Fuel Pump Wiring-from Relay to Pump question. - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Justin Bernstein · 05-01-2007, 07:53 PM

Hey guys,

95 Zenki/SR

So I installed a Walbro and it worked fine for a couple of weeks. I haven't been driving the car because I have been finishing up some things and haven't driven it on the road for awhile.

The fuel pump just stopped priming....so, I pulled it and checked the wiring, which was all good.

I pulled the pump out and hard wired it...and it works.

I checked the relay...and it works.

I then took a wire and ran it from the #5 pin on relay (to fuel pump). And ran it directly to the positive pump wire and grounded the pump...and it worked.

So, now im thinking that the hot wire from relay to pump is bad somewhere in the car...

MY QUESTION - can I simply run a wire from #5 on relay directly to the plug on top of the fuel pump assembly on top of the gas tank that goes to the fuel pump on the carrier?

This confuses me because I traced the positive wire from the pump all through the car and it meets up with a fuckin box of some type behind the carpet in the trunk ( I think ).

So would it be proper to just run a single new wire to the positive on the pump right from the relay?

Thank you in advance for any assistance that you may be able to provide on this.

-Justin

nassin31spr · 05-02-2007, 05:07 AM

The ecu sends the signal to the relay box. You probobly burned your ecu up. If you have a spare try switching it out before you take the time to wire up the pump.

Justin Bernstein · 05-02-2007, 07:32 AM

Dude thanks for your help but I already diagnosed that its not the ecu because the relay IS getting power.

The relay also closes properly.

The problem is the #5 pin wire on the relay is bad and is not getting power to the pump.

So my question is if I can just replace that hot wire from the #5 on the relay directly to the pump positive wire?

I checked it yesterday and it does power the pump properly if i do that, I just want to be sure that it will be safe, and I want to be sure the wire doesn't go through any other relays or anything before it gets to the fuel pump carrier.

MadScientist · 05-02-2007, 07:57 AM

This is your friend... http://www.240edge.com/manuals/usdm-cars.html

Peace
Drew

Z U L8R · 05-02-2007, 08:03 AM

first off...AM YISRAEL CHAI ^_^

second off, lol, the fuel pump relay wire should be black with a pink stripe and the ecu gives that wire a GROUND signal to the relay when you turn the key to igntion ON position for the first 5 seconds. then it will give that wire a solid ground signal as it sees the engine rotating via the cam angle sensor during starting and operation. the ecu gives the black/pink wire ground, the relay clicks completing the circuit, thus giving the fuel pump's positive wire the 12 volts, i believe the pumps positive wire should be black/yellow at the top on that plug that plugs into the fuel sender.

i don't know what you mean by pin 5 cause whether you're calling pin 5 something off the dash plug or the ecu, for either an s13, s14, or s15 sr20det, pin 5 has nothing to do with fuel at all.

the wire you want is BLACK with a PINK stripe. for an s13 sr20det it'd be on the brown f10 connector that runs by the battery on an s13 which corresponds with pin #104 on the s13 sr20's ecu. if you're using an s14 sr20motor/ecu it'd be pin #18 on the ecu and in that case it may be black/pink or black/yellow depending on what you have.

remove pin #5 from this scenario. wire in the correct fuel pump relay wire into your car/dash plug. if you cannot figure it out, don't fry anything and listen to another Yid. do it like this..

get a 4 leg 12volt 20 or 30 amp relay from the parts store. usually how they have it set up is leg 1 and 2 have a picture with a pubic hair inbetween them. on 1 put an ignition sourced 12volt and on 2 put the black with pink wire, now you have 2 legs left, usually it'll be 3 and 5 but in any case, it'll look like a door that if it's shut it would connect 3 to 5, but with the relay deactivated 5 should be completely dead. T off of the 12volt ignition wire that you ran to leg 1 and run that to 3 also, then for 5, run your own wire to the fuel pump's positive wire.

congratulations, you have now bipassed your stock fuel pump wiring that's all screwed up

Justin Bernstein · 05-02-2007, 08:32 AM

^^ Thanks bro ^^

When I was referring to the "#5", I meant on the relay "#5 leg" as you call it. That is indeed the hot wire to the fuel pump, this I already knew.

The relay is fine, because I already tested the "#5 leg" with a wire directly connected from that leg to the hot wire on the pump, and with the pump grounded, it works.

You said: "then for 5, run your own wire to the fuel pump's positive wire.

congratulations, you have now bipassed your stock fuel pump wiring that's all screwed up"

So what your saying is that I can just cut the #5 wire on the relay and use my own wire, run it through the car, and splice it to the TOP OF THE FUEL PUMP SENDER???

Thanks again.

Z U L8R · 05-02-2007, 08:45 AM

nachon (correct)
ken (yes)

^_^

Justin Bernstein · 05-02-2007, 06:00 PM

Yo,

So I wired it up the way that I discussed above, and now the pump works...but, it dosen't stop priming.

It just runs....and I start the car, and its all good...

But, is it bad that it dosent stop priming?

what could be the reason for that?

