rb25 engine and trans swap work but without the tcm?

[romel]

Hii all,

 

I am doing a rb25de neo engine and transmission swap on my r34 but wanna keep the rb20de harness so i spliced and joint the transmission cables(speed sensor, park neutral switch and solenoids) where needed cause the rb20 wiring is ecm.tcm 

i already found an rb25 ecu with ecm tcm in one instead of separate cause my rb20 setup was ecm tcm. The rb25 transmission has an turbine sensor , does the turbine sensor need to be connected or can i just leave it disconnected?

 

Are there any issues that i will run into with you the setup?

[Kinkstaah]

This may not be the right place to say it, but the RB25NEO N/A is actually ecm with seperate TCM as well.

Those inputs are incorporated cleanly into the R34 GTT from memory (according to my memory of the workshop manual). In short, if you have the correct RB25NEO ecu, it won't have any provisions for transmissions. If you have the RB25NEO DET ECU, it should have them all.

... if it's an auto ECU.

[GTSBoy]

And if you don't provide all the input signals that the TCU expects, it will have a sad and throw codes and possibly (probably) limp.

[romel]

11 hours ago, Kinkstaah said:

This may not be the right place to say it, but the RB25NEO N/A is actually ecm with seperate TCM as well.

Those inputs are incorporated cleanly into the R34 GTT from memory (according to my memory of the workshop manual). In short, if you have the correct RB25NEO ecu, it won't have any provisions for transmissions. If you have the RB25NEO DET ECU, it should have them all.

... if it's an auto ECU.

The ecu i was going to connect to the setup is a 23740-0V010 ecu of a stagea that has ecm and tcm in one

[Kinkstaah]

Right, so that is the same (or very similar, I'm not sure how similar) to the GTT ECU.

I only looked at this for 15 minutes about a decade ago, but from what I remember, all of the sensors/wires/pins for the R34 N/A TCM existed on the R34 GTT main ECU. Basically the only difference between the GTT auto and GTT manual ECU was the addition of those pins, which perfectly mapped to the TCU's pins in the NA car.

This was followed by a lot of me screaming why a workshop could not have figured this out in the 3 years they had previously had the car. It's possible there's some other complication..

In my example I had a standalone transmission ECU, which I wired into following the diagrams and everything worked fine. I found other posts that people had wired the NA Autobox into the GTT ECU without issue, and after looking at the diagrams I understood why there was no obvious writeup for it. I ASSUME.

[romel]

18 hours ago, Kinkstaah said:

Right, so that is the same (or very similar, I'm not sure how similar) to the GTT ECU.

I only looked at this for 15 minutes about a decade ago, but from what I remember, all of the sensors/wires/pins for the R34 N/A TCM existed on the R34 GTT main ECU. Basically the only difference between the GTT auto and GTT manual ECU was the addition of those pins, which perfectly mapped to the TCU's pins in the NA car.

This was followed by a lot of me screaming why a workshop could not have figured this out in the 3 years they had previously had the car. It's possible there's some other complication..

In my example I had a standalone transmission ECU, which I wired into following the diagrams and everything worked fine. I found other posts that people had wired the NA Autobox into the GTT ECU without issue, and after looking at the diagrams I understood why there was no obvious writeup for it. I ASSUME.

I guess i should just give it a try and see what complications i het allong the way?

[Kinkstaah]

I know you're in Surname, so parts availability could be pretty fkin weird. If it were me I would be trying to get the correct engine ECU/TCM (integrated or otherwise) for the engine itself. There's not always a lot of wriggle room for when it doesn't work, as it'll just flat out not work.

That said what you have is pretty close, a RB25NEO with a Stagea ECU (... gtt?) but there's still some pretty big differences between the turbo stag motor and the RB25NEO Non turbo.

So it'll either be great or really damn annoying depending on how well you study diagrams and how well Nissan lego decides to fit together in the real world.

[GTSBoy]

Neo turbo ECU will shit the bed without the boost sensor. Will need to wire in a resistor, or one of a couple of other options, as detailed at Nistune.

[romel]

So a small update,

i continued with using the RB20 wiring on the RB25 trans and engine and the car runs good but i have to drive the car under 3000rpm otherwise its being rev limited and doesn't want to shift to another gear, i removed the ABS fuse and shifting went smoothly only thing is the KM and ABS doesn't work but i wasn't being limited till 3000rpm. 

So are their possibilities that the speed sensor 2 is creating issues?

and does anyone know where its located cause the RB25 trans has nothing on the tail like the C35 Laurel.