No power to fuel pump... need some help. - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

JVD · 05-15-2007, 10:09 AM

Last week I took my car out and parked it for like an hour. When I tried starting it, it almost started then just died(I'm assuming there was still a little bit of fuel pressure). I turned the key to off and then back to on. Fuel pump wouldn't prime. Everything else is fine. Starter's good. All electronics come on too. It's just the fuel pump. The fuse is fine. I tried swapping it out. Fuse is getting power too. Haven't checked the relay yet.

Anyone know what it could be? ECU maybe?

This is on a 180sx with redtop SR btw. Happened on a really rainy day too if that matters at all.

Forgot to mention i tried another pump too. Realized it's just not getting power.

slider2828 · 05-15-2007, 10:13 AM

Just check the wires if there is power going there. You can do that by just taking the cover off the pump and test the leads at the top. But sounds like your fuel pump died. Is it new? Do you have a hatch leak? Might want to take a look at that.

'90RPS13 · 05-15-2007, 10:22 AM

I know its simple, blown fuse?

*NemeGuero* · 05-15-2007, 10:35 AM

Rrreeeelllaaayyyy

NI_YON_Zenki · 05-15-2007, 10:37 AM

sounds like the pump is done, if you have yet to direct power to it, then try-it, nothing to really be worried about, this gives you the opportunity to work with some new components on the street. but make sure all is relatively fine with the components associated with the ignition and fuel. I burned out my rear harness, don't ask me how, I till this day am trying to comprehend JUST how it happened, but I am working with all new wiring, so I feel good for the future. new components are installed and even newer measures will be taken.

Best Regards.

NI_YON_Zenki · 05-15-2007, 10:42 AM

It may not be the relay, if the pump doesn't prime, then it could just be the pump itself, burned out from to much work. if this is a stock unit on an SR, there will be issues, the boost may be set at a higher level, the consistency of driving, strong or at ease, it depends on multiple factors. The relay however may have a burned prong, check that out, make sure you check ALL details before dealing with the obvious, because there just maybe a lurking problem that caused this, maybe not.

*NemeGuero* · 05-15-2007, 10:55 AM

Quote:

Originally Posted by NI_YON_Zenki

It may not be the relay, if the pump doesn't prime, then it could just be the pump itself, burned out from to much work. if this is a stock unit on an SR, there will be issues, the boost may be set at a higher level, the consistency of driving, strong or at ease, it depends on multiple factors. The relay however may have a burned prong, check that out, make sure you check ALL details before dealing with the obvious, because there just maybe a lurking problem that caused this, maybe not.

Quote:

Originally Posted by JVD

Forgot to mention i tried another pump too. Realized it's just not getting power.

He swapped pumps. DUH!

JVD · 05-15-2007, 11:08 AM

Quote:

Originally Posted by slider2828

Just check the wires if there is power going there. You can do that by just taking the cover off the pump and test the leads at the top. But sounds like your fuel pump died. Is it new? Do you have a hatch leak? Might want to take a look at that.

I didn't bring a meter yet to test for power, but I'm pretty sure there's no power. Tried another pump which was supposedly new and it didn't work. As a matter of fact I just took my spoiler off that day. I didn't cover the holes up because I was just going to pick someone up and then parking it in the garage. I keep thinking this might have caused it...

Quote:

Originally Posted by '90RPS13

I know its simple, blown fuse?

Nope. Checked and re-checked.

Quote:

Originally Posted by NemeGuero

Rrreeeelllaaayyyy

Yes, really.

Quote:

Originally Posted by NI_YON_Zenki

sounds like the pump is done, if you have yet to direct power to it, then try-it, nothing to really be worried about, this gives you the opportunity to work with some new components on the street. but make sure all is relatively fine with the components associated with the ignition and fuel. I burned out my rear harness, don't ask me how, I till this day am trying to comprehend JUST how it happened, but I am working with all new wiring, so I feel good for the future. new components are installed and even newer measures will be taken.

Best Regards.

I think I'm going to just give the new pump direct power so I can get it home at least. It's parked somewhere still. What should I pull power from?

Quote:

Originally Posted by NI_YON_Zenki

It may not be the relay, if the pump doesn't prime, then it could just be the pump itself, burned out from to much work. if this is a stock unit on an SR, there will be issues, the boost may be set at a higher level, the consistency of driving, strong or at ease, it depends on multiple factors. The relay however may have a burned prong, check that out, make sure you check ALL details before dealing with the obvious, because there just maybe a lurking problem that caused this, maybe not.

