BNR32 ECU into BNR34 Vehicle - ECU can connect, won't start

[Jono]

Hi Everyone

I have got myself a later model BNR32 ECU and installed a nistune. It will be going in my R34 GTR Vspec II.

I have:

Switched the Crank angle sensor wires (Did this internally) (51/41 and 52/42)
Bridged the Pin8 to Pin43 (Ignition signal pin is different between models)
Bridged O2 sensor GND (pin 50) to the pin used for heater GND by the R33 ECU (pin 115)

So with those mods done, I can see RPM on the Nistune while cranking, the O2 sensors register acceptable voltages. I have checked all other sensors and outputs, and no errors whatsoever. (Neutral switch, TPS, etc etc)

There are zero error codes reported. When cranking it simply has the code [21] Ignition start come up.

But it just cranks. No fire, no cough, nothing, Just cranks and cranks. Sometimes it blows the ECU fuse in the boot.

Can anyone help me with some ideas?

Thanks

Jono

[Matt]

Check the fuel pump output differences between R32/R34 because I think the fuel pump output might be a different pin
(What fuse exactly is blowing also?)

[Jono]

Thanks for the reply - I am actually having trouble finding a BNR34 ECU pinout diagram. Can you help me at all?

That is definitely something I will check

[Matt]

file attached. not the best quality but got everything on there. IMMU line would be ignored on R32 GTR ECU

[Jono]

Thanks for your replies

It is the "Engine Cont" Fuse in the boot that keeps blowing. It doesn't kill the ECU though, it stays powered and online, but the car just cranks.

I think there may be a short with a sensor, what I might do is unplug some sensors and see what happens.

Maybe the o2 sensors? I thought that if there was an issue with them though, that it would come up with a error code

[Matt]

O2 sensors will not cause those problems

[Jono]

Found the problem - I decided to start unplugging things. As soon as I unplugged the coil packs, it stopped blowing the fuse.

I had suspicions on this because once the fuse was blown, after a fair bit of cranking I could smell fuel so the fuel system was definitely working.

My friend also says he thinks the "Engine Cont" means Engine Continuous Power - which makes sense. This is why the ECU stays online. Obviously if the ECU fuse blew it would stop working and I wouldn't be able to connect to it with the nistune software, because I can.

Okay, so now I am stuck with this problem.

The R32 GTR had a ignitor box, the R34 Does't. I assume the wiring is different hence the fuse blowing.

Any ideas on how I could fix this? I have been looking at wiring diagrams but I don't really understand much of it.

[Matt]

Differences between wiring:

Pin 8 - Ignition switch (IGN) (R34) / Pin 45 - Not used (R34)
=> Wire pin 8 to Pin 45 (R32 ECU)

Pin 10/20 - Not used (R34)
=> Pin normally for Ignition GND (R32 ECU)

Pin 31 - Not used (R34)
=> Wire needed to be added for consult CLK signal (R32 ECU)

Pin 41 - Camshaft position 1 deg POS (R34) / Pin 51 not used (R34)
=> Swap to 42/52 on CAS 1 deg POS (R32 ECU)

Pin 42/52 - Camshaft position 120 deg REF (R34)
=> Swap to 41/51 on CAS 120 deg REF (R32 ECU)

Pin 54 - IMMU/NATS (R34)
=> Not used (R32 ECU)

Pin 57 - Not used (R34)
=> This pin has throttle sensor power supply output (R32 ECU). Not used by R34 wiring

Pin 107 - Not used (R34)
=> This pin has ground (R32 ECU). Not used by R34 wiring

Pin 115. Heated O2 sensor control signal
=> This pin not used (R32 ECU) so wire to be connected to pin 50 (control unit ground) on R32 ECU

With regards to ignition coils I assume that Nissan have remove the igniter module and the igniter's are now built into the coils (similar to the differences between R33 S1 and S2 models)

I wouldn't think there would be a wiring change there. However you may need to trace back where the power and ground come from the igniters

The R32 ECU has ignition ground on its ECU pins 10/20. Does the R34 ECU have any wires there? I cant see swapping the ECU would make difference here?

[Jono]

Differences between wiring:

Pin 8 - Ignition switch (IGN) (R34) / Pin 45 - Not used (R34)
=> Wire pin 8 to Pin 45 (R32 ECU)

Pin 10/20 - Not used (R34)
=> Pin normally for Ignition GND (R32 ECU)

Pin 31 - Not used (R34)
=> Wire needed to be added for consult CLK signal (R32 ECU)

Pin 41 - Camshaft position 1 deg POS (R34) / Pin 51 not used (R34)
=> Swap to 42/52 on CAS 1 deg POS (R32 ECU)

Pin 42/52 - Camshaft position 120 deg REF (R34)
=> Swap to 41/51 on CAS 120 deg REF (R32 ECU)

Pin 54 - IMMU/NATS (R34)
=> Not used (R32 ECU)

Pin 57 - Not used (R34)
=> This pin has throttle sensor power supply output (R32 ECU). Not used by R34 wiring

Pin 107 - Not used (R34)
=> This pin has ground (R32 ECU). Not used by R34 wiring

Pin 115. Heated O2 sensor control signal
=> This pin not used (R32 ECU) so wire to be connected to pin 50 (control unit ground) on R32 ECU

With regards to ignition coils I assume that Nissan have remove the igniter module and the igniter's are now built into the coils (similar to the differences between R33 S1 and S2 models)

I wouldn't think there would be a wiring change there. However you may need to trace back where the power and ground come from the igniters

The R32 ECU has ignition ground on its ECU pins 10/20. Does the R34 ECU have any wires there? I cant see swapping the ECU would make difference here?

Hi Matt

I have done exactly all of the things you have said above, and thanks for the info.

THe IMMU/NATS, just to make sure I pulled the wire from the harness and same issue.

Regarding pins 10/20 - they had me a bit suss too. I forgot to check the R34 ECU plug to see if there were wires there. If there are not, then I don't think that would be the problem. I will definitely check this afternoon and let you know.

Your assumptions regarding the ignitors are correct - They removed the ignitor box and put the ignitor in with the coilpack. Exactly like the R33 series 1 & 2.

I didn't think there would be a wiring change either - the ECU would simply fire the coil on the same signal wires and then you would have spark?

[Matt]

Just to close this thread off...

Pin 10/20 - Not used (R34)
=> Pin normally for Ignition GND (R32 ECU)

Wire 10/20 to pin 50/60 to provide the R32 ECU with an ignition ground reference. After this R32 ECU will work fine in R34 ECU after speaking to Jono today and getting it working

We will update the R33 GTR upgrade document to include R34 now with all the required changes to the ECU

[Jono]

Many thanks Matt! You certainly know your stuff.

Took the car for a spin last night - it runs so much more smoother than with the powerfc. The car even starts so much quicker and responds to idle control so much better.

Now I just need to get the Flex stuff sorted out and I'm all good.

Nistune is an awesome product, wish I had of used it years ago.

[Matt]

R32 Flex has been finished ready for testing. BNR32 is next on the agenda. Its almost done and just needs to be tested once I few a few free hours