I have a 87 GTA with a 350 TPI that had a engine fire. I used a engine wiring harness from a 87 IROC with TPI. And the headlight harness from a 86 T/A. The problem I have is that the tach reads high. I know this because when I downshift into 3rd I bury the needle. I have the 700r4 with 3.27 gear ratio. The exact same as in my IROC. Am I missing something? The dist. is out of a 87 Monte Carlo SS. Any Ideas?

------------------
89 Iroc 350 TPI,
Forged pistions
Comp roller Cam .510 lift 230dur
Flowmaster exhaust
Dart Iron Eagle heads 200cc runners 64cc chambers
MINI RAM SOON!!!!!
stock TPI for now 24# inj
87 Trans Am GTA 350 TPI
had engine fire
SHE NOW RUNS!!!! GREAT!!
Flowmaster exhaust
LT1 Injectors

 

ANYBODY????!!!!??? I have since hooked up a digital timeing light and at 6000 rpm's on the dash the tach on the timing light read 3000 rpm's. PLEASE HELP!!!!!!

------------------
89 Iroc 350 TPI,
Forged pistions
Comp roller Cam .510 lift 230dur
Flowmaster exhaust
Dart Iron Eagle heads 200cc runners 64cc chambers
MINI RAM SOON!!!!!
stock TPI for now 24# inj
87 Trans Am GTA 350 TPI
had engine fire
SHE NOW RUNS!!!! GREAT!!
Flowmaster exhaust
LT1 Injectors

 

The tach (white wire) is driven directly by the white wire between he coil & distributor module, correct? Maybe you need to install a tach filter.

------------------
Tim

1992 Z28, 305 TPI 5 speed, 12.1 sec @ 114.7 mph

1984 Berlinetta 305 TPI Auto, 13.8 sec @ 99.7 mph