I might steal a relay from my bros car just to see if it's not that. It was a stock pump on an SR. Boost was turned up from time to time. Haha. It's not the pump though.

Thanks all for the help! I'm going to try some other stuff today when I get home from school to try and figure this out.

NI_YON_Zenki · 05-15-2007, 11:13 AM

I think I'm going to just give the new pump direct power so I can get it home at least. It's parked somewhere still. What should I pull power from?

____Pull it from the 12 volt, but be warned, there will be the possibility of damage to the pump IF you ARE trying to KEEP this one. otherwise, there will be no issue getting the car home! cause the pump will continue to run until you cut the power.

I have never wired up a direct link to the pump from the 12 volt, otherwise I would assist you in the wire-up. but there are plenty of kats who have here!

JVD · 05-15-2007, 12:25 PM

Alright...I found a thread that I had overlooked earlier. I'm pretty sure it has to be the ground signal(or lack of) coming from the ECU to the fuel pump relay that is the problem. From what I understand when you turn the car on, the ECU will give the fuel pump relay a ground and therefore power. The relay should then switch and complete the 12V circuit that goes to the fuel pump itself. Could I just take this wire from the relay and give it a constant ground? If I wired in a switch it should act as kill switch for the pump, as well as solve my problem(assuming this is the problem), shouldn't it? I'll try this tonight...minus the switch. Haha.

*NemeGuero* · 05-15-2007, 04:44 PM

Not REEALLLY

RELAY

JVD · 05-15-2007, 05:23 PM

Quote:

Originally Posted by NemeGuero

Not REEALLLY

RELAY

Bahahaha! Totally missed that. Ya I'll try a new one. Haha.

05-15-2007, 07:25 PM

Quote:

Originally Posted by JVD

Alright...I found a thread that I had overlooked earlier. I'm pretty sure it has to be the ground signal(or lack of) coming from the ECU to the fuel pump relay that is the problem. From what I understand when you turn the car on, the ECU will give the fuel pump relay a ground and therefore power. The relay should then switch and complete the 12V circuit that goes to the fuel pump itself. Could I just take this wire from the relay and give it a constant ground? If I wired in a switch it should act as kill switch for the pump, as well as solve my problem(assuming this is the problem), shouldn't it? I'll try this tonight...minus the switch. Haha.

correct, the pump already has direct 12v+ from the battery. the ecu is responsible for switching on (and off) the ground signal (12v-) which activates the pump.

you can bypass that with your own fused power source temporarily. my ecu was actually damaged (that part of the ECU got fried) but, i was able to run for atleast a year with my own switched ground circuit and the car worked fine.

JVD · 05-16-2007, 11:01 AM

Quote:

Originally Posted by ixfxi

correct, the pump already has direct 12v+ from the battery. the ecu is responsible for switching on (and off) the ground signal (12v-) which activates the pump.

you can bypass that with your own fused power source temporarily. my ecu was actually damaged (that part of the ECU got fried) but, i was able to run for atleast a year with my own switched ground circuit and the car worked fine.

... I'm a little confused by this. From what I gathered the relay should have 4 connections. +12V from ignition on one side of the coil and ECU ground signal on the other. Then you have +12V from the battery and +12V out to the pump... or is it a ground output from the relay to the pump too and the + side that goes to the pump is right off of the battery? Can someone help me out?

Justin Bernstein · 05-16-2007, 11:58 AM

^^ I just did this...

The relay #5 leg is the hot wire to the pump. Just cut the #5 wire from the relay and run a new wire to the back of the car and splice that bitch into the lid on the fuel tank where the connections are. Everything else can just stay in the origional positions on the relay.

The only thing that is different is that the pump will not prime...it will just be on when key is on and off when key is off.

I have not gotten any response about the "non-priming/constant running" of the pump being bad for the pump. But that is not to say that it is not bad for it...i am just waiting for someone on here to tell me otherwise.

JVD · 05-16-2007, 01:00 PM

Quote:

Originally Posted by Justin Bernstein

^^ I just did this...

