My buddy has a 1986 IROC, 305 TPI w/automatic. The car runs perfect when in park, shows good voltage, everything is great. As soon as we pull it into gear, voltage plummets, lights go dim, and the car runs like total crap. This is a real improvement over before, but he found a missing vacuum line and replaced it, and now it at least idles in park. I'm at a loss. The only thing that has been removed is the A/C equipment, and we built a custom inlet for the air cleaner. All electrical connections are tight, the MAF is fine, and all sensors are hooked up. Any help is appreciated. Oh, BTW, I searched, and that's why I'm asking here. Thanks.

 

Could be a long shot, but it's possible the Torque Converter is staying locked up or the TC solenoid is being energized when the key is on.

Try the ttranny board for the location of the plugs and disconnect it and try again.

 

Thanks, I'll have him check it out. If/when it does at least run in gear, the lights flash/flicker, and the car runs like complete trash.

On a side note, why does the LB9/700-R4/3.23(when it runs right) combo feel like it pulls harder than his old LO9/T-5/3.73 car did?

 

I think mine used to stall on hot days, now it's cold but idle can vary to the point it seems to stall out. I've built up a habit of slipping into neutral gear to do turns or waiting at intersections...it's less hassle on the motor not engaged to the trans. I have the 350 TPI with auto and it just seems like a cranky race engine that hates going slow... The car really moves smooth at 55 or higher, which is what I love but at the same time, no way to really open the sucker up.

 

That's a fairly common symptom of a lean mixture or excessive timing advance. Keep looking for vacuum leaks. Don't overlook the brake power booster and PCV valve. Disconnect them for test purposes.

 

did you get any water in the charcoal canister? i cleaned my engine compartment and rinsed it with water before and i think i sucked up some water in the canister and tehn after a week it cleared up. just a thought.

 

After exhausting every idea you guys and me threw at him, he finally found the negative battery cable loose. Now the dang thing runs perfect. Now if i just get the Custom CAI done.

 

Sorry. Looks like no one was even close on that one. Glad you found it though.

 

Based on previous experience it's always best to check the battery, alternator, and their connections when you get a problem like that. Basics first

 

Thanks for all the help. A quick Q for you. He had another guy tell him to put a resistor inline with the IAT sensor. Something about slightly richer A/F mixture. It sounded wrong to me, and immediately it killed gas mileage(by like 5 mpg). On my advice, he hooked it up minus resistor, and I'm waiting for the feedback on mileage.

 

Yes, it's a trick that's been used, most here would rather relocate the IAT/MAT sensor rather than use the resistor 'trick'.

 

From what I can tell by hacks of the older (MAF) TPI programs, the IAT/MAT sensor really has little bearing on the fuel mixture calculations. It might add a bit at startup and in closed loop - maybe. It seems to have a lot more influence on the SD setup.

 

Very good point, but didn't someone say they found it had an affect in PE?