RB25DET idles like its haunted

Discuss the RB20, RB25 and RB26 series engines.
kpnitrl
Posts: 36
Joined: Thu May 08, 2008 7:09 pm

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S13 with S2 RB25DET Greddy IM & Q45 TB.

When I turn it on, the car revs by itself, and does that for as long as it is on. I tried messing with the throttle seeing if it would hold a steady rpm, but does not respond to the throttle being opened. Problem with the TPS Im guessing?

So I unraveled my wiring at the tps and compared it to what I have found online, but now Im double lost.
This is the info I found

RB25DET TPS wire---------Q45TPS Wire
Red-----------------------------White-------------(5v)
Yellow/Black-----------------Red/White------(Earth)
Black/Blue--------------------Black/Yellow---(Signal)

Problem is, my wires on the RB25 dont match up exactly. Plus, as Im looking through the FSM, Im thinking that I may have them connected wrong. Also, Ive been out of the country for about three years and wired it over four. so memory is of no use to me.
Im cross checking the wires coming out of the ecu later today, but wanted to see If Im at least on the right path
Heres a pic of my current wiring:
Image


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Carl H
Posts: 5985
Joined: Mon Aug 04, 2003 4:09 am
Car: 1995 Nissan 240SX SE RB30DET

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did you disable the vh45's coolant based cold idle spring?

kpnitrl
Posts: 36
Joined: Thu May 08, 2008 7:09 pm

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Yes. But Oddly enough, when I had that on it just reved high, but at a constant rate. Ever since I removed it, its had the fluctuating idle

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Carl H
Posts: 5985
Joined: Mon Aug 04, 2003 4:09 am
Car: 1995 Nissan 240SX SE RB30DET

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wiring is wrong for the 25, its black/blue = ground, sheilded red = signal, yellow/black = power.
middle pin on the q45 tps connector is signal, red = power, b/y = ground.

kpnitrl
Posts: 36
Joined: Thu May 08, 2008 7:09 pm

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Thanks for the affirmation of my faults Carl, lol.
So I wired them correctly. But. Now when I crank it, it starts... And then dies, tried it a few times with same results. But if I give it gas it responds. So at least I have throttle control.
Im getting fuel, spark plugs are new.
Think timing might be the problem? AAC valve?

supersayianjim
Posts: 308
Joined: Wed Nov 26, 2008 6:02 am
Car: 89 240sx(s13)

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bumping from the dead. why?? because I need to remove the spring he mentioned.


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