The relay #5 leg is the hot wire to the pump. Just cut the #5 wire from the relay and run a new wire to the back of the car and splice that bitch into the lid on the fuel tank where the connections are. Everything else can just stay in the origional positions on the relay.

The only thing that is different is that the pump will not prime...it will just be on when key is on and off when key is off.

I have not gotten any response about the "non-priming/constant running" of the pump being bad for the pump. But that is not to say that it is not bad for it...i am just waiting for someone on here to tell me otherwise.

So basically you're bypassing the relay, are you not? Ignition is just acting as your switch, rather than the relay triggering because of the ECU signal.

I better use my meter on the relay spot to make sure I'm getting 12V. I am getting the ground signal from the ECU because the relay clicks. That's the only way that could be happening.

I think this is about the time when I just need to figure shit out for myself.

JVD · 05-30-2007, 08:47 PM

Just as an update for anyone who finds this in a search.

I ended up fixing it once, only to have it cut out again mid-corner. So now I re-wired everything. I ran the ECU signal and 12v ignition to a universal Bosch relay and took power directly off of the battery with an inline fuse. Then I ran a new wire to the pump from the relay and grounded the pump to the chassis in the trunk.

I also installed a kill switch inline with the ECU signal. I'd recommend doing the same if you have to re-wire like I did.

Slidin240Wayz · 05-31-2007, 08:41 AM

So what was the issue?

JVD · 05-31-2007, 05:08 PM

Quote:

Originally Posted by Slidin240Wayz

So what was the issue?

Well first the pump seemed to be getting power and just not working. I got a new pump. I was rushing through the install because I was working on it in a busy parking lot. Haha. Needless to say I pinched the power wire in between the chassis and sending unit when I dropped the pump back in. I figured that out and the car fired right up.

THEN, I was driving my car and the pump just shut off. Not the same problem this time. I tested the plug back near the pump and wasn't getting power. Checked the relay and I WAS getting power there. That meant something was shorting out along the way from the relay to pump.

I decided not to waste my time and rewired completely. Now it's getting way more power and I feel a lot more confident knowing it's not just gonna cut out sometime.

05-15-2007, 10:09 AM	#1
JVD Nissanaholic! Join Date: Feb 2005 Location: Alberta, Canada Age: 36 Posts: 1,820 Trader Rating: (0) Feedback Score: 0 reviews	No power to fuel pump... need some help. Last week I took my car out and parked it for like an hour. When I tried starting it, it almost started then just died(I'm assuming there was still a little bit of fuel pressure). I turned the key to off and then back to on. Fuel pump wouldn't prime. Everything else is fine. Starter's good. All electronics come on too. It's just the fuel pump. The fuse is fine. I tried swapping it out. Fuse is getting power too. Haven't checked the relay yet. Anyone know what it could be? ECU maybe? This is on a 180sx with redtop SR btw. Happened on a really rainy day too if that matters at all. Forgot to mention i tried another pump too. Realized it's just not getting power.

05-15-2007, 10:35 AM	#4
NemeGuero No more nissan. Join Date: Jan 2003 Location: RAIN, Washington. Age: 40 Posts: 8,132 Trader Rating: (10) Rides Gallery: NemeGuero Feedback Score: 10 reviews	Rrreeeelllaaayyyy __________________

05-15-2007, 10:42 AM	#6
NI_YON_Zenki Zilvia Addict Join Date: Mar 2004 Location: Riverside, California Posts: 885 Trader Rating: (2) Feedback Score: 2 reviews	It may not be the relay, if the pump doesn't prime, then it could just be the pump itself, burned out from to much work. if this is a stock unit on an SR, there will be issues, the boost may be set at a higher level, the consistency of driving, strong or at ease, it depends on multiple factors. The relay however may have a burned prong, check that out, make sure you check ALL details before dealing with the obvious, because there just maybe a lurking problem that caused this, maybe not. __________________ "GHOST"

05-15-2007, 11:13 AM	#9
NI_YON_Zenki Zilvia Addict Join Date: Mar 2004 Location: Riverside, California Posts: 885 Trader Rating: (2) Feedback Score: 2 reviews	POWA! lol I think I'm going to just give the new pump direct power so I can get it home at least. It's parked somewhere still. What should I pull power from? ____Pull it from the 12 volt, but be warned, there will be the possibility of damage to the pump IF you ARE trying to KEEP this one. otherwise, there will be no issue getting the car home! cause the pump will continue to run until you cut the power. I have never wired up a direct link to the pump from the 12 volt, otherwise I would assist you in the wire-up. but there are plenty of kats who have here! __________________ "GHOST"

