Jump to content
SAU Community

Recommended Posts

I cleaned out the AAC the other week and had the put the idle screw back in.

Will screwing it in decrease the idle or increase the idle?

Can it only be adjusted while the car is turned off or does the car need to be running while

its adjusted.

I tried to adjusted the idle screw while the car was running but the car would rev up and come back down to the same rpm as prior.

To set the base idle, I think you have to disconnect the TPS first. The revs should drop, and that is your base idle at which you can tune. The ECU does the automatic choke kind of action to keep it alive, or keep it high when cold etc.

I use a consult cable and software, and most of the software allows you to adjust the base idle.

thats correct. disconnect tps, start engine. give it a couple of revs - up to bout 2- 3 grand, then adjust the screw accordingly. clockwise to increase idle, anti-clockwise to decrease idel.

And what is the tps? throttle position sensor? If someone could put up some photos, I would appreciate it. I have a rb25. Ive done everything else except this (cleaned and siliconed up coils, cleaned every sensor with contact cleaner, changed plugs 3 times) and the idle is still all over the shop and it hesitates at about 5000rpm when i put my foot down. It boosts up but something is holding it back.

The idle is all over the place, would that effect performance like I have described?

Well, disconnect throttle position sensor (big black box on throttle body)

start car

rev few times

adjust idle screw

check revs by looking at the dash. Should be 650-700rpm I beleive? Check the sticker under the bonnet somewhere.

turn car off

reconnect TPS.

Timing can be checked using SydneyKid's guide. He wrote it up as part of a timing belt change on a Stagea, look in the model-specific section.

No pics from me! I'm going to work in an hour or so.

Edited by RANDY

Back of the inlet manifold (plenum) there's a blocked off (yellow plastic) hole, and a pipe that runs to your stock boost sensor. Next to the yellow plasticy bit, there is a screw there.

I did a search and finally found the brilliant post that I was looking for!

http://www.skylinesaustralia.com/forums/in...opic=110431&hl=

5000rpm problem has it's own thread somewhere too. Turns out that 90% of the time it's due to hair-line cracks in your coil pack(s).

Aroldtite(sp?) seems to be the best compound for sealing the crack.

silicone? i'd be pretty tempted to do it with glue... silicone doesn't stick as well as i'd like it... fine for plumbing, but I think with heat and metal surfaces it may come loose?

No other ideas, sorry!

It completely misses for half a second to a full second when booting it, right? If so, it's the right problem for the solution, but it could be a number of other things..

Possibly fuel pump leaning out, or ECU retarding timing if you're running higher boost... too many variables. =-[

To clarify how you adjust the idle, i've written the correct procedure below as the RB25 and RB20 procedure is different.

On the RB20DET (as asked by the thread starter)

Make sure the car is at operating temperature.

Make sure ignition timing is 15deg btdc @ 650rpm.

Disconnect the AAC Valve connector to stop the ecu controlling idle.

Adjust the idle screw to 600RPM.

Clockwise will make it decrease (screws in blocking the bypass passage and less air means less rpm), Anti-clockwise will increase the idle (screws out opening the bypass passage more and more means more rpm)

Reconnect the AAC Valve connector and the idle should be approx 650rpm (+ or - 50rpm)

If the idle is higher, make sure the diagnostic screw on the ecu is fully anticlockwise as this can increase idle if not fully anti-clockwise

On the RB25DET (not asked by the thread starter)

Make sure the car is at operating temperature.

Make sure ignition timing is 15deg btdc @ 650rpm.

Disconnect the TPS connector to stop the ecu controlling idle.

Adjust the idle screw to 650RPM.

Clockwise will make it decrease (screws in blocking the bypass passage and less air means less rpm), Anti-clockwise will increase the idle (screws out opening the bypass passage more and more means more rpm)

Reconnect the TPS connector and the idle should be approx 700rpm (+ or - 50rpm)

If the idle is higher, make sure the diagnostic screw on the ecu is fully anticlockwise as this can increase idle if not fully anti-clockwise

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

    • It is a kunfine Android screen . Does anyone know the wirering diagram of the fuga ??
    • just an update to this, poor man pays twice  Tried sanding down the pulleys but it didnt do the trick. Chucked another second hand alternator in the na car which I got for free off my mate and its fixed the squelling. Must have been unlucky with the bearings.    As for my turbo car, I managed to pick up a cwc rb alternator conversion bracket + LS alternator for 250 off marketplace, looked to be in really good nick. Installed it , started the car and its not charging the battery.... ( Im not good with auto elec stuff so im not sure if this was all I needed to do but I verified such by using a multimeter on the battery when the engine was running and I was only getting 12.2v )   I had to modify the earth strap for the new LS alternator , factory earth strap was a 10mm bolt which did not fit the bolt on the LS alternator which was double the size so I cut it off , went to repco bought some ring terminals that fit, crimped it onto the old earth strap and bolted it up to the alternator , started the car and same issue. Ran like shit and was reading 12.2 at the battery.  For a "plug and play" advertised kit thats not very plug and play but alas.  My question is , am I missing something ? Ive been reading that some people recommend upgrading the stock 80 amp alternator fuse to a 140 amp but I dont see how that would stop the alternator charging especially at idle not under load.  Regardless ive pulled it out and am going to get it bench tested by an auto elec tomorrow but it would be handy to know if ive missed something silly or have done something wrong.   
    • My wild guess is that you have popped off an intake pipe....check all of the hoses between the turbo and the throttle for splits or loose clamps.
    • Awesome, thanks for sharing!
    • To provide more specific help, more information is needed. What Android screen? What is its wiring diagram? Does the car's wiring have power at any required BAT and ACC wires, and is the loom's earth good?
×
×
  • Create New...