Jump to content
SAU Community

Bump in idle

bbenny

By bbenny,
in Engines & Forced Induction

 Share

Recommended Posts

MegaGTS4 Proficient

MegaGTS4

Posted
Posted

bbenny,

Sounds like the AAC valve needs a clean as this basically controls the idle, although in the workshop manual it states that the idle speed, ignition timing,CO and HC density (airflow-meter) are inter-related. Any adjustment to one effects the others and requires an additional inspection.

To clean the AAC valve:

For RB20-25 motor

The AAC valve (Auxilliary Air Control Valve) is located at the back of the plenum chamber (inlet manifold) there is a maroon electrical plug (brittle) and a hose which need to be removed first then there is four ten millimeter bolts that also need to be removed before the whole assembly can be (careful if you want to use the orignal gasket again) removed from the car.

then there is two screws that hold the solenoid on, once this is removed the remaining assembly can be cleaned by useing carby cleaner (compressor to dry and clear any blockages) also make sure that the spring moves(smooth) and the valve works.

Reassemble in reverse order with a bit of sensor safe silicon with the original gasket(or you could make another one it depends on weather the gasket comes off in one piece)

To adjust idle speed From a workshop manual:

The screw that is located on the AAC valve is to control idle speed, But first you need to remove the ECCS control unit(computer) from the passenger side kick panel and there is a screw there that controls idle aswell, now if you can read japanese the writing near the screw says "CAUTION Adjust within indicated range. Do not turn with excessive force" Low idle is at the bottom with high idle at the top and just a little bit past the high idle mark there is self diagnosis. This screw needs to be turned to the low idle mark and the engine warmed then remove the electrical plug from the AAC valve and start engine, Idle should be at 900 rpm, if not turn screw on AAC valve assembly to adjust engine speed to 900 rpm.

Turn screw to the left (counter clock wise) to increase engine idle.

Turn screw to the right (clock wise) to decrease engine idle.

Once the target 900 rpm is achieved plug AAC electrical plug back in and observe if there is any change in Rpm if there is this needs to be adjusted at the ECCS control unit with a maximum of 250 rpm adjustment, another Caution if you turn the screw on the ECCS control unit near the self diagnosis spot it sets the engine speed at the lowest setting Rpm minus 50 rpm.

Sorry for the long and boring post!

MEGA

P.s the AAC valve is located under the plenum on the RB26 and the procedure is the same!

Link to comment
https://www.sau.com.au/forums/topic/19569-bump-in-idle/#findComment-411194
Share on other sites
predator Grand Master

predator

Posted
Posted

Can also be an airflow problem or your AFM is dirty.

I know after replacing my pod for the stock airbox (with cheap filter), it has less air going in and idles very "lumpy" at the lights. Idle revs jump a bit all over the place as it tries to compensate for the lack of air volume being sucked in.

Link to comment
https://www.sau.com.au/forums/topic/19569-bump-in-idle/#findComment-411427
Share on other sites
  • 1 year later...
Cubes Grand Master

Cubes

Posted
Posted

My slight bump/miss on idle is a dirty injector.

Origionally that is all it was. Now when idling at say 650rpm then stabbing the throttle that car hessitates/slight bump or slight miss then rev's.

Its not really a miss its a half arsed miss. :D

Link to comment
https://www.sau.com.au/forums/topic/19569-bump-in-idle/#findComment-1218686
Share on other sites

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

    • MBS206
      Duncan's V37.......race car?

      By MBS206 · Posted

      Even more fun, leave all the ADAS stuff plugged in, but in different locations, hopefully avoid any codes!   And honestly, all these new cars with their weird electronics. Pull all the electronics out Duncan, and just shove an aftermarket ECU and if needed a trans controller in, along with a PDM. Make it run basic but race car styled!
    • Duncan
      Duncan's V37.......race car?

      By Duncan · Posted

      To follow up a question from earlier too since I had the front bar off again (fking!) This is what is between the bumper and the drivers side wheel And this is the navigator side, only one thing but its a biggy! So basically....no putting coolers in the wheel arches without a lot of moving other stuff. Assuming I move to properly race prepping this car I'll take that job on and see how the computers respond to removing a whole bunch of ADAS modules
    • Duncan
      Duncan's V37.......race car?

      By Duncan · Posted

      So I prepped the car for another track day on Wednesday (will be interesting to see coolant temps post flushing out and the larger reservoir, with a forecast of 3-14 being 20o cooler than last time I took it out). Couple of things to mention; since I am just driving the car and not taking a support vehicle, I took the rear seats out and just loaded the back up Team Trackday style. Look at all that space! To cover off removing the rear seat....it is weird (note the hybrid is probably different because it wouldn't have folding rear seats) Basically, you remove the lower seat base, very similar to a r series but it is a clip that pulls forward to release the base rather than it being bolted down. Easy Then, you need to remove the side section of the rear seat on each side. There is a 14mm head nut at the bottom of the side piece, the it slides upwards off a hook at the top to release; you also need to unhook the seatbelt from the loop at the top. Then the centre piece is weird. You need to release/fold the seats forward with the tab in the boot on each side From there, there are 2,x12mm headed bolts holding the rear of each seat to the folding bracket, under the trim between the rear seat and the boot (4x christmas tree clips there, they suck). The seat is out but you can see where the bolts attach to the bracket
    • RP1421
      S15 Spec R

      By RP1421 · Posted

      As discussed in the previous post, the bushes in the 110 needed replacing. I took this opportunity to replace the castor bushes, the front lower control arm, lower the car and get the alignment dialled in with new tyres. I took it down to Alignment Motorsports on the GC to get this work done and also get more out of the Shockworks as I felt like I wasn't getting the full use out of them.  To cut a very long story short, it ended up being the case the passenger side castor arm wouldn't accept the brand new bush as the sleeve had worn badly enough to the point you could push the new bush in by hand and completely through. Trying a pair of TRD bushes didn't fix the issue either (I had originally gone with Hardrace bushes). We needed to urgently source another castor arm, and thankfully this was sourced and the guys at the shop worked on my car until 7pm on a Saturday to get everything done. The car rides a lot nicer now with the suspension dialled in properly. Lowered the car a little as well to suit the lower profile front tyres, and just bring the car down generally. Eternally thankful for the guys down at the shop to get the car sorted, we both pulled big favours from our contacts to get it done on the Saturday.  Also plugged in the new Stedi foglights into the S15, and even from a quick test in the garage I'm keen to see how they look out on the road. I had some concerns about the length of the LED body and whether it'd fit in the foglight housing but it's fine.  I've got a small window coming up next month where I'll likely get a little paint work done on the 110 to remove the rear wing, add a boot wing and roof wing, get the side skirt fixed up and colour match the little panel on the tail lights so that I can install some badges that I've kept in storage. I'm also tempted to put in a new pair of headlights on the 110.  Until then, here's some more pictures from Easter this year. 
    • joshuaho96
      R32 GTS (RB20DE) Injectors Replacement

      By joshuaho96 · Posted

      I would put a fuel pressure gauge between the filter and the fuel rail, see if it's maintaining good fuel pressure at idle going up to the point when it stalls. Do you see any strange behavior in commanded fuel leading up to the point when it stalls? You might have to start going through the service manual and doing a long list of sensor tests if it's not the fuel system for whatever reason.
×
×
  • Create New...