Help: Wiring Harness Conversion (series 1 To Series 2)

[jerry]

Hi,

I am in the process of putting in a Series 2 engine in a series 1 R33 Skyline. I found the wiring harness is different for the two (including the ECU). How do i install the engine and wire it up properly if the harness is different? I know i have to use the series 2 ECU and i have change over the air-flow meter(i have both these parts).

Do i put the series 2 ECU on the Series 1 harness and wire up the engine and engine bay plugs. This seems easier.

OR

Do i pull out the series 1 harness, put in the Series 2 harness with ECU and wire up the engine plugs and engine bay plugs. If so what are the modifications required. Some of the S2 plugs wont fit on the engine bay!

Your input would be much helpful. Kinda stuck at the moment on what to do.

Cheers

Jerry

[BH_SLO32]

Jerry,

I would suggest the easiest option would be to use the Series 1 harness together with relevant series 1 sensors (eg AFM, CAS, TPS etc) otherwise you will have to rewire part of the series 2 loom to ensure power feeds etc are correct. As an example, the power feed for the injectors is sourced from different locations and this would need to be considered.

Incidentally the series 2 R33 ECU will run a series 1 R33 motor via a series 1 loom.

Hope this helps.

Cheers,

[jerry]

So there are no worries in connecting a series 2 ECU to the Series 1 harness? I will thus use the series 1 wiring loom to drive the series 2 engine. Is that how you see it (apart from modifying the various sensors)?

[BH_SLO32]

So there are no worries in connecting a series 2 ECU to the Series 1 harness? I will thus use the series 1 wiring loom to drive the series 2 engine. Is that how you see it (apart from modifying the various sensors)?

The only difference I am aware of between the pinouts of the series 1 and 2 ECUs is apparently the series 1 ECU earths the Fast Idle Compensation Device (FICD) whereas the series 2 don't. Having said this I recently modified a series 1 loom for a member to suit his cefiro and I discovered that although his loom was a series 1 it did not earth the FICD through the ECU (pin 36). Incidentally he used my series 2 ECU briefly without any problems.

For your info I modified a series 2 loom to suit the Rb25 conversion into my R32 so have had the opportunity to work on both series 1 and series 2 looms.

The series 2 ECU will work with a series 1 loom you should just check if the series 1 loom has a wire at pin 36. If it does you simply need to cut this wire and earth it if you are going to use the series 2 ECU and thereby retain the use of the FICD.

Is there any reason for wanting to use the series 2 ECU over the series 1 given you are thinking of using the series 1 loom?

Hope this helps.

Cheers

[jerry]

I have been told that i have to use the Series 2 ECU for my Series 2 engine. The coil packs are driven differently and there are few other differences.

From what you have explanied.....

1) i shall retain my series 1 harness so all the power leads fit and i don't have to rewire;

2) i shall put in the series 2 engine and wire it up (chaning various sensors);

3) i shall plug the series 2 ECU into the series 1 harness

Is this how you see it.

I hope there are no problems with this.

Thanks in advance for your response.

[BH_SLO32]

Jerry,

You will need to use the series 1 coilpacks and power transistor. The series 2 coilpacks have the transistors built into the coilpacks. You simply need to install these with the associated harness that lies underneath the central coil cover.

As mentioned previously, retaining the series 1 harness will require use of most of the series 1 sensors thanks to the different plugs used between the different series eg Crank angle sensor, TPS (?), airflow meter.

In summary, the series 2 ECU will operate a series 1 motor so if you are unsure about a sensor I would suggest you use the series 1. As a little comfort the Apexi PFC for the series 1 and 2 R33 RB25s are the same. Don't forget you can use the series 1 ECU if so desired.

Refer also my previous post re FICD control.

Hope this helps.

Cheers

Edited March 23, 2006 by BH_SLO32