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Rb25 Wiring Gurus Needed Please


Paulpen
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Im quite a lurker, reader and searcher but less of a poster but hoping that wont matter :

Long story but here goes

18 months ago I did a RB25 (series 1) conversion into my S13. It was my daily at the time and I needed it to work so got someone to do it that was supposedly an expert at it.

I did the swap and it didnt start. No power to injectors or coils so I got it running.

Skip foward 18 months. Im now breaking my S13 and building a Onevia that the RB is going in. I cleaned all the unwanted wires from the car loom and then get to the engine one. Untape it etc and O.M.F.G its a mess.

Ive already sorted out the bodged pins in connectors but have a few questions that I cant really sort without looking at another loom or someone knowing it :bawling:

So here is what I know :

The R33 harness connects to the dash harness at one point so mine was repinned to fit my dash harness. Currently I have 4 wires in it which ive traced as follows :

Yellow/red - splits into two wires and goes to the tacho readout wire in the bay and the ecu

Yellow/green - to the ecu

Blue/black - Temperature gauge

Orange -> grey/red - ecu

And thats all I have in that connector as per pic

DSC00124.jpg

Im guessing this is the R33 version of what im using (but with more wires)

DSC00119.jpg

strange thing is that I have 3 wires going into this from the engine loom so they go nowhere !

Ive traced them so here goes

Black - goes to a purple inlent manifold plug - think its AAC (air con idle up) ?

Light blue - Goes to a gray connector with an orange insert, not sure where but possibly front of inlet area. Heres a pic or two as im crap with words

DSC00120.jpg

DSC00121.jpg

Blue/white - splits off into 4 wires after about a foot. These then go to a coil pack plug, what I think is the VVT (first pic below), the oxygen sensor and what I think is the boost solenoid (second pic below).

DSC00122.jpg

DSC00123.jpg.

If you are still reading then thankyou :)

The thing I find strange is that the car seemed to run fine on stock parts but did overfuel a bit and pulled 285ish on standard boost.

Help very much welcome :(

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Looks like this "expert" made a real meal of the loom.

The R33 harness connects to the dash harness at one point so mine was repinned to fit my dash harness. Currently I have 4 wires in it which ive traced as follows :

Yellow/red - splits into two wires and goes to the tacho readout wire in the bay and the ecu

Yellow/green - to the ecu

Blue/black - Temperature gauge

Orange -> grey/red - ecu

Yellow/Green is most likely pin 53 (speedo signal)

Im guessing this is the R33 version of what im using (but with more wires)

strange thing is that I have 3 wires going into this from the engine loom so they go nowhere !

Ive traced them so here goes

Black - goes to a purple inlent manifold plug - think its AAC (air con idle up) ?

Light blue - Goes to a gray connector with an orange insert, not sure where but possibly front of inlet area. Heres a pic or two as im crap with words

Blue/white - splits off into 4 wires after about a foot. These then go to a coil pack plug, what I think is the VVT (first pic below), the oxygen sensor and what I think is the boost solenoid (second pic below).

DSC00122.jpg

DSC00123.jpg.

Black is earth for the FICD solenoid (increases idle when AC is switched on).

Light blue is the power feed to the air regulator. This plug has the air regulator power and return and the knock sensor wires.

Blue/white is the power feed to the O2 heater, VCT, AAC and boost solenoid.

Hope that helps.

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Spot on chaps :)

Think im going to have to trace everything from the ecu and check it against the pinouts I have saved :)

From what you guys have said so far I think I can determin the following then !

The main relays must be wrong in some way as they switch without the OS2, idle control etc :P

Id also guess I dont need the speedo signal but ill wire it in correctly seeing as I need to sort everything anyways

I dont have air con but ill wire the FICD anyways for future use maybe

Im sure ill have a load more questions in a few hours :D

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Traced every wire from the ecu connector to its end tonight and here is what ive now got. I used the following guide but not sure if its correct or my loom is missing alot of things :S

RB25Terminals.jpg

I made a table of what ive got and where it is and uploaded it here as cant seem to get the table to look correct any other way :D

MEGAUPLOAD - The leading online storage and file delivery service

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To a point yes - but how much time are you going to spend on it?

Looms are cheap, in UK money especially :D

At the end of the day if you repair this one and so on, you better hope you get it 100% right. Later down the track all sorts of niggles can come up with butchered looms.

I've been through it myself, was easier and faster in the end to just suck it and buy a new loom. Not worth the drama's sometimes as Nissan & electrics/looms from all my past cars and friends... are not all that friendly at times

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To a point yes - but how much time are you going to spend on it?

Looms are cheap, in UK money especially :P

At the end of the day if you repair this one and so on, you better hope you get it 100% right. Later down the track all sorts of niggles can come up with butchered looms.

I've been through it myself, was easier and faster in the end to just suck it and buy a new loom. Not worth the drama's sometimes as Nissan & electrics/looms from all my past cars and friends... are not all that friendly at times

I understand exactly what you are saying.

I think tomorrow ill see if its beyond saving and may then make the decision. IF I can get it back to standard ill be ok but thats quite a big IF at the moment ! :D

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  • 2 weeks later...

Well after alot of time and help I think ive got it all done correctly now :(

Just a question about the coil pack loom though - is it meant to have 2 earth bolt connectors ? One goes the the white plug and one comes from inside the tape going to the pack connectors ?

Coilloom.jpg

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Ideal - dont spose you know where they bolt up to ?

I know one goes on the end of the coil pack mount frame but unsure on the other ;)

pretty much anywhere will do, maybe just put it on the same place as the other one.

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