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rb20det to rb25det wiring convertion help needed

theo6902
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theo6902 Rookie

theo6902

Posted
Posted

i recently( like two months ago and still havent figured it out) swapped out my blown rb20det with an rb25det in my r32 gtst. the only thing i have left is the wiring convertion. but im not exactly an autoelectrian, so i dont know exactly what to do. plus... i dont want to screw it up.

so if anyone has step by step wiring swap info or perhaps a manual or how to get a hold of a manual... IT WOULD BE GREATLY APPRECIATED

i have an rb25det wiring harness and automatic ECU.

p.s. will pay for manual or detailed info if needed. thanx

blind_elk Grand Master

blind_elk

Posted
Posted

AFAIK, they both have the same pinouts on the ECU. So the looms should be the same, and the RB25 ECU will plug straight in where the RB20 ECU came out.

Only problem will come if you fitted a RB25DET with VVT.

There is an Engine Manual available from www.jpnz.co.nz that has info on the R32 engines. As I said, I think the RB25s are the same (certainly all the RB26s will be the same across the R32 - R34 range, and most of the RB20 pinouts are the same as the equivalent RB26 pinouts).

theo6902 Rookie

theo6902

Posted
  • Author
Posted

thanks for the info. but i was hoping to find somting more specific. i have both the rb20det and the rb25det ecu pin outs and manuals. im hoping to find an actual swap manual or details on exactly what connetions to switch. like i said i dont want to f*ck it up.

BH_SLO32 Proficient

BH_SLO32

Posted
Posted

Hi,

I have just finished integrating the main R32 body plugs into a series 1.5 R33 automatic loom to make it 'plug and play' for my R32. I will not however, be running an automatic. It is my intention to produce a guide (with photos) to assist others such as yourself however this is a little down the track yet as I need to get the motor running in my R32 first (and thereby verify the arrangement) before I go publishing such data.

Although the ECU pinouts are ALMOST the same as the R32, the wiring loom is somewhat different. The R32 gets its main power feeds for the injectors, coil, ECCS relay and ECU ignition and battery power signals from the grey plug in the engine bay near the power steering reservoir. On the other hand, the R33 gets the main power feeds from the plug inside the car. So its not straight 'plug and play'. Furthermore, judging by the wiring diagrams I anticipate the R33 series 2 loom to be slightly different to the series 1. Mine is as per the series 1 arrangement.

The R32 has a separate power feed for the injectors and coil whereas the R33 loom utilises a common feed for both. After some thoughtful deliberation I decided to set the power feed arrangement up as per the R32 setup thereby not inadvertantly overloading any particular power circuit.

Do you intend running an auto or manual? What series is your motor? If I manage to find some time I can probably put together a rough guide which may be of some help to you. I would prefer to test mine first but the engine conversion may not be ready for probably 3 or 4 weeks (still waiting on engine or gearbox parts to arrive from suppliers).

I am not an autoelectrician but I am a mechanical engineer and I have a reasonable handle on 12V systems with plenty of hours experience wiring up factory ecu's (FJ20 in bluebird, RB20 in R31), car immobilisers/security system, sound systems etc.

I would offer to convert your loom for you but because you are in the UK it could be a bit difficult. If you would like further assistance let me know.

Hope this helps, Ben

  • 2 weeks later...
theo6902 Rookie

theo6902

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Posted

BH_SLO32,

sorry for not repling soon. i have been away fom my computer. i,ll be running an aoyumatic and i think my eng. i series 2. but not sure. i also have both series wiring looms. so i definately dont have a shortage of wiring. A rough guide would be great if you can put it together. in what little free time i have i keep looking over and comparing the wiring and diagrams, and im not getting very far.

The only thing keeping me from running this engine is this wiring swap. if you could please keep me up to date with your progress. and if figure anything out or come across anything i'll definately let you know aswell.

thanks, andrew

BH_SLO32 Proficient

BH_SLO32

Posted
Posted

Andrew,

I'm a little short on time at the moment as I'm preparing to do the engine and gearbox swap this weekend. Provided Murphy doesn't try and get to involved in the events of the weekend, the motor should be ready to fire by Sunday evening. I don't anticipate getting the gearbox mount modified this weekend, but the motor and gearbox should be at least sitting in place.

If I get some time next week (or even this week) I'll get started on a rough guide. I assume you have a multimeter and can solder reasonably well. Are you running the R32 or R33 automatic gearbox? I have the wiring diagram for the R32 auto ecu but not the R33. Judging by the engine manual for the R33, the main outputs from the engine ecu are similar to the R32. Without looking at the detail, it may be easier to run the R32 auto but will need to confirm.

I'll post another reply next week to let you know where I'm at.

Cheers,

Ben

theo6902 Rookie

theo6902

Posted
  • Author
Posted

ben,

i'll be running an R32 auto gear box. And from what i heard it should do alright as long as i dont push it past 300 hp for now. i have both the r32 and r33 ecu pinouts but not the full wiring diagrams. and between myself and my friend who is an aircraft electrian we got the whole connecting and checking the wiring thing handled.

thanks againg for your input.

Andrew

BH_SLO32 Proficient

BH_SLO32

Posted
Posted

Andrew,

An update as promised. Took the old motor out Sat and the new motor went in yesterday and I've been busy today hooking things up. Started the old girl this evening and she idled beutifully. Thats as far as I managed to get before giving it away for the night.

I haven't modified the mount for the RB25 gearbox yet and I have a couple of days to wait until I get my tailshaft back following modifications to accept an RB25 yoke. Hopefully I should get it back on the road next weekend.

I'll provide another update when its back on the road.

Cheers,

Ben

  • 3 years later...
BigC1988 Enthusiast

BigC1988

Posted
Posted

I just got my RB25DET (series 2) and I was hoping you could help me with some questions.

My Skyline is non turbo so it will be a big step with the RB25.

Now then, my first question is about the gearbox mounts, I hear they aren't the same and I will also have problems with the speedo meter. What do you know about this? Can I use the Xmember of the R33 ??

The second is about the harness, everyone that has ever swapped an engine told me that the harness is the most difficult part of the swap. Do you have the diagram of the R32 and the R33 (still can't find it for the R32) and some pointers on how this is done??

Hope to get a reply from you soon

Carlos Rudolph

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