fuel pump problem - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

cronux · 01-11-2008, 11:07 PM

so, i just got done doing a dohc swap in my 89 body, and it has a walboro 255, but now, it doesnt even make noise when i turn the key. it'll try to crank, but no fuel at all. what could be the problem? and its not the fuel pump fuse in the engine bay.

zaneithan · 01-11-2008, 11:45 PM

pull the pump and check all the wiring, check your grounds (for the battery too), i had this problem too when i installed my SR, except i relocated the battery to the trunk, the ground wasnt good enough turns out, after regrounding it, the pump primed

idlafie · 01-11-2008, 11:49 PM

Check to make sure your fuel pump is getting power. You'll have to check the Factory Service Manual for the pinout location on your ECU which provides ground/power to your fuel pump.
First check your fuel pump to see that it works. BEING CAREFUL not to expose yourself to any danger, hook the fuel pump up MOMENTARILY to a 12 volt power supply, (such as a car battery). If you hear it whir as you apply power, then you know it works. Next check the wires going from the gas tank/fuel pump area back to the ECU to make sure there are no electrical shorts. An ohm meter or continuity tester will suffice. If they are okay, then check to make sure you are getting the proper signal from your ECU to your fuel pump. I believe the ECU provides a ground signal to your fuel pump relay so you'll have to test the fuel pump relay, the wiring leading to it & for a ground signal from the ECU. If you don't get one, then you'll have to figure out a way to SAFELY bypass the ECU signal to provide power to the fuel pump. I've seen it done before by people with ECU / fuel pump issues. Instead of replacing the bad ECU, they'll just bypass the ECU ground signal and run the fuel pump off another signal source.
Anyhow, hope this helps....
ID

240sxslide · 01-11-2008, 11:51 PM

check the fuse to the fuel pump i had to add a 20 amp fuse to mine when i got the walboro put in

cronux · 01-12-2008, 12:10 AM

well, i bought the car as a shell, with the walboro and battery relocation already done. he had an sr in it, and pulled it like a week before i bought the shell, and it was running before. then i dropped in a KA24DE, and the fuel pump wont work.

idlafie · 01-13-2008, 12:50 AM

So the previous owner had an SR in it? Did the previousl owner remove the harness as well with the SR engine?? Or are you using the existing harness in the car. Usually when people put a SR motor into a 240, they will repin the existing KA harness for it to work. Maybe the harness has been repinned. You'll have to test it to see. Sounds like you're gonna need a FSM to troubleshoot your problem.
Anyhow, good luck!!
ID

SidewayZ-s14 · 01-13-2008, 12:53 AM

Yeah, check to make sure the fuse is still good!(kick Panel). Don't see why it would go out, but you never know!

Good Luck!

cronux · 01-14-2008, 07:40 AM

the guy who did the swap left the body harness intact, and simply changed the engine harness to be a direct plug in. my dohc engine harness and tranny harness connected directly to everything, except there is a 2 slot female connector from the tranny harness, that doesnt go to anything.. i'll get pictures later, but i dont think that it would cause the fuel pump to not get power. isnt the fuel pump just run off the body harness anyways?

cronux · 01-14-2008, 04:37 PM

so anyways, i checked the fuse, good. the relay, (im assuming its the EGI pump, as that was the closest thing to fuel pump??) is fine, the wires to the walboro, 2 of them are getting 12V constant. one is yellow with a green stripe, and the other one is yellow. the yellow wire has a very weak electrical signal, but even after applying a clean 12v constant, the fuel pump still didnt turn on. there are five wires total going to the fuel pump, is their anyone who knows exactly what each one of them are? i just hope its not the fuel pump

lonelydrifter · 01-14-2008, 04:47 PM

When swapping an sr it is required to splice wires from engine harness to body harness. Make sure all the wire colors match up because he would problably have had to De-Pin both the male and female plugs, so his SR harness and the Body harness that is in the car.

But if you take the fuel pump out and give it current and it doesn't turn on then its bad. Try again and double check the wiring up by the fuse box, front passenger side.

cronux · 01-14-2008, 04:55 PM

well, i didnt actually wire directly to the fuel pump, the harness connector that is right before the fuel pump was corroded, and was preventing current to the yellow wire. just wondering here, would it be possible to just have a 12v switch hardwired to the pump, to automatically turn on and stay on when the key is turned? (using a relay and fuse, to be safe of course),

01-11-2008, 11:07 PM	#1
cronux Zilvia Junkie Join Date: Oct 2006 Location: wI Posts: 300 Trader Rating: (0) Feedback Score: 0 reviews	fuel pump problem so, i just got done doing a dohc swap in my 89 body, and it has a walboro 255, but now, it doesnt even make noise when i turn the key. it'll try to crank, but no fuel at all. what could be the problem? and its not the fuel pump fuse in the engine bay.

