I am in the process of completing a TPI swap in my 1990 rs and i am having an issue with the fuel pump circuit not functioning.

THE FACTS:

-The car is a 1990 Camaro rs and came with a 305 TBI auto.

-The engine and wiring all came out of an 87 Trans Am Gta, and it is a 350 MAF TPI auto setup.

-It has all new sensors

-All of my relays are in working condition

-All of the sensors and plugs has been appropriately placed

-The fuel pump has been replaced to an 87 TPI pump (it has been tested and works fine)

-The Car wiring worked perfect with the last engine harness

-The Trans Am motor and Harness had no issues.

-The Trans Am motor blew and i had the motor professionally rebuilt. I then proceeded to swap the setup into the 90 rs because the 305 tbi blew also

THE ISSUE:

-Something is wrong with the fuel pump circuit.

-Everything else has been tested for power and ground and works correctly

-The sensors and plugs have all been checked and rechecked based on appropriate diagrams

-The pump will only turn on if it is powered with a jump wire.

The main issue is the fuel pump does not turn on when the key is turned to the on position. I need for the pump to turn on and function correctly.

Where could my problem possibly be? Could it be because i put an 87 harness in a 90 car? Thus causing a connection problem at the bulk head?

I have ran out of options and ideas and i could really use some help. Thank You all.

 

on my 89, the wire your wanting is the small red one on the relay....

it is the one that put 12v key power to the relay, a relay is nothing more that a way of using a small amount of current to power a large amount of current...
my guess, is a loose wire on broken connection between the c100 and the relay, time to start wire tracing!

 

we tried that. see its wierd...actually wat we did was, we found that wire and jumped it from there, on the relay, to the car's fuel pump wiring. and the pump turned on. it just wont work with out a jump wire.


wait wait...c100? is that the correct term for the bulk head? if it is i see what yur saying.

what weve been wondering is if the 90 rs car side bulkhead and the 87 gta motor side bulk head have different pinning locations for the fuel pump circuit...could that be an issue?

 

yes, most defanantly.... find the red wire, small coming from the c-100 on the firewall bulkhead, (the bulkhead is called the c-100) try applying 12v to that wire, it should energise the fuel pump, if it does then ya know thats the wire ya need to connect to your relay...