. We want to take a look and see what the computer's doing.

yes, winALDL works with TPI, I have it connected to my 87. on the 91, I believe there are just two wires that need to be connected, on mine I know there are 3, but that is because the MAF cars need a resistor in one of them. Head over to the DIY prom section and search for something to do with the cable, it should tell you which wires to tap into.

Cool, that's what I thought. I know the wires go to pins A and E for the 8746, but when we tried on my buddy's TPI, there was no pin in the E slot, so we were thrown off a bit. I will do a search on the DIY board and hopefully find which pins to use. Thank you