Need Help with Dash Harness

[420_240]

I've tried getting help from nico and it seems no one can help me out. Haven't tried posting over here so i figured i'd give it a shot! Bring you guys up to date, I'm currently finishing up my swap of an rb25det into my 95 s14 SE. The only thing holding me back from getting it running is a fuel pump issue. There is no power going to my fuel pump! I tracked the culprit down, by starting from the fuel pump.. following the wires from the plugs ontop of the pump... these wires cross over the top of the wheelwell (next to the passengerside strut mount)... down the back passenger seat... underneath the carpeting and the harness finally stops right next to the ecu. At the end of this harness is a plug... This plug is supposed to connect to the dash harness and continue to the fusebox and fuel pump relay. Unfortunately i cannot find the plug from the dash harness, therefore, i have no power.

[s14 blacktop]

As soon as I get home I'll let you know wich wire it is? right now I cant remember what color it was?]

I know that from the fuel pump to the driverside connector its black and yellow wire and I THINK It might be blue and pink or black and pink at the F3 or is it F2 connector again not shure!

like I said when I get home I'll let you know.

[420_240]

Here's a diagram of the tail harness - body harness from the fuel pump to the picture of the plug i have posted above...

[420_240]

s14 blacktop: i'm not missing a wire... i'm missing a whole PLUG... i need to know what the plug from the dash harness looks like that goes to the plug pictured above..... right now i have my dash torn almost all the way off... heater core is half assed removed.... i can see the dash harness pretty good... i cannot see any plug that branches off the main dash harness that would fit this body plug (picture above).... maybe someone can post a pic of theirs... help me out fellas i'm dieing to get this finished

[Dream240]

Isn't there a diagram like the one you posted for the dash harness? Let me look for it and I'll let you know. now where's that factory manual.....

[s14 blacktop]

Let me know what all you need and when I get home I'll look at my 95 ( I already have my dash off) and I'll tell you what goes where.

[Dream240]

here you go. the fuel relay is the M4 plug.

Hope this helps.

[projectRDM]

You're on the wrong side of the car. That plug you're picturing looks to be the ABS plug. The only other harness that runs down the passenger side is the EVAP canister harness, the small six pin plug in that pic. The tail harness is not sourced from the passenger side at all.

The fuel pump wiring runs through the subharness down the driver side of the car, to the fuel pump relay that's mounted in the driver kick panel, below the fusebox. The signal and feed wires run from the ECU through the F3 connector into the dash harness, across the dash and through the SMJ, down to the relay and back towards the car.

You should have a black/pink and black/yellow at the F3 connector, those are the two wires you need. There's no need to go anywhere else.

[420_240]

s14 blacktop: I need a picture of the connection from the body harness to the dash harness (the plug i have pictured... to the plug i'm missing) i think (not for sure) it's supposed to clip onto the bracket that holds the ecu in place.
Dream240: Thank you for the diagram... i have the same one but i ran out file space to post it since i have posted the actual picture of my plug and the diagram of the body harness....
I believe the plug that i'm missing is either M63, M64, or M65...

I have my f3 plug... and i have the engine harness plug that connects to the f3 plug... that's all ok... i have my ignition relays, my ground, my efi plug... i just cannot find the damn dash harness plug that powers the stupid fuel pump... help me out please i'm begging!!!

[Dream240]

Forgot to mention mine is for a 96' but it should be the same.

Just wondering why the diagram I posted shows the fuel pump relay on the driver's side as M4....hmmmm what does yours have for that same plug?

That is the one you're looking for right? Fuel pump relay?

[420_240]

You're on the wrong side of the car. That plug you're picturing looks to be the ABS plug. The only other harness that runs down the passenger side is the EVAP canister harness, the small six pin plug in that pic. The tail harness is not sourced from the passenger side at all.

The fuel pump wiring runs through the subharness down the driver side of the car, to the fuel pump relay that's mounted in the driver kick panel, below the fusebox. The signal and feed wires run from the ECU through the F3 connector into the dash harness, across the dash and through the SMJ, down to the relay and back towards the car.

You should have a black/pink and black/yellow at the F3 connector, those are the two wires you need. There's no need to go anywhere else.

