451stroker

I have an LS1 in a 1981 Trans Am. I originally ran the car with a modified Camaro harness and a computer programmed by PCMForLess. The car never ran right and the harness had an intermitant short. I decided to stop being cheap and bought a harness from Street & Performance and also let them reprogram my PCM. Long story short, the car still doesn't run right. It idles kind of rough, runs rich, and stalls when it is put into gear. The only way I can keep the car running in gear is to unplug the power brake booster. This really has me stumped. Am I not getting enough vacuum? Does anyone know how much vacuum the MAP sensor needs? I also have 2 used O2 sensors, but both seem to be okay when I use my OTC scanner. Also, I am not getting any trouble codes. The cam is similar to LS6 specs, so it's nothing radical.

Any help on what to look for would be greatly appreciated.

Thanks!

John

Frost

iTrader: (45)

try opening the throttle blade a tiny bit at a time and doing the reset for the TPS (turn key on with TPS unplugged, turn key off, plug TPS back in) ... you will know if you get it too high, it hang coming to idle. It's your best bet with no tuning software to help the idle.

451stroker

Finally fixed the problem. I had the vacuum hoses routed incorrectly. I had a hose running from the front vacuum port behind the throttle body to the rear vacuum port underneath the MAP sensor. From that, I had spliced a line to the fuel regulator. All along, I was confused by there being a vacuum port underneath the MAP sensor. The past engines I was familiar with always had an external MAP sensor mounted off of the engine that had a vacuum line going to it. I didn't realize that the LS1 MAP sensor plugs right into the intake. I basically had manifold vacuum going to manifold vacuum and was also trying to provide vacuum to my fuel regulator from this tap.

The car runs great now.........finally!