Z U L8R · 05-02-2007, 06:04 PM

it's not really bad for the car persay, but it doesn't sound like you're using the correct fuel pump signal (ground) wire from the ecu for the ground to activate the relay....

Justin Bernstein · 05-03-2007, 07:21 AM

Yea maybe,

But, I never touched the relay other than to replace the #5 (to fuel pump) wire.

It is still hooked up to the ECU normally, I just cut and spliced a new hot wire to pump.

I drove it for the first time in awhile yesterday and it was fine but seems like I need to adjust the fuel pressure down a bit.

But other than that its fine as long as the fuel pump can constantly run like that...prob will burn out sooner but I just dont want it to fuck up anything else...fuel rail/engine.

Does anyone know if there are any other relay type connections that the hot wire connects to after the relay but before it gets to the fuel pump?

Again, Thanks.

-J

Z U L8R · 05-03-2007, 08:20 PM

nothing inline from fp relay to fp

Justin Bernstein · 05-03-2007, 09:42 PM

hmm...well shit...

Car still works...soo im confused why it dosen't stop priming..

Before, you said i may be using the wrong wire off the relay.

If so which wire should i run to the hot side of the pump?

sunnys14 · 05-10-2007, 07:43 PM

i want to know also

Justin Bernstein · 05-11-2007, 08:21 AM

Quote:

Originally Posted by sunnys14

i want to know also

so, you did the same thing as me? and your pump wont stop priming?

whats funny is that my car runs fine with the pump wired up as I did it above.

I cant help but thinking that it cant be good for the pump to just keep priming because the factory wouldn't have wired it to stop priming after a few secs!?

Does any one else have any input??

05-02-2007, 07:57 AM	#4
MadScientist Zilvia.net Advertiser Join Date: Mar 2003 Location: NOLA Age: 48 Posts: 1,972 Trader Rating: (3) Feedback Score: 3 reviews	This is your friend... http://www.240edge.com/manuals/usdm-cars.html Peace Drew __________________ Follow on IG - KoukiTheToolBox

05-01-2007, 07:53 PM	#1
Justin Bernstein Zilvia Member Join Date: Feb 2007 Location: wherever Age: 41 Posts: 171 Trader Rating: (0) Feedback Score: 0 reviews	Fuel Pump Wiring-from Relay to Pump question. Hey guys, 95 Zenki/SR So I installed a Walbro and it worked fine for a couple of weeks. I haven't been driving the car because I have been finishing up some things and haven't driven it on the road for awhile. The fuel pump just stopped priming....so, I pulled it and checked the wiring, which was all good. I pulled the pump out and hard wired it...and it works. I checked the relay...and it works. I then took a wire and ran it from the #5 pin on relay (to fuel pump). And ran it directly to the positive pump wire and grounded the pump...and it worked. So, now im thinking that the hot wire from relay to pump is bad somewhere in the car... MY QUESTION - can I simply run a wire from #5 on relay directly to the plug on top of the fuel pump assembly on top of the gas tank that goes to the fuel pump on the carrier? This confuses me because I traced the positive wire from the pump all through the car and it meets up with a fuckin box of some type behind the carpet in the trunk ( I think ). So would it be proper to just run a single new wire to the positive on the pump right from the relay? Thank you in advance for any assistance that you may be able to provide on this. -Justin

05-02-2007, 05:07 AM	#2
nassin31spr Zilvia Junkie Join Date: Jan 2007 Location: clay town NC Age: 45 Posts: 437 Trader Rating: (7) Feedback Score: 7 reviews	The ecu sends the signal to the relay box. You probobly burned your ecu up. If you have a spare try switching it out before you take the time to wire up the pump.

05-02-2007, 07:32 AM	#3
Justin Bernstein Zilvia Member Join Date: Feb 2007 Location: wherever Age: 41 Posts: 171 Trader Rating: (0) Feedback Score: 0 reviews	Dude thanks for your help but I already diagnosed that its not the ecu because the relay IS getting power. The relay also closes properly. The problem is the #5 pin wire on the relay is bad and is not getting power to the pump. So my question is if I can just replace that hot wire from the #5 on the relay directly to the pump positive wire? I checked it yesterday and it does power the pump properly if i do that, I just want to be sure that it will be safe, and I want to be sure the wire doesn't go through any other relays or anything before it gets to the fuel pump carrier.