R240NA: So this plug has NOTHING to do with power to my fuel pump???? When i had everything plugged up (efi, f3, ign. relays, ground) on the passenger side i had dash lights, blinkers, ect. but when i turned the Key to "on" the fuel pump would never prime... i've checked the fuse and it's good... I believed it was that harness in my picture above because i opened the trunk and pulled up the carpeting... traced the wires from the fuel pump plug... down the trunk... up the passengerside wheel well... across the strut to another plug. then this plug lead down the pass. back seat under the carpet and up to the plug pictured above.

[420_240]

Forgot to mention mine is for a 96' but it should be the same.

Just wondering why the diagram I posted shows the fuel pump relay on the driver's side as M4....hmmmm what does yours have for that same plug?

That is the one you're looking for right? Fuel pump relay?

Nah i'm not looking for the relay... and now from the news that R240NA has brought me... i don't know what the hell i'm looking for... i was looking for a plug to connect to the plug i have pictured above... should have branched off somewhere around the f3 plug but i cannot find anything...

[Dream240]

Ahhh...here's the problem, you're trying to mate up your S14 tail and body wiring harnesses to the RB25 dash harness right? Okay, I get it. The reason you're looking on the USDM passenger side is because that's where the RB25 driver's side is. Basically you need to extend the RB25 wires across to the USDM driver's side and connect to the M4 plug.

don't ask why Nissan moves the fuel wires from the tank, down the passenger side, and the across the floor boards to the driver's side. I'm guessing it's because of the fuel pump fuse in the driver's side fuse box. Here's some more pics of the 240SX wiring diagrams.

Seems to me like you need the RB25 wiring diagrams from a FSM. Anyone got those? Cause I don't sorry.

[420_240]

lol Dream240... nah man, the only harness that has anything to do with my rb25 is my engine harness and that was all done by Mckinney motorsports.... the dash harness, body harness, tail harness are all still 95 s14 240sx...
what i did not know... is that the wiring from the fuel pump goes down the pass. side then across the floor boards to the fuse box...
I thought it went all the way across the pass side then up to the dash harness via the plug i'm missing....
So this is correct about the power to fuel pump... down passenger back seat across floorboards to fuse box, then through dash harness to f3 plug, then from f3 to ecu?

[s14 blacktop]

well now that you have this figured out it could only be one thing mckinney possibly misplaced one of the wires or your fuel relay blew, I ment to ask you did you hear any clicking of the fuel relays while you were trying to start the car?

Oh and do you still need the pic you asked for?

[Dream240]

lol Dream240... nah man, the only harness that has anything to do with my rb25 is my engine harness and that was all done by Mckinney motorsports.... the dash harness, body harness, tail harness are all still 95 s14 240sx...
what i did not know... is that the wiring from the fuel pump goes down the pass. side then across the floor boards to the fuse box...
I thought it went all the way across the pass side then up to the dash harness via the plug i'm missing....
So this is correct about the power to fuel pump... down passenger back seat across floorboards to fuse box, then through dash harness to f3 plug, then from f3 to ecu?

Yeah that seems to be correct. I get what you're saying after I looked at the diagrams some more. That's the other thing was wondering, which harnesses were still stock. So do you have your answer? Sorry I couldn't be of more help.

[420_240]

well now that you have this figured out it could only be one thing mckinney possibly misplaced one of the wires or your fuel relay blew, I ment to ask you did you hear any clicking of the fuel relays while you were trying to start the car?

Oh and do you still need the pic you asked for?

I haven't checked the relay yet i've still got to do that... I've been talking to Jon Powell a lot on this subject and he's requested that i check continuity between the relay and ecu... i didn't have a multimeter until about 10mins. ago when i went to autozone and bought one. I did hear a clicking noise when i was messing with my f3 plug but it sounded more like it was coming from the ecu than the driverside of the car.
Yeah man please still send a pic... i'd still like to see where this plug goes...
I called mckinney and asked them about this... mack seemed pretty pissed when i said, "i'm missing a plug"... but he explained to me that there is no power source to the fuel pump from the engine harness... there is no plug that goes to the "homeless body plug" on the engine harness either.

I know the pump is good cause i've hooked it up to a car chager and it started right up....

So now that i've got this multimeter (have no idea how to use this thing)... what should i be checking?

**Another thing... my taillights work and i believe my floater works inside my fuel tank... i've unplugged the plug that goes to that and my fuel gauge needle dropped... when i plugged it back in it went back up... No clue?

[420_240]

i found (what i believe to be) the fuel pump relay... only relay on the driverside that has black/pink and black/yellow wires.... So how do i check for continuity between relay and ecu?

