Er34 M800 Rb25 Neo

[icecoldbitch]

Hello Guys,

I have ER34 equipped with RB25 NEO engine with GTX3076 Turbo.

Motec M800 ECU was badly installed last year (OEM ECU plug was just ripped off and Motec connectors were wired directly to OEM Harness, added some subharness for MAP, boost control valve etc.) As a result, vehicle has different problems with ignition, erratic timing (optical trigger) etc, but the main issue is - ABS does not work completely.

Now I am installing M&W CDI ignition, Hall effect triggers, adding some units (Motec E888, Knock Control) and currently doing all the wiring by myself.

My question is - should I remain stock ECU and TCM to make ABS enabled or the reason of disabled ABS was different to availability of stock ECU and TCM for that car?

Hope for your help. Thanks a lot.

[GTSBoy]

There's a comms link that runs between the factory ECU, the ABS and the TCS computers. Without the ECU the others don't know what to do and fault out. So I suspect that if you want them to work, then you need the original ECU and the Motec both installed, with the Motec responsible for actually running things, the but the factory ECU at least connected up to enough stuff to power up and know when the engine is running and what rpm it's doing. Which might be difficult, seeing as the CAS is the device that gives engine speed and I'm not sure if you can have two ECUs watching that at the same time.

[XKLABA]

Though if you are going to put a hall sensor on the crank you can leave the CAS feeding the stock ECU for ABS etc and have the Motec reading the hall sensor to run engine, you will just need a phase signal from the cam

[icecoldbitch]

Thank you for feedback!

I have ROSS trigger system (Motec GT101 Hall Effect Sensors) and ROSS Crank Trigger Converter Box, so I guess stock ECU would know what rpm engine is running.

But is it really necessary ?? Or power for main ECU, TCM and its relays will be enough for enabled ABS (I mean remaining ECU, TCM and cabin connectors and relays plugged and wired together)?

Just do not want to get much additional Control Units in the car (I already had a headache to wire M800, Multi Steering Wheel, Motec SLM, E888, LTC, Knock control together...and also want to create traction control via Racelogic or M800, so there will be a lot of wires, do not really want to create more..)

As I found in Service Manual - stock ECU has some special "ins" and "outs" as

#37 - Throttle Opening Signal (it comes to TCM, so I guess if I remain them both - it will work)

#51 - Throttle Motor Sensor Signal

#53 - Motor Throttle Switch Signal

If ECU wont find them - will it be an issue for ABS ?

and interesting #79 - ECM TCM, TCS/ABS Integrated Control Signal (Multiplex communication), have no idea what it is....

Thank you for your help!

[GTSBoy]

and interesting #79 - ECM TCM, TCS/ABS Integrated Control Signal (Multiplex communication), have no idea what it is....

Refer to my post. That's the serial comms link I was talking about. None of those units are really happy in the absence of the others. At least with the ECU you can Nistune it and turn off the requirement for the other modules to be present (gets rid of the fault codes). But I'm not sure if you can get the ABS module to work without the factory ECU.

[icecoldbitch]

ok, got it. Thanks! Will try to wire it up and see what it gonna be...