i need help with an carb to efi rewire and fuel pump conversion - Toyota Nation Forum : Toyota Car and Truck Forums

mikejax19 · 04-09-2011, 06:03 PM

so far the majority of the wiring has been plug and play but i need help with the efi and the gauge cluster. im droping a an efi 4afe into an 88 sr5 that had as carb 4af in it . i pulled the 4afe from my old geek mobile(a 90 rolla sedan). so the gauges wont fit in the sr5. from what i can tell the harness running back to the fuel tank on the sedan has the rear speakers and the sending unit on it so my main question for the efi is one can i get away with running switched 12v to the pump and will and can i use an inline fuel pump? and then as for the gauges how are they wired in. do they run from the from the kick pannel fuse box or are they run from one of the cable that are next to the computer?

eage8 · 04-10-2011, 06:37 AM

when I did the swap in my '89 SR5 I used to stock gauges just fine. what's wrong with the SR5 gauges? Are you using the whole dash harness from the sedan too? The gauges aren't powered by the ECU. Your stock Sr5 probably doesn't even have an ECU

An inline fuel pump should be fine. the filters are tricky though.

First you have to upgrade all the lines to EFI spec. They need to hold a lot more pressure. You'll also need some sort of filter on the line. The stock EFI system has 1 filter in the tank (which you don't have) and another by the engine bay (which you have, but it isn't enough for EFI)

mikejax19 · 04-10-2011, 11:18 AM

min has an ecu. but my real concern for the gauges is i dont know what powers them. there is a green plug with i want to say 16 pin wholes in it on the sr5 and the sedan has a gray plug with 20 pin wholes in it. i was wondering if that is what powers the gauges. and for the inline pump can i just run switched 12v to it to get it to run the car?

eage8 · 04-11-2011, 10:19 AM

Yeah, mine did too, I think only California models had ECUs though. They don't actually do anything, just turn on the check engine light if anything's wrong

You need to power the pump with a relay... but you can switch the relay with switched 12V, it shouldn't be a problem. I think that's how it is stock, just the ground side of the relay is the ECU's fuel pump pin that grounds it.

Are you using the sedan's dash harness? if not, than the gauges will be fine.

mikejax19 · 04-13-2011, 03:28 PM

i dont know which harness is the dash harness. im using the original fuse box on the driver side kick panel but i just dont know what the extra plugs are for by the ecu