[projectRDM]

Alright, you're still off about a few things. The fuel pump wiring NEVER goes anywhere to the passenger side of the car, and never crosses the floorboard. It exits the tank and goes around the back of the car, past the right tailight to the left tailight, then straight up the driverside, all the way to the relay. What you're looking at in the trunk may *appear* to be the fuel pump wiring, it's not. The EVAP harness runs back over the passenger shock tower and mates in with the tail harness, the in-tank fuel temperature sensor lead comes out of the EVAP harness and goes into the tank, that's what you're seeing and getting confused about.

It's done like this because originally the car was RHD (Japan, 1994 model year), and everything forward of the tail harness was reversed. It made sense to run it down the the US passenger side because the relay was also on that side, along with the SMJ. By going LHD, the dash harness was flipped, so to cut down wire length from the relay to the pump, they moved the subharness to the other side (US driverside) of the car.
Again, at the F3 connector you'll have both leads that you need, unless they did the harness wrong there is no need to go anywhere else.
Check freshalloy's archives for the 1996 pinout of the F3 plug that I made, it's very clear on which pins are for the pump.
Verify continuity from the ECU, through F3, to the relay. To verify the relay is working, ground the black/pink lead, you should hear it click on and fire the pump. If all that is good, then the ECU driver is bad.

[420_240]

Verify continuity from the ECU, through F3, to the relay. To verify the relay is working, ground the black/pink lead, you should hear it click on and fire the pump. If all that is good, then the ECU driver is bad.
How do i verify continuity between the ecu and relay? I just got a multimeter and have never used one before, also... if i clip the black/pink wire... which piece do i use to ground?... the one that is plugged into the f3 harness or the one leading to the ecu... or the piece that leads to the dash harness to the relay?

[420_240]

by the way fellas i really do appreciate the quick help... i'm glad to see this is a really supportive forum... forgive my ignorance if my questions have been somewhat amateur... I am still a learning grasshoppa :bow:

[420_240]

This is what i found when i went to freshalloy under the archives keyword, "1996"
>1-black/red, ignition lead to injectors, coil
>2-
>3-blue/red, rear defogger/electrical load signal
>4-pink, washer switch
>5-light green, ignition lead to wiper motor
>6-light green/black, wiper motor high
>7-light green/red, wiper motor low
>8-brown, wiper off/int switch
>9-
>10-black/yellow, fuel pump signal to F23, IACV-IAA
>11-black/pink, fuel pump relay signal
>12-orange, headlamp diode
>13-
>14-
>15-purple/white, P/S oil pressure switch
>16-yellow/black, AC switch
>17-red, battery lead to ECCS relay
>18-brown, igniton lead to O2 sensors, EGRC solenoid, EVAP purge/vent
>solenoids, IACV, TPS
>19-
>20-red, GST port
>21-yellow, GST port
>22-green, CONSULT port
>23-green/white, CONSULT port
>24-yellow/green, VSS signal
>25-orange/blue, cooling fan high signal
>26-yellow/red, tachometer
>27-blue/yellow, wiper intermittent switch
>28-yellow, temp gauge sending wire
>29-black/white, ambient air temperature switch
>30-orange, MIL lamp
>31-blue/white, ASCD actuator power
>32-blue, ASCD air valve
>33-yellow/blue, 5th gear position switch
>34-orange, start signal
>35-
>36-
>37-orange/blue, recirculation relay
>38-green/black, CONSULT port
>39-
>40-green/orange, neutral position switch
>41-blue/green, cooling fan low signal
>42-purple, wiper variable intermittent switch
>43-black/pink, triple pressure switch signal
>44-blue/red, IACV-FICD signal
>45-orange/black, triple pressure switch line
>46-ornage/blue, AC thermo control amp
>47-green/yellow, ASCD release valve
>48-blue/black, ASCD vacuum motor
I know there are 2 black/pink wires... 1 for fuel pump... 1 for triple pressure switch signal....
I also need to find the black/yellow wire for the fuel pump... since this wire is 10 and the black/pink wire i need is 11... should i just look for the black/pink wire next to a black/yellow wire?

[projectRDM]

Correct, pins 10 and 11.

To verify continuity, set the multimeter to the proper setting, touch one lead to the ECU plug and the other across the dash to the relay, on each wire. This will tell you if the lead is good from the ECU, through F3, to the relay. Check both wires.

