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View Full Version : urgent, thanks! fuel pump not priming, ok to run constant on?


wrxkyle
06-20-2010, 09:18 AM
hey so i have to drive my car out 250 miles to west virginia from virginia, and the fuel pump wasn't priming last night, realised i hadn't hooked up the black pink witre for it and the rest of them, so i hooked them up and it worked, fired up and ran right, i shut it down and backed it up to get to a bolt and it died, all the connections are there, i'm thinking it's possible the brown 12 sensor output could have shorted with the blackpink ground would that kill the ecu?

can i run the whalbro jumpered to 12v positive constant for 4 hours while driving or will that overheat it and kill it, any other problems? could i just ground the black pink and call it a day for now? i know this isn't best but just to get me to wv then i can trouble shoot more.

when i ground the black/pink the fuel pump runs constant and the car runs like normal, i'm guessing the fpr just sends the excess fuel back to the tank, but i don't seem to be getting ground to it at the ecu. where(if at all) are there changes in connection between the black/pink at the ecu and at the front of the car

where/what other relays are there in that loop of the fuel pump output that i should be checking?

dude thanks so much for helping on this one our work unexpectedly moved and the trailer my friend had now has his own 240 on it he just got so my plans of trailering it up just got the shaft hardcore

R33E8
06-20-2010, 09:31 AM
go for it.. it will be fine..

ATLspeed
06-20-2010, 10:17 AM
To my understanding the fuel in the tank is what keeps the fueld pump cool. If you are going to "hot/hard-wire" it at least use a relay with a fuse

wrxkyle
06-20-2010, 10:45 AM
yah i know the fuel in the tank keeps it cool but i know it normally doesn't run at a 100% duty cycle. if it comes down to the wire i will jumper the black/pink to ground and do a lot of praying.

R33E8
06-20-2010, 12:23 PM
I'm pretty sure it does run at 100% duty cycle... some newer cars like STI's or cars with no return lines like srt-4 vary the power to the fuel pump..

Om1kron
06-20-2010, 12:25 PM
I'm pretty sure it does run at 100% duty cycle... some newer cars like STI's or cars with no return lines like srt-4 vary the power to the fuel pump..

You're pretty sure, or you're 100 percent he will be fine and this wont have any consequences?

I'd make sure to stand behind one or the other if you don't have personal experience and just armchair mechanic knowledge.

:s101:

punxva
06-20-2010, 12:32 PM
running it on a switch with a fuse is fine, it does pulse the current on the stock setup. My old track car was running it on a switch with a walbro for almost 2 years with no problems. Now that same walbro is sitting in my new track car and works with no problems.

R33E8
06-20-2010, 12:58 PM
nvm........

projectRDM
06-21-2010, 08:14 AM
The fuel pump in the 240SX runs full song all the time, fuel is regulated back to the tank if there's too much in the rail. Most cars are like that dating before 2000.

Returnless fuel systems vary the voltage to the pump, eliminating the need for the return, but you won't find that on any Schassis.