Jump to content
SAU Community

Rb25/30 Won't Idle Properly

crispyvl

By crispyvl,
in Engines & Forced Induction

 Share

Recommended Posts

crispyvl Apprentice

crispyvl

Posted
Posted (edited)

could not find anything on this topic for days so here is my problem

it will rev to 2000rpm and back to 1500rpm

rb30det w/ S1 rb25de head and std internals

rebuilt std vl turbocharger

rb25det exhaust manifold

S1 rb25det ecu. tried s1 rb25de ecu and s2 rb25det ecu

nizpro hidden intercooler

has anyone had a similar problem?

here is a video

http://www.youtube.com/watch?v=I0G05z-7mIU

Edited by crispyvl
Link to comment
https://www.sau.com.au/forums/topic/394398-rb2530-wont-idle-properly/
Share on other sites
bubba Grand Master

bubba

Posted
Posted

did you use a turbo block and pistons or NA block and pistons?

You haven't given much info.

But a factory ECU isn't going to run a different capacity engine, and different turbo very well.

Stock ECU or maps has idled fine on all my 30's, I would be looking for a vacuum leak or checking the afm connections.

GTSBoy Grand Master

GTSBoy

Posted
Posted

OK. I wouldn't have worried about non-turbo injectors, as going smaller is hardly going to help. If you've tried a different IAC valve, let's just be sure we're talking about the correct valve. There's two involved in the idling of the car. The IACV is the one at the back end of the plenum that is motor controlled by the ECU to control the idle speed at all times. The other valve is hidden under the plenum and is the cold start valve. It's electrically heated and is open when cold. As it warms up it closes off the extra air that it lets in for a cold fast idle. You don't want to play with that one, it's the IAC that's important. If you've changed the IAC with no change, are you sure that the wiring and connector for it is sound?

Also, do go look at the codes. You might find the answer right there.

DVS JEZ Grand Master

DVS JEZ

Posted
Posted

I had the same issue when i cleaned my throttle bodies in my first GTR.

Also in my old r31 but that was due to dud iac valve (idle motor)

Try crimping the hose that feeds the idle motor to see if the idle drops.

Make sure the throttle cable isnt over adjusted. Make sure throttle plate is fully closed.

Make sure idle adjustment screw is wound all the way in.

Make sure cooling system is bled

crispyvl Apprentice

crispyvl

Posted
  • Author
Posted

I had the same issue when i cleaned my throttle bodies in my first GTR.

Also in my old r31 but that was due to dud iac valve (idle motor)

Try crimping the hose that feeds the idle motor to see if the idle drops.

Make sure the throttle cable isnt over adjusted. Make sure throttle plate is fully closed.

Make sure idle adjustment screw is wound all the way in.

Make sure cooling system is bled

will it matter with no coolant because it doesn't have any in it what so ever

kitto Mentor

kitto

Posted
Posted

Sounds like a wiring issue to me.

I'm pointing straight to the AFM for the time being. I have seen similar things with dud AFMs / No AFM connected / Incorrectly wired AFM.

Because VL's wiring is SOOOO gay, and most people dont know how to correctly wire up RB's, most people miss the fact that some of the sensors have a separate power feed fed by a brown wire, and most people dont even both wiring up the crank signal, most of them run like shit.

I'd check the AFM, if you are not electrically minded, get a mate that knows RB's wiring WELL. Check for the obvious too, IE, vacuum leaks.

It is possible that the IACV doesn't even have power to it, one pin should have +12V when the ignition is on. The 0V for this valve is controlled by the ECU.

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
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • joshuaho96
      R32 GTS (RB20DE) Injectors Replacement

      By joshuaho96 · Posted

      Yes, it will take a fair amount of solution but the sodium citrate + citric acid + detergent is cheap stuff. Use laundry detergent instead of dish soap if you want to reduce the bubbles, also you could just buy sodium citrate and add some citric acid to the mix until you get to a weakly acidic solution if you don't feel like dealing with all the bubbling generated by adding everything together. For a fuel tank you need quite a lot of distilled water but it's probably worth the effort.
    • Dose Pipe Sutututu
      R32 GTST - 600KW+ RB28/CD009 Build

      By Dose Pipe Sutututu · Posted

      Actually looks like a Nitrous setup now 😆
    • Dose Pipe Sutututu
      Dose's Sometimes DIY and Pay Someone Home & Boat Improvement Thread

      By Dose Pipe Sutututu · Posted

      @robbo_rb180 I already have a NEO head on the shitbox 😎 Just needs beehive springs so I can rev it past the 8600 rpm limiter, then again pointless too, turbo is out of puff lol. Wen da gods let me win lotto eh?
    • robbo_rb180
      Dose's Sometimes DIY and Pay Someone Home & Boat Improvement Thread

      By robbo_rb180 · Posted

      Everyone I know with a90 supra at time attack aren't having issues with 3-5 fast laps so far and one is decent powered one too. Saw a k24 swapped 86 with a 8hp70 and big slicks and aero which had no drama's at QR and Manton Park. I've stuck a 25 row cooler in my setup with 8hp45/50 in the hopes of keeping the oil cool as I plan on some racing next year that 20-30min sessions. I've also geared my car so won't be using 7th and 8th gear too. @Dose Pipe Sutututu just needs to get that samsonas in already and have that tassie guy fit a head and rev it too 11ty thousand rpm. 
    • MBS206
      Mistakes were made, my R34 Story

      By MBS206 · Posted

      My embedded systems thoughts have me sitting with GTS on this. Variation between same phone hardware, should be small. However, the internal "intensity" or "volume" amount that say Google passes to the app, will be quite different, as the underlying hardware will be passing different levels for the same volume to the Google OS. Until the app creator has had each individual phone, and set benchmarks and calibrations for each, the amount of error can be quite huge.   It can even be observed by using different phones, recording the same noise, and then playing it back, they end up soon ding different. A big reason for it, is even the different types of mics used in phones have different responses, and different frequency ranges. Then you need to get into the DSP, and the variations in those, their sample rates which then effect their frequency range, and then the quality of the DSP, and what type of hardware conversion they do to for the ADC within the DSP. Oh, and let's not forget at the low level phones are designed to cutout loud sounds. It's one of the reasons they suck in really loud environments (eg concerts). The louder you yell, the more you'll get cutout too Note DSP is Digital Signal Processor ADC is the analogue to data converter. I don't have any real data on what the variation would truly be, however, chat GPT says in general, their output is typically between +/-2dB to +/-5dB of what you're really measuring. So realistically, anything from 4 to 10dB variation is possible even with the same devices.
×
×
  • Create New...