Now, take the black/pink, do not cut it, just run a small piece of wire into the relay terminal and ground the other side, with the key on, you should hear/feel it click.

[420_240]

I've been messing around with the multimeter (never used one before) and just got comfortable using one. Unfortunately my battery is pretty much dead... so i'm trying to charge it over night...
I did a little research on how to use these on cars and i read that you're supposed to disconnect the neg. battery terminal, is this correct??
Also, R240NA, thank you for your information it has been most helpful, when you said, "to verify continuity, set the multimeter to the proper setting, touch one lead to the ECU plug and the other across the dash to the relay, on each wire." Which pin do i need to touch on the ECU plug? Or does this matter since it's just checking if there's power from ecu->f3->relay?
Also you said, "check both wires." I'm confused... are you referring to the black/pink and black/yellow on the dash harness f3 plug?
I should have more questions in the morning when my battery is fully charged and i can get a proper reading out of harness.... again thanx so much for your time it's really appreciated.

[s14 blacktop]

Sorry for the wait man but my net at home is down so I didnt see your reply until today, you have the same problem I had, it turns out that one of my wires was hooked up to the wrong source and thats why it didnt turn on, in my case it was just bad rewiring, it turned out that the black and yellow IACV-IAA wasnt in the correct pin its easy to confuse this with all the other IACV pins just check this wire and find out which wire is the IACVV-IAA on the sky engine and it should work...in my case thats what it was with my SR..

[projectRDM]

I did a little research on how to use these on cars and i read that you're supposed to disconnect the neg. battery terminal, is this correct??
Also, R240NA, thank you for your information it has been most helpful, when you said, "to verify continuity, set the multimeter to the proper setting, touch one lead to the ECU plug and the other across the dash to the relay, on each wire." Which pin do i need to touch on the ECU plug? Or does this matter since it's just checking if there's power from ecu->f3->relay?
Also you said, "check both wires." I'm confused... are you referring to the black/pink and black/yellow on the dash harness f3 plug?

No need to disconnect the battery, you can, but either way you're only checking continuity, doesn't matter.
Check the corresponding black/yellow and black/pink at the ECU all the way to the relay, there won't be power unless it's running (black/yellow) or a ground signal (black/pink), you're just mainly verifying that they're connected right. The feeds go from the ECU -> F3 -> dash harness across the dash -> relay.
Check continuity for both wires, from ECU to the relay.

[420_240]

I have no black/pink or black/yellow on my f3 ->ecu (engine harness)...
however, I do have a black/pink and black/yellow on my f3->relay (dash harness)... here's some pictures to help explain...

As you can see in the first "picture 456" I have the black/yellow and black/pink wires circled and labled... this is the plug that is attatched to the dash harness
In "picture 455" I have cirlced and labled the pins where black/yellow and black/pink should be... but instead i only have that light blue wire

I'm ready to pay a shop to finish my car for me cause i need to have it running by the time school starts... anyone know a place close to western KY????

[s14 blacktop]

its the dash harness that were talking about, did you try what I told you earlier?
do you have a pinout of your skyline engine? I could find the wire for you that way!

[projectRDM]

I'm in Atlanta, not too far, but I couldn't make it up until after the holidays.

I'm confused as to how they wired the engine harness in, it looks like they used the RB F3 plug, but there should be a lot of other stuff tied in. I've got a friend local with a 25, if I can get into his car this weekend I'll check what the differences are. In the meantime, get a pinout of the ECU and trace the fuel pump wiring out and see where they end up. I've never known a Nissan engine harness to not have those wires, in those exact colors.

[420_240]

I tried checking for continuity yesterday... Didn't get anything... Then again i don't really know if i was doing this shit right. Had one lead in pin 18 of the efi (blue plug) and the other lead in the fuel pump relay at the black/pink wire...Nothing.
Had the multimeter set on Ohms and didn't get anything... I don't know what to do

Anyone know any reputable RB/SR/Nissan Specialists in the Western KY area??? I'm 2 hours from Nashville and I'm 2 hours from St. Louis

[projectRDM]

Wrong setting, you want continuity, not resistance. Depending on the meter, it will have a squigly line, set it there and touch the leads together, if there's a beep then you're on the right setting.

[420_240]

Damnit i don't know if this stupid multimeter is capable of checking for continuity.... I need to know if power can go from the ecu -> f3 -> relay