Jump to content
SAU Community

Recommended Posts

  • Replies 101
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Posted Images

  • 5 weeks later...

Umm, I know I'm a bit Jonny-come-lately, but, which wire is it that people are cutting/switching? Sounds like something I need to do.:thumbsup:

Yeah Andy, you do! Everyone with a M35 should do this. Then crossing a busy road won't require such a big gap.

It's pin 55 on the ECU, but run it via a switch so you can "cut" the wire at will (& reconnect it also). If the ECU doesn't see the brake switch every so often (days normally) it will eventually throw a code. Good news is the code disappears if you switch the wire back into circuit & put your foot on the brake.

For more info have a read of this thread from about here (or even a few pages before -it's very interesting): http://www.skylinesa...ost__p__5832870

Edited by Commsman
  • 1 month later...

I found out today, after months driving with the wire cut, it will eventually go into throttle limp. I was driving when I suddenly noticed the throttle wouldn't go past 24% on the informeter. A quick roadside ecu reset didn't clear it, unplugging the ecu did as I couldn't get to the wires.

I have a switch in the dash now... :)

  • 3 months later...

>_< I'm getting DTC 1805. In theory once you flick the switch and press the brake does it go away? Or do you need to clear the code?

If its like other error codes Ive experienced in the M35 (eg dead AFM) the code wont clear automatically when the problem is resolved (ie plug the new AFM in and its still showing you a CEL - but the car is operating fine). If its no longer in limp mode, I would suggest that it will self clear over the next couple of days; but if you're feeling pedantic you can clear the codes manually thumbsup.gif

Funny thing is that I haven't noticed a drop in power, although I wasn't giving it much this morning. Better take it for a drive at lunch and see what's up.

If the limp mode caused by the wire cut is the same as the one with a blown AFM you'd definitely notice, even when not giving it much. Basically theres a ~2100 RPM rev limiter in place and it bounces off that once when you try and move your foot much more than 1/4" on the pedal.

If the limp mode caused by the wire cut is the same as the one with a blown AFM you'd definitely notice, even when not giving it much. Basically theres a ~2100 RPM rev limiter in place and it bounces off that once when you try and move your foot much more than 1/4" on the pedal.

Pure weirdness then. I'm sure it's 1805 but I would have revved it higher than 2100 RPM this morning. I know I was tired this morning but surely not that much! :rolleyes:

If its the wire cut you just have to reconnect the wire and press the brake, you will be good for another few months. If you leave it the car will go into limp mode eventually and limit the throttle.

If its the wire cut you just have to reconnect the wire and press the brake, you will be good for another few months. If you leave it the car will go into limp mode eventually and limit the throttle.

I just read Andys first post in this thread, he suggested that the limp mode imposed was that "Under hard acceleration = reduced response" which is a bit different to the rev limited limp mode. So, given how tired you were Jase you mightnt have noticed :P but as Scotty said - flick that switch you put in and see if it seems normal now?

I just read Andys first post in this thread, he suggested that the limp mode imposed was that "Under hard acceleration = reduced response" which is a bit different to the rev limited limp mode. So, given how tired you were Jase you mightnt have noticed :P but as Scotty said - flick that switch you put in and see if it seems normal now?

The above could be true as in my experience when the light came on (from the brake wire cut) I didn't notice any drop in performance or rev limit being imposed, but I also wasn't doing anything considered 'hard acceleration'. As for resetting the code, for me it was as simple as flicking the switch back to normal & pressing the brake pedal. Maybe it is different if the MIL has been on for a long time.... Also, I don't know how Scotty got a months driving between resetting. I got about 500km before my light came on.

Edit: just thinking about this - it's probably because Scotty has a light on permanently due to the Emanage. He is probably talking about a proper limp mode, which is quite on the cards if left for an extended period.

Edited by Commsman

^lol.

It's just 12V that needs to be applied to the ECU pin to clear the code. Can get it from anywhere. Of course if you don't use the original brake wire & switch in some permanent 12V, you'll have restricted throttle all the time.

I'm starting to think of a good idea for a "valet mode"....:whistling:

Yeah I get coming on around every 500km. Ive never noticed any difference, but its usually when im just cruising along so just press the brake slightly with my left foot while holding the button and the light goes out after a couple of seconds

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • The wiring diagram for the R33 RB25 is freely available, and is essentially the same same as most other RBs (just with differences as to which pin # does which job). To get the ECU to power up, you just need to provide power to the ECCS relay, and have the other power feeds that come in from the top left of the wiring diagram (wrt the ECU) that give perma power to the fuel pump relay, the ECU itself, etc etc, all connected. When you put power on all these it will just come to life. It's pretty clear from the diagram what needs to happen. Just follow the lines from the 12V + supply stuff in the top left over towards the ECU. I've even posted snips of such diagrams (not for vanilla 25, I think for Neo and 26) to various threads here in the last few months, talking about what it takes to get the fuel pump and FPCM up and going. Search these up and they will help get you started on doing the same with the vanilla 25 diagram. Hell, for all I know, I've done the same with that one in years past and have forgotten.
    • Yep...so unless someone posts up the answer you will need to probe from the ECU connector to the dash plug with a multi meter in continuity mode to trace the wires.  Note the ECU has multiple - and + (and across different key settings - Battery, IGN and Start) and most likely the power is fed from the connector(s) that is normally near the left hand headlight.
    • Thanks Duncan, I am actually just trying to get the Rb turning and running with the RB25DET S2 original loom itself  I am just trying to get it going outside the body and not thinking about the S15 or trying to match anything to the S15 loom at all I am only trying to see if anyone has done this and what pin they found to be the ignition trigger and ECU+/- on the dash connector, that's about it. Thanks  
    • Hi Guys, Does anyone know any aftermarket part numbers for a starter motor to suit the VQ25DET? I can find lots of alternative part number for the VQ35DE, which I assume would fit, but there is a lot of conflicting information out there. Thanks..
    • I don't understand how this hasn't boiled down to - Upgrade the turbo when you have everything required. ECU, injectors, fuel pump, turbo, etc. Do it all at once.  If you don't have everything required, just enjoy the car as it is and keep saving up your pennies. 
×
×
  • Create New...