I have a 91 converted from a tbi to a 92 s/d tpi. i have a 5 spd and think the tpi came from an auto. factory harness was changed and all. i have (for now) 4.10 gears out back.

the speed was off but working since the conversion last year. recently while driving the car lost power and limped home. the speedo went out at the same time. i got the car running again, a mild surge but the speedo isnt working. i looked underneath and its plug in.

i read some threads on the vss diffrences between tbi and tpi. im not sure if i need to replace the vss now. i wasnt exactly sure how it should be "repinned" in the connector either. should i repin it first to see if it works or is there a complete other solution i didnt see?

 

The VSS is the same between V6 MPFI, V8 TBI or V8 TPI. However, there IS a difference between a VSS for the automatic transmission and the 5-speed (that one is smaller).

And if you are repinning the VSS connector, polarity does not matter. The VSS generates an AC wave for the speedometer (and ECM) anyway.

 

'165 MAF TPI and TBI ECM 's use a 2000 pulse VSS signal

'730 SD TPI ECM (90 - 92 ) use a 4000 pulse signal

 

im running a 730 ecm. i have not changed anything on my trans. i dont know if the connection messed up the vss or if it went out on its own. so what do i need to do to the harness or connector before replacing the vss?