01-11-2008, 11:45 PM	#2
zaneithan Zilvia Addict Join Date: Sep 2003 Location: NY Age: 39 Posts: 948 Trader Rating: (10) Feedback Score: 10 reviews	pull the pump and check all the wiring, check your grounds (for the battery too), i had this problem too when i installed my SR, except i relocated the battery to the trunk, the ground wasnt good enough turns out, after regrounding it, the pump primed __________________ 1993 240sx fastback (wrecked) 1991 240sx SE fastback Daily Driver status 1992 240sx fastback (???) 1986 Toyota Corolla SR5 Coupe (sold)

01-11-2008, 11:49 PM	#3
idlafie Zilvia Addict Join Date: Mar 2004 Location: ..So Cal.... Posts: 940 Trader Rating: (0) Feedback Score: 0 reviews	Check to make sure your fuel pump is getting power. You'll have to check the Factory Service Manual for the pinout location on your ECU which provides ground/power to your fuel pump. First check your fuel pump to see that it works. BEING CAREFUL not to expose yourself to any danger, hook the fuel pump up MOMENTARILY to a 12 volt power supply, (such as a car battery). If you hear it whir as you apply power, then you know it works. Next check the wires going from the gas tank/fuel pump area back to the ECU to make sure there are no electrical shorts. An ohm meter or continuity tester will suffice. If they are okay, then check to make sure you are getting the proper signal from your ECU to your fuel pump. I believe the ECU provides a ground signal to your fuel pump relay so you'll have to test the fuel pump relay, the wiring leading to it & for a ground signal from the ECU. If you don't get one, then you'll have to figure out a way to SAFELY bypass the ECU signal to provide power to the fuel pump. I've seen it done before by people with ECU / fuel pump issues. Instead of replacing the bad ECU, they'll just bypass the ECU ground signal and run the fuel pump off another signal source. Anyhow, hope this helps.... ID __________________ Weekend Mechanic for my Not-So-Mechanically-Inclined buddies....

01-13-2008, 12:50 AM	#6
idlafie Zilvia Addict Join Date: Mar 2004 Location: ..So Cal.... Posts: 940 Trader Rating: (0) Feedback Score: 0 reviews	So the previous owner had an SR in it? Did the previousl owner remove the harness as well with the SR engine?? Or are you using the existing harness in the car. Usually when people put a SR motor into a 240, they will repin the existing KA harness for it to work. Maybe the harness has been repinned. You'll have to test it to see. Sounds like you're gonna need a FSM to troubleshoot your problem. Anyhow, good luck!! ID __________________ Weekend Mechanic for my Not-So-Mechanically-Inclined buddies....

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01-11-2008, 11:51 PM	#4
240sxslide Join Date: Dec 2007 Location: garden grove Age: 39 Posts: 7 Trader Rating: (0) Feedback Score: 0 reviews	check the fuse to the fuel pump i had to add a 20 amp fuse to mine when i got the walboro put in

01-12-2008, 12:10 AM	#5
cronux Zilvia Junkie Join Date: Oct 2006 Location: wI Posts: 300 Trader Rating: (0) Feedback Score: 0 reviews	well, i bought the car as a shell, with the walboro and battery relocation already done. he had an sr in it, and pulled it like a week before i bought the shell, and it was running before. then i dropped in a KA24DE, and the fuel pump wont work.

01-13-2008, 12:53 AM	#7
SidewayZ-s14 BANNED Join Date: Nov 2007 Location: SoCal 714 Posts: 1,061 Trader Rating: (14) Feedback Score: 14 reviews	Yeah, check to make sure the fuse is still good!(kick Panel). Don't see why it would go out, but you never know! Good Luck!

01-14-2008, 07:40 AM	#8
cronux Zilvia Junkie Join Date: Oct 2006 Location: wI Posts: 300 Trader Rating: (0) Feedback Score: 0 reviews	the guy who did the swap left the body harness intact, and simply changed the engine harness to be a direct plug in. my dohc engine harness and tranny harness connected directly to everything, except there is a 2 slot female connector from the tranny harness, that doesnt go to anything.. i'll get pictures later, but i dont think that it would cause the fuel pump to not get power. isnt the fuel pump just run off the body harness anyways?

01-14-2008, 04:37 PM	#9
cronux Zilvia Junkie Join Date: Oct 2006 Location: wI Posts: 300 Trader Rating: (0) Feedback Score: 0 reviews	so anyways, i checked the fuse, good. the relay, (im assuming its the EGI pump, as that was the closest thing to fuel pump??) is fine, the wires to the walboro, 2 of them are getting 12V constant. one is yellow with a green stripe, and the other one is yellow. the yellow wire has a very weak electrical signal, but even after applying a clean 12v constant, the fuel pump still didnt turn on. there are five wires total going to the fuel pump, is their anyone who knows exactly what each one of them are? i just hope its not the fuel pump

01-14-2008, 04:47 PM	#10
lonelydrifter Zilvia Member Join Date: Sep 2006 Location: florida Age: 38 Posts: 270 Trader Rating: (0) Feedback Score: 0 reviews	When swapping an sr it is required to splice wires from engine harness to body harness. Make sure all the wire colors match up because he would problably have had to De-Pin both the male and female plugs, so his SR harness and the Body harness that is in the car. But if you take the fuel pump out and give it current and it doesn't turn on then its bad. Try again and double check the wiring up by the fuse box, front passenger side.

01-14-2008, 04:55 PM	#11
cronux Zilvia Junkie Join Date: Oct 2006 Location: wI Posts: 300 Trader Rating: (0) Feedback Score: 0 reviews	well, i didnt actually wire directly to the fuel pump, the harness connector that is right before the fuel pump was corroded, and was preventing current to the yellow wire. just wondering here, would it be possible to just have a 12v switch hardwired to the pump, to automatically turn on and stay on when the key is turned? (using a relay and fuse, to be safe of course),