05-15-2007, 04:44 PM	#11
NemeGuero No more nissan. Join Date: Jan 2003 Location: RAIN, Washington. Age: 40 Posts: 8,132 Trader Rating: (10) Rides Gallery: NemeGuero Feedback Score: 10 reviews	Not REEALLLY RELAY __________________

05-15-2007, 10:13 AM	#2
slider2828 Post Whore! Join Date: Oct 2004 Location: San Francisco, CA Posts: 6,040 Trader Rating: (13) Feedback Score: 13 reviews	Just check the wires if there is power going there. You can do that by just taking the cover off the pump and test the leads at the top. But sounds like your fuel pump died. Is it new? Do you have a hatch leak? Might want to take a look at that.

05-15-2007, 10:22 AM	#3
'90RPS13 BANNED Join Date: Jan 2006 Location: NC Age: 38 Posts: 2,839 Trader Rating: (0) Feedback Score: 0 reviews	I know its simple, blown fuse?

05-15-2007, 10:37 AM	#5
NI_YON_Zenki Zilvia Addict Join Date: Mar 2004 Location: Riverside, California Posts: 885 Trader Rating: (2) Feedback Score: 2 reviews	sounds like the pump is done, if you have yet to direct power to it, then try-it, nothing to really be worried about, this gives you the opportunity to work with some new components on the street. but make sure all is relatively fine with the components associated with the ignition and fuel. I burned out my rear harness, don't ask me how, I till this day am trying to comprehend JUST how it happened, but I am working with all new wiring, so I feel good for the future. new components are installed and even newer measures will be taken. Best Regards. __________________ "GHOST"

05-15-2007, 12:25 PM	#10
JVD Nissanaholic! Join Date: Feb 2005 Location: Alberta, Canada Age: 36 Posts: 1,820 Trader Rating: (0) Feedback Score: 0 reviews	Alright...I found a thread that I had overlooked earlier. I'm pretty sure it has to be the ground signal(or lack of) coming from the ECU to the fuel pump relay that is the problem. From what I understand when you turn the car on, the ECU will give the fuel pump relay a ground and therefore power. The relay should then switch and complete the 12V circuit that goes to the fuel pump itself. Could I just take this wire from the relay and give it a constant ground? If I wired in a switch it should act as kill switch for the pump, as well as solve my problem(assuming this is the problem), shouldn't it? I'll try this tonight...minus the switch. Haha.

05-16-2007, 11:58 AM	#15
Justin Bernstein Zilvia Member Join Date: Feb 2007 Location: wherever Age: 41 Posts: 171 Trader Rating: (0) Feedback Score: 0 reviews	^^ I just did this... The relay #5 leg is the hot wire to the pump. Just cut the #5 wire from the relay and run a new wire to the back of the car and splice that bitch into the lid on the fuel tank where the connections are. Everything else can just stay in the origional positions on the relay. The only thing that is different is that the pump will not prime...it will just be on when key is on and off when key is off. I have not gotten any response about the "non-priming/constant running" of the pump being bad for the pump. But that is not to say that it is not bad for it...i am just waiting for someone on here to tell me otherwise.

05-30-2007, 08:47 PM	#17
JVD Nissanaholic! Join Date: Feb 2005 Location: Alberta, Canada Age: 36 Posts: 1,820 Trader Rating: (0) Feedback Score: 0 reviews	Just as an update for anyone who finds this in a search. I ended up fixing it once, only to have it cut out again mid-corner. So now I re-wired everything. I ran the ECU signal and 12v ignition to a universal Bosch relay and took power directly off of the battery with an inline fuse. Then I ran a new wire to the pump from the relay and grounded the pump to the chassis in the trunk. I also installed a kill switch inline with the ECU signal. I'd recommend doing the same if you have to re-wire like I did.

05-31-2007, 08:41 AM	#18
Slidin240Wayz Post Whore! Join Date: Jan 2005 Location: Everywhere Age: 40 Posts: 5,427 Trader Rating: (9) Feedback Score: 9 reviews	So what was the issue? __________________ Support Zilvia by purchasing a sticker!