RB20det problems

[rbs13]

mine stalls if i pull the plug??? is that normal.. i put the idle down to 1000rpm today and it stalls like a bitch at every traffic light.. but is alright after a while of sitting there.. i also listened VERY closley and could hear a air leak some where. im pretty sure now that this is my problem just gotta find the air leak..

[R31Heaven]

If you adjust your idle off the AAC valve as you should, make sure you disconect the electrical lead as it will try to compensate every time you turn the screw and **** up you idle.

[Col-GTSX]

Im playing with it tommorrow.... so ill post after some play time

[BHDave]

Just to throw more fuel on the fire....

My car does this (did this). I changed the fuel pump on the weekend and found the severity of the surging (if you can call it that) was reduced significantly, most mornings i can't even feel it anymore.

Which leads me to think it may have something to do with the fuel pump voltage controller, which drops the voltage to the pump at idle and cruise to quiet it down and improve it's life span. You may find it's switching between high and low pressure or something when the car is cold and trying to pump more fuel in?

I don't really know it's this, just theorising based on my experience.

[rbs13]

i get this all the time not just when its cold.. but thanks for the coments im sure itll help. mine just idles like it has big cams in it.. VERY VERY annoying and even makes the car shake a little bit... really pisses me off!!!

[Sciby]

I know this is for an RB20, but I had some very weird behaviour in my 33... hunting, lack of power, etc... then stopped the hunting, just ran shite... turned out to be the coolant temp sensor. I mention this because we (the mechanics and I) thought it was the o2 sensor at first... then the AFM.

To test this, go for a drive, get everything nice and warm, then yank the cable off the temp sensor. If the engine doesn't go nuts and rev and carry on, then it's that. And if it does, just pop it back on, all good.

Free engine self-diagnosis, gotta love it.

[rbs13]

where abouts is the temp sensor? what do i pull off?

[Sciby]

Okay... erm... hard to explain without a picture, but standing in front of the engine bay, look down towards the oil filter... in your way will be a 2" sized pipe, with a sensor situated about 4 inches out from the side of the block, on top of the pipe.

Hope this helps. If it doesn't, I'll find a photo.

edit: Oh, and the pipe will be leading into/away from the radiator.

[rbs13]

ahh.. well was going to check it.. but just found out my headgasket is ****ed.. YAY!!!

[Sciby]

Doh, that'll do it.

[Col-GTSX]

OK... I found one of the problems.... The serging of idle is being caused by the ACC Valve. Located at the rear of the plenium chamber. However all said and done... try and find one... I have disconnected it completelly and the car is not serging...

However the stalling is still happening. I thought it may be the fuel pump so i have re-wired the fuel pump to be on high presure all the time. I alos have a fuel pressure reg with a gauge so i can see the preasure is not dropping when this happens. As mentioned earlier in the piece i replace the 02 sensor. Today i did some spark plugs.

Now the Acc valve seems to be a solinoid... It is a closed circuit and when voltage is applied there is not movement in the valve... My question is how does it work and whats its purpose exactlly??? The operation of the valve is funny, you can push the tip in about 10mm and it will spring back, this corosponds with another tip on the plenium... It does not send signal as i said before its closed circuit... So im assuming its a soliniod... but it does not puch out so im beet... Any ideas...

Also im pretty sure the stalling and carrying on is cause by a faulty sensor of some sort.

Also about the colant temp sensor, if you disconnect this sensor the car should return to a high idle, this is caused by the computer going into limp mode. Has nothing to do with wether its faulty or not....

I have replaced 2 before with no changes (this info is from the guys who replaced it)... On the bright side the colent temp sensor on the rb20 is the same as a nissan Maxima so the cost of getting one new is only $50 from Nissan...

Anyway guys, i think its time to through the whole thing....

I have spend over 15g's on this car and still its one prob after another...

