dori-oni

i have a 92 sc300 with gte swap. ok well ive checked everything and ive come to the conclusion that its my fuel. well car cranks over starts for a sec. then shuts off, my buddy was telling me that it could be the fuel pump relay, well i put the car in the on position and i dont hear the fuel pump from the trunk. i carank it like 10 to 20 times then it starts then i hear the fuel pump, i checked on the driver back panel there is a unit called the fuel pump control part number 89570-24010. the 12v mod was done to it, could this be the problem that the control unit went bad is there anything else that could go bad that would cause the fuel pump not to start becuase when the car is on the car runs perfect so i know the pump is working up to par??

dori-oni

anybody???

trancuongv

iTrader: (3)

you can bypass the fuel pump control unit. search that and it will lead you how to do it. i believe splicing two wires together. try that out first.

dori-oni

isnt that bad tho??? and can you lead me in the right direction, wait i allready have that done where it constantly runs 12v i allready have that mod done where u cut the 2 wires and cap then, problem is in the on position the fuel pump doesnt come on, but the wierd part is that when i finally get the car started the ful pump works fine and i can hear it

dori-oni

so then if the 12v mod was done what could cuase my problem of no fuel at start up??? or could it be something else not letting me start the car up, whats wierd is that it worked perfect before

jm94tt

Any codes? 1j or 2j?

dinhnerz

Why not check if there is fuel at the rail. Easily pull off the fuel return line on the rail. If there is fuel coming out. Your fuel pump should be fine. Then move onto injector problems.

dori-oni

i dont think that is it i dont hear the pump at all from the trunk i have the twin supra densos

dori-oni

ok i connected the wire from B+ to fp terminal and put the ignition on and i hear the pump when i pulled the wire out and put it on position i dont hear the pump so i assuming the fuel pump ecu is not working properly i guess any other inputs on this??? so since i put the the wire between the 2 and the pump ran when the ignition was on should i bypass the fuel pump ecu and just keep the wire between the B+ terminal and FP terminal to constantly run when the ignition is on?? will i have a wire issue like catching on fire??

jm94tt

No codes? I had the exact same issue with my 92 sc400 with a 1jz. Car would start for 2 seconds and die, I could get it running by repeating this about 20 times, but it would barely run until it warmed up to operating temp. I had already done the 12v mod and the fuel pump would run fine. I replaced all of the electrolytic capacitors in the ECU and the issues went away. I had codes 22 (coolant temp sensor circuit malfunction) and 21 (main o2 sensor heater malfunction). After replacing the caps, both codes went away. I am guessing the ECU was dumping way too much fuel for the engine to start and run correctly until it warmed up.

dori-oni

i get what your saying ut mine is the oppisite becuase my fuel pump doesnt run in the on position anymore only sometimes so it has no fuel to spark. what i dont understand is why the pump is not coming on even with the 12v mod but does turn on constant with the diagnostics plug

miraluna

iTrader: (2)

I have same problem... I have 92 SC300 and I did 12v mod... Have you figure out why this happened... how did you fix this problem?

miraluna

iTrader: (2)

I fixed it... undo the 12V mod....

codetoad

iTrader: (2)

I have a '92 SC 300 manual and i have a similar problem.

I changed out my Fuel pump to a walbro unit a while back. My car started shutting off on me eventually while driving, and wouldnt start. I figured it was the fuel pump ecu. I tried Jumping Fp to B+ worked and got the fuel pump running again, abnd it worked pretty good for a while, but the fuel pump would remain on, with the key off, engine off, and drain the battery.

Eventually, the car wouldnt start at all, so I ordered a fuel pump ecu (which may be faulty as well.). It started for a little bit, but then I stopped hearing the fuel pump operating with the key on. I found a blown EFI fuse and the EFI main relay to be faulty and replaced them.

With all of that replaced, the car started up good, ran for a little while, then after about 30 mins of running it, the idle started bogging really low, like 500 rpms and less, and then died. When i turned the key off, the fuel pump continued to run for a little bit, but I think my battery voltage (might be shot) dropped too low for the fuel pump to operate and shut off.

I'm pretty sure the fuel pump kept on running even with the car off, which has been a longstanding issue with my car now. I don't know what is causing it, and i'm starting to wonder if my '92 5 speed ECU is faulty now and needs to be replaced.

The car wouldnt start up again when i tried, the fuel pump was not coming on, and the EFI Relay is getting super hot, even with the car is off.

Anyone know why my Fuel pump is getting power with the key off and why the EFI relay is getting super hot with the key off? I'm stumped, and it's draining my friggin battery and causing more headaches.

dumdumgreg

iTrader: (5)

Codetoad
were you able to come up with a solution, I'm having the same exact problem now, sometimes the pump would stay running with the key out, and it always dis after ~30 mins of driving