05-02-2007, 08:03 AM	#5
Z U L8R Zilvia FREAK! Join Date: Jan 2007 Location: Georgia Age: 43 Posts: 1,194 Trader Rating: (0) Feedback Score: 0 reviews	first off...AM YISRAEL CHAI ^_^ second off, lol, the fuel pump relay wire should be black with a pink stripe and the ecu gives that wire a GROUND signal to the relay when you turn the key to igntion ON position for the first 5 seconds. then it will give that wire a solid ground signal as it sees the engine rotating via the cam angle sensor during starting and operation. the ecu gives the black/pink wire ground, the relay clicks completing the circuit, thus giving the fuel pump's positive wire the 12 volts, i believe the pumps positive wire should be black/yellow at the top on that plug that plugs into the fuel sender. i don't know what you mean by pin 5 cause whether you're calling pin 5 something off the dash plug or the ecu, for either an s13, s14, or s15 sr20det, pin 5 has nothing to do with fuel at all. the wire you want is BLACK with a PINK stripe. for an s13 sr20det it'd be on the brown f10 connector that runs by the battery on an s13 which corresponds with pin #104 on the s13 sr20's ecu. if you're using an s14 sr20motor/ecu it'd be pin #18 on the ecu and in that case it may be black/pink or black/yellow depending on what you have. remove pin #5 from this scenario. wire in the correct fuel pump relay wire into your car/dash plug. if you cannot figure it out, don't fry anything and listen to another Yid. do it like this.. get a 4 leg 12volt 20 or 30 amp relay from the parts store. usually how they have it set up is leg 1 and 2 have a picture with a pubic hair inbetween them. on 1 put an ignition sourced 12volt and on 2 put the black with pink wire, now you have 2 legs left, usually it'll be 3 and 5 but in any case, it'll look like a door that if it's shut it would connect 3 to 5, but with the relay deactivated 5 should be completely dead. T off of the 12volt ignition wire that you ran to leg 1 and run that to 3 also, then for 5, run your own wire to the fuel pump's positive wire. congratulations, you have now bipassed your stock fuel pump wiring that's all screwed up

05-02-2007, 08:32 AM	#6
Justin Bernstein Zilvia Member Join Date: Feb 2007 Location: wherever Age: 41 Posts: 171 Trader Rating: (0) Feedback Score: 0 reviews	^^ Thanks bro ^^ When I was referring to the "#5", I meant on the relay "#5 leg" as you call it. That is indeed the hot wire to the fuel pump, this I already knew. The relay is fine, because I already tested the "#5 leg" with a wire directly connected from that leg to the hot wire on the pump, and with the pump grounded, it works. You said: "then for 5, run your own wire to the fuel pump's positive wire. congratulations, you have now bipassed your stock fuel pump wiring that's all screwed up" So what your saying is that I can just cut the #5 wire on the relay and use my own wire, run it through the car, and splice it to the TOP OF THE FUEL PUMP SENDER??? Thanks again.

05-02-2007, 08:45 AM	#7
Z U L8R Zilvia FREAK! Join Date: Jan 2007 Location: Georgia Age: 43 Posts: 1,194 Trader Rating: (0) Feedback Score: 0 reviews	nachon (correct) ken (yes) ^_^

05-02-2007, 06:00 PM	#8
Justin Bernstein Zilvia Member Join Date: Feb 2007 Location: wherever Age: 41 Posts: 171 Trader Rating: (0) Feedback Score: 0 reviews	Yo, So I wired it up the way that I discussed above, and now the pump works...but, it dosen't stop priming. It just runs....and I start the car, and its all good... But, is it bad that it dosent stop priming? what could be the reason for that?

05-02-2007, 06:04 PM	#9
Z U L8R Zilvia FREAK! Join Date: Jan 2007 Location: Georgia Age: 43 Posts: 1,194 Trader Rating: (0) Feedback Score: 0 reviews	it's not really bad for the car persay, but it doesn't sound like you're using the correct fuel pump signal (ground) wire from the ecu for the ground to activate the relay....

05-03-2007, 07:21 AM	#10
Justin Bernstein Zilvia Member Join Date: Feb 2007 Location: wherever Age: 41 Posts: 171 Trader Rating: (0) Feedback Score: 0 reviews	Yea maybe, But, I never touched the relay other than to replace the #5 (to fuel pump) wire. It is still hooked up to the ECU normally, I just cut and spliced a new hot wire to pump. I drove it for the first time in awhile yesterday and it was fine but seems like I need to adjust the fuel pressure down a bit. But other than that its fine as long as the fuel pump can constantly run like that...prob will burn out sooner but I just dont want it to fuck up anything else...fuel rail/engine. Does anyone know if there are any other relay type connections that the hot wire connects to after the relay but before it gets to the fuel pump? Again, Thanks. -J

05-03-2007, 08:20 PM	#11
Z U L8R Zilvia FREAK! Join Date: Jan 2007 Location: Georgia Age: 43 Posts: 1,194 Trader Rating: (0) Feedback Score: 0 reviews	nothing inline from fp relay to fp

05-03-2007, 09:42 PM	#12
Justin Bernstein Zilvia Member Join Date: Feb 2007 Location: wherever Age: 41 Posts: 171 Trader Rating: (0) Feedback Score: 0 reviews	hmm...well shit... Car still works...soo im confused why it dosen't stop priming.. Before, you said i may be using the wrong wire off the relay. If so which wire should i run to the hot side of the pump?

05-10-2007, 07:43 PM	#13
sunnys14 Zilvia FREAK! Join Date: Mar 2006 Location: a land far far away... Posts: 1,549 Trader Rating: (19) Feedback Score: 19 reviews	i want to know also