Low Revs When Car Is Stopped?

[tiesto]

Hi guys

I seem to have a problem with my rb20det

When i first turn the car on, it starts ok, but then the revs are around 0-200rpm and then I tap the throttle and it the revs go up nicely to around 900-1000rpm for warming up.

I take it for a drive, come back, or whilst driving I am stopped and the revs are about 0-200 to 500 and I have to tap it for it not to stall, like when Im stopped the battery light, hicas light etc turn on cause the car is about to stall so I keep the revs up... then when I've taken it for a drive, park it up and let it idle, it is perfectly 900rpm or there abouts.

Could anyone know what is going on or experienced a similar problem?

Battery is fine, alternator is fine. could it be throttle position sensor or AFM related? Could anyone please help?

[tiesto]

I'm going to take off the pod etc and check if has any cracks, because it isnt secured at the moment. Ive also found that if I move the pod up it changes revs and then I move it back down to current location where its hanging the revs die a bit, so there could possibly be a tiny crack in the piping there.. I will check it out when I add the bracket for the pod filter

[DFAULT]

i got the excat same problem

i changed the AFM, was almost perfect for about 2 months

now the problem has come back

tell me when you've fixed it

[tiesto]

so change the entire pod/afm or just the afm?

should i upgrade to z32 afm while im at it or just buy another stock rb20det afm?

[tiesto]

im gonna take apart pod now and clean afm with contact cleaner

will post results few hours

[tiesto]

ok well everything is disconnected

i dont know how the afm is supposed to be clean? is the top part of the afm black part supposed to come apart or what on a stock rb20det afm?

also i found that when the afm was removed, there was oil inside in the pipe , should i remove this pipe and clean it..

bit hard to get to the end of the pipe where the intercooler piping is covering it all

[Kryostaisis]

just try and clean it as much as you can with the contact cleaner, the afm is one peice, dont try to fiddle around with it or you can stuff up the AFM, try and get most of the oil and residue off it as possible, dont touch the "hotwires" at all. just spray

if there is alot of oil, could be a shafted turbo, but could be just years of buildup

it should fix your idling problem, i try to clean mine every few months

good luck

[tiesto]

ok well afm cleaned thorougly

and then i removed piping

cleaned tps as it was covered filthy with black dirt so its nice and shiny

took it for a spin, perfect, no idle problems

i came back, to adjust the revs to make them lower (it was idle at about 1000-1100rpm) and then i lost the small nut under the throttle body where it has a small screw head to adjust the revs (i think thats where it is).. not far from the aac valve

im about to find a new nut for it and put it on, but i took it for a spin without the nut and the revs were back to playing up again, does anyone know? will respond when i got the nut in and its all tight

[tiesto]

ok everything is bolted back up togethor

took for drive, let it warmed up

still has the same problem, come to a stop whilst driving and then the revs drop really low and battery and hicas light flash and come on

i have to tap it and then the revs are perfect 800-900rpm just under 1000rpm

could it be the little gold tube (iac solenoid?) which needs cleaning? almost impossible to get the bottom screw from this part (one with the brown adapter connected to it)..

or should i try a mates afm, which i know is working on a rb20det.. since this could still be afm problem?

edit - also when the revs drop down and idle becomes low, there is a kind of screeching noise coming right from above the plenum, where it says eccs. but when it idles fine the sound isnt there. anyone had this problem?

Edited April 22, 2006 by tiesto

[ORIGIN]

do you have an aftermarket bov venting to atmo???

[tiesto]

nope

stock bov

i just cleaned the aac valve

it was dirty as f*k

its sitting in carby cleaner right now

gonna try tomorrow let yas know

also have another green label rb20det afm i will try if aac cleaning did not fix

[cowie165]

It sounds very much like the common fuel pump problem. The very first post from 2002 should explain it all.

Try here:

http://www.skylinesaustralia.com/forums/in...p?showtopic=408

[tiesto]

i shall give this a go

if when i put my aac valve back in

ta

will post results soon

[tiesto]

aac valve was cleaned

put it back in and still no luck

i disconnected o2 senser, a little bit better but still wants to stall

when i approach a corner/intersection in gear and slowdown in gear and leave it in gear with clutch in, it doesnt stall

its only when u come to a stop or turn and roll it in neutral and then stop it starts to drop out so have to tap it to keep it up

oh and i replaced the afm with a working rb20det afm i know of a mate let me borrowed , still the same

any clues?

[paulr33]

try ecu reset. 02 sensor wont cause it to stall

[tiesto]

yeah i've reset the ecu

disconnect battery

hold brake for 30secs

and then start it up again

it only happens when im driving the car and coming to a stop or turning at intersections. gotta tap it to keep revs up but then it stays perfect 900rpm idle

could it be throttle body getting stuck and having to tap it to get it up again

i've cleaned throttle body/tps/aac valve i might try the throttle body again

[Freddy Kruger]

hows your fuel filter etc?

[tiesto]

im in the boot now

checking out my fuel pump

where is the fuel filter?

i'm going to ground the fuel pump's ground wire to the chassis

that way you can get fuel all the time and when in idle more fuel will come in i read it in another thread.

[rob82]

yeah i've reset the ecu

disconnect battery

hold brake for 30secs

and then start it up again

it only happens when im driving the car and coming to a stop or turning at intersections. gotta tap it to keep revs up but then it stays perfect 900rpm idle

could it be throttle body getting stuck and having to tap it to get it up again

i've cleaned throttle body/tps/aac valve i might try the throttle body again

Check TPS is still working and is set in the right position. It also sounds as though the idle bypass screw within the AAC valve isn't set right. What is meant to happen is that when you come to a rest the TPS should register 0% so then it sets the right duty cycle on the AAC valve to gain the desired idle rpm (850rpm). Now if the TPS doesn't register closed throttle then the AAC valve will not try to control idle and hence stall. The AAC valve itself should only control about 20-25% of the total air thar the engine needs at idle out of gear AC off, the bypassed air will deliver the remaining air required.

[tiesto]

when i start it, the car finds it very hard to find revs

by this i mean when i turn the key it ignites

revs go from 0 to to 100 then prob 200, back to 100, give it a tap and it goes up to 900, on cold starts you have to keep tapping it after it goes to 900 sometimes it drops back straight to 0 then 100 to 200. then after its warm it idles perfect 900

coming to stops/intersections does the same problem.

will check out what you said, rob82, and will reply