[goofy]

Mate had the same thing to my 32 stalling like a bitch just screwed the idler screw up to 1200 rpm all gone does not stall now

[rbs13]

thats what i did.. but i screwed mine to 1500.. wow.. sitting in traffic and couldnt hear much (3.5in exhaust and 1 muffler) got too annoying.. col-gtsx - when i replace my motor ill lend you my spare idle control valve and you can try it. not sure when it will be but ill let you know and if you still got problems well give it a go. another thing to try is look at EVERY VACCUME line in your engine bay!!! try fuel filter if it hasnt been replaced for a while.. your fuel reg could be stuffed (you said you have an adj one.. have you taken the vac line off the std one and just let the fuel run through it? could have a leak some where) hate to say it but my head gasket is causing my idle to screw up.. mite be worth a check. the other nite i got the contact cleaner out and cleaned some of my coil packs also noticed on the wires going to the coil packs (the loom thing) that a lot of the wires didnt look the best.. looks as if they were burnt etc.. it would be a nitemare but mite fix it if you replace the wires () haev a look at the back of the plenum but under it and you will see another regulator type device on the fuel rail whats this for??? have a look at the vac line going to that is it cracked i changed mine and tried taking the one that was on there off.. took a while cause it was the original one.. there are just some things i was thinking about tonight. hope it helps.. if anything can/does at all..

[R31Heaven]

Col-GTSX the AAC valve pulses to adjust to tiny a/F changes keeping revs constant, the best I can describe it. Also a RB30 AAC valve fits so go to a wrecker and get one. Oh and if your AAC valve is stuffed by what you have found, it will stall.

[R31Heaven]

Also have you checked your Air Regulator ??? this is for cold starts, it is open when cold to bring revs up when cold starting and closes up, as your car warms up, bringing revs back down to normals. If this is broken/stuck your car will be a beach when cold.

[Col-GTSX]

Yes.... the cold start item will play up when the engine has passed about 150k's but has no real direct affect with the operation.... cant stall the car just makes it a bit jerky on the pedal when cold... but this cant be helped anyway...

The AAC valve is certainlly the cause.... I am replacing it next week with a gen part.... but ill do the collant temp sensor as well as this after noon i droped the endless chain on it and broke the %$#ing thing....

[Col-GTSX]

My issue sound very similar to this one

http://www.skylinesaustralia.com/forums/sh...4564#post814564

abve i talked about the timing changing all of the place and this can cause it.... Well in the post above another guy has measured the timing when the fault occurs with his motor and its all over the place....

Only 3 things control the timing...

1> CAS

2> ECU

3> AAC (in directlly thro ECU)

Ummmmmm ideas.... Anyone got a spare CAS for a silver top i can borrow for a week????

[Col-GTSX]

OK... problem gone for like over a week now...

Then as im starting to be a little happy about it... this arvo it did it again.

Revs up and down... get out of the car, unpluged the AAC valve and the car returns to normal... However with this unplugged it has a tendancey to stall un-expectlly... So i got to cross a major road in Brisbane to limp it home and what happens.... Yep you guessed it...

Then to make things even worse. The Police were sitting waiting for me to push it out of the way only to give me a hard time.... It took them 20 minutes of checking the car inside out to find that its perfectlly legal.... However they didnt look at the rego sticker which had expired over a month ago....

Because the car has been off the road for a while i forgot all about it...

Anyways they were pretty nice in the end... I guess they deal with some pretty nasty people everyday. But still thats 20 minutes of my life ill never get back.

Back to the story... Saving at the moment for a full and i mean 3 day type full service and tune... New AAC valve should be here in a few weeks from Japan ($300) then tune and all should be good.... In the mean time ill just drive it a little to keep the juices flowing

[Sciby]

Better that the cops are nice about it in the end rather than start making stuff up, or being *really* picky.

[Col-GTSX]

OK guys... the problem is solved.... Yes you heard me i fixed it...

Cost $40

Time taken 10 minutes

Faulty AAC Valve... Hardest part was trying to find the part.... Only taken 3 weeks, but anyways not the point... Im over the moon now... I can finally get the new FMIC done in the next couple of weeks... Then is the AVC-R... Then ill see you a jamboree... Wanta (im mean gonna) crack mid 12 second pass....