I just put a 305 tpi from an 86 trans am into a 1990 firebird that had a v6 in it. I hooked up the engine harrness for the TPI.I went to turn the key none of the dashlights turn on nor did the fuel pump turn on. But the headlights,taillights,side marker lights all work is this because i need the wiring harness for the interior for an 86 to make it work or could someone tell me how to fix this problem?

What wires should be plugged into the distribitor?

Also on the ecu theres a yellow case that is attached. It says AC delco Spark plug 4 out buffer do i need to plugged anything in there is so what goes in there?

Thanks in adavance Hope you guys can help me out!

 

You either need the engine harness/ECM from a 90-92 TPI or the dash harness from a 86-86 bird

Engine and dash harnesses must match

Dist gets two connectors, a 4 wire from the engine harness and a 2 wire from the mini-harness that jumps the coil to the dist

If the yellow box looks like this its the VSS buffer box


It means your 90 was a 305 TBI, not a V6 because 3.1's did not need a buffer box to convert the raw VSS signal for the ECM. TBIs used an older ECM which required this

The 86 would have one, but it wouldnt come with the engine harness. Its a part of the dash harness bolted to the inner dash over the ECM