Here's my problem...i need help quick. I'm in the middle of swapping out my 89 tbi setup for an 88 TPI setup. When we layed the 2 wiring harnesses side by side, we noticed that the TPI harness has a fuel pump relay and fuel pump boss primer plug (that's what it's called in the haynes manual), and the TBI setup didnt. This means that the plug on the TPI harness has nowhere to plug into. So how is the fuel pump going to come on? I'm thinking that maybe the plug is something that can be bypassed, or i'm going to have to splice the wires off that plug into the wires leading to the fuel pump. What I dont get though is...how did the TBI pump turn on if it didn't have a fuel pump relay?? It had to have some other method. If anyone knows anything, help me out...thanks

 

the TBI did have a relay. there should have been a little resistor on the drivers side firewall that controls the fuel pump. dont know if this is the sam as the TPI or if it will help, but its something.

 

Was it shaped like a relay, but smaller? If so i know what you're talking about.

 

I've read that the fuel pump is actually activated by the Oil pressure switch....if that's so, then Its not absolutely necessary to have the fuel pump relay hooked up....it'll just take longer to crank right?

 

interestingly enough i have had an aftermarket ecm fitted to my RS wit tpi
guy used oem tbi harness and added the injectors to the tbi injector wires ...every other relay except the map sensor(now located in the ecm ) was used as it is attached with the tbi