Anyone had tach problems when swapping an obd2b motor and wiring harness into an ond1 car? I just swapped a 2000 b18c1(obd2b) in my 95 (obd1) LS and the tachs not working, anyone know whatto do? someone told me i had to splice into a wire on the dissy, but wasn't sure what color wires to what color wire and haven't found anything in my helms manuals yet or from searching on here.

 

I'd say you are using the GSR engine harness, you will need to make the connection for the tach from the distributor to the driver's side shock tower plug (blue wire).

 

thanks

 

tap the empty spade connector inside your distributor into the blue wire on the harness. your current diz probably did not have this connector attached to a wire because the ecu that the motor came with fed the tach signal from the ecu not the distributor, but the distributor didnt change so that spade connector is still there.

 

thanks, I solved the problem yesterday and you're right, OBD2b do not have the the blue wire for the tach coming out of the dizzy's plug, only going in so there is an empty slot, just put a pin in the place and ran the wire to the driver side harness and there was a blue wire on the fire wall side and an empty slot on the OBD2b engine harness, tach works now, think I'll post some pics incase anyone else runs into this