Need some help with RB25 swap

[bkos90]

I just recently swapped a RB25det S2 into an 89 S13. This swap has been the biggest pain in the a** since i got all the wiring diagrams and write ups that are for the r33 rb25det. But for some apparent reason i got my S2 motor with the r34 rb25det ecu and the wiring harness. So i basically did the wiring by looking at the write up and then do it wire by wire from the r33 ecu to the r34 ecu, for example the blk/red wire from KA to ecu pin 53. so i would go and look at the r33 ecu pin out and see what it is and then look at the r34 pin out, match them up and connect the wires but its still not starting. Has anyone done anything like this?

My main question is: I notices that im missing the ignition relay on the RB wiring harness and was wondering if its needed for the engine to start, since there is already an ignition relay on the s13 at the right fender?

Here is a pic of the relay that im talking about

And this is how my ecu looks like

[Funktown240]

There should have been two relays close to the ECU pins. . .at least there were on my S1 RB25.

[platez808]

series 2 rb25det harnesses only have the eccs relay. The series 2 motors have the ignitors built into the coilpacks, getting rid of the need to have an ignitor chip (which is located on the coilpack cover on a series 1 motor) and the ignitor relay that you are looking for.

On another note.. if that really is an r34 rb25det neo, then that (grey, a bajillion pins in a bajillion different rows) looks way different than r33 rb25dets ecu (blue, two even rows of pins) and i'd be willing to bet that it wont work at all. best bet is to get a true r33 rb25det ecu, either series 1 or 2 (which according to my experiences are interchangeable.) good luck

[bkos90]

series 2 rb25det harnesses only have the eccs relay. The series 2 motors have the ignitors built into the coilpacks, getting rid of the need to have an ignitor chip (which is located on the coilpack cover on a series 1 motor) and the ignitor relay that you are looking for.

On another note.. if that really is an r34 rb25det neo, then that (grey, a bajillion pins in a bajillion different rows) looks way different than r33 rb25dets ecu (blue, two even rows of pins) and i'd be willing to bet that it wont work at all. best bet is to get a true r33 rb25det ecu, either series 1 or 2 (which according to my experiences are interchangeable.) good luck

Thanks a lot for the help

And you are saying that it wont work at all? i have everything wired up but it doesn't start so my guess is its because im missing the relays.

I also contacted the shop i got the engine from and they told me that that is the way they got it from japan. He said that they dont change anything, the way they get it is the way it is, so if its like that then it was running like that before. I honestly dont understand how a series 2 rb25det and not even the neo ended up in an r34.

What would you suggest me to do. im kind of on a low budget and dont really have money to buy another rb25 harness and ecu. I got the motor on ebay and paid through paypal. maybe i can tell them something or make a deal with them.

I also got the harness all cut and spliced so i doubt they would want to trade it.I really dont know what to do Please help. thanks

[Coolwhip]

where are you in Florida? I'm in Orlando, and have both R33 Series 2 Harnesses and S2 ECUs in stock. Shoot me an email, should have something that would work out for your needs and budget.

As mentioned by a previous poster, blue plug = R33... Gray Plug is R34 NEO ECU and should be stickered as G8 or similar.

I'm afraid that you will be unsuccessful with repinning and running your engine on that ECU. The CAS, MAF, Injectors, TPS, AAC, O2 sensors on the R34 RB25 NEO are all different than the R33 RB25 S2.

[platez808]

What would you suggest me to do. im kind of on a low budget and dont really have money to buy another rb25 harness and ecu. I got the motor on ebay and paid through paypal. maybe i can tell them something or make a deal with them.

I also got the harness all cut and spliced so i doubt they would want to trade it.I really dont know what to do Please help. thanks

No problem at all. If I were in your shoes, I would first talk to the shop you got it from and try to work something out, but some how i dont think they'll even move a finger in your situation so i wouldnt bank on it.

Next best route is to pick up an ecu (i bought one i found in the classifieds for 80 bucks recently) or you can talk to coolwhip. From there, i would just study up on the wiring diagrams and write ups for doing the rb25 to s13 swap. If your engine is a true series 2 motor then the harness you have should work if wired correctly. Hopefully you can undo the damage already done by you trying to rewire the harness to work with the r34 ecu if thats what you did. I mean its not impossible but it might take a while to figure out (i made a hacked up harness work on my swap.) Just gotta be patient.

The easiest route would definitely be to pick up a nice untouched harness and start the wiring from scratch, but not sure if that will fit your budget (it didnt fit mine hahaha) For this step i would definitely talk to coolwhip

Good luck