I'm finishing up a LS1 swap on 1991 GTA and I'm having trouble finding the wire to hook up my tach output to. I also am not sure if my programer changed my tach signal to a v8 signal so do I have any other options other than having my ecm redone.

 

Connector C105 (also the #10 wire from the Red PCM connector), white.

http://www.team3rdgen.com/modules/3r...s/99wiring.jpg

Or, did you mean the chassis wire?

C100, D6, also white.

If the PCM wasn't reset, your only choice is an aftermarket tach set on 4 cyl.

 

^^^ good info to know

 

what about using one of these http://www.dakotadigital.com/index.c...rod/prd127.htm

 

You can use the box but if the tuner forgot something make him fix his mistake

Beware birds usually require the booster wire to get the tach working. Wrong tach value means tune issue, no tach means booster needed