base idle
is there anyway to reset the base idle? without taking it to the mechanics?
yea its possible but i think you need an external tacho or sumin not 100% sure, just wait for sum other to read
With my VS i reset as follows:- Warm vehicle up to operating temp, Clean throttle body out with carby cleaner or similar spray, turn vehicle off and disconnect IAC valve and remove plastic cover from idle screw, Start vehicle and notice revs on dash tacho or similar, Adjust Rpm to around 1500rpm or slightly higher, Turn vehicle off and reconnect IAC valve. The reason the idle is so high with the IAC valve disconnected is when the vehicle is turned off the IAC valve is automatically moved to fully open to assist the next start. See how this goes
sweet il give it a go, but sorry whats the plastic cover from the idle screw?
its just a cover that goes over the screw, mines not on there, i think it fell off or suminOriginally Posted by daniel VR
so what is your base idle?
When I am sitting in Neutral or Park i idle at about 2,000 when i shift into Drive and keep my foot on teh brake (obviously) the RPM's drop down to around 1000
Makes for a bloody noisy car when waiting in teh Drive through.....
sorry im a bit confused about the "plastic cover from the idle screw"!!! i know there is the conection to the iac valve and the valve itself, but i dont know about the idle screw and plastic cover......
look above the iac just under ur thottle cable
is it the throttle stop screw? im looking at a diagram and thats all i can see.
Base idle is the idle speed with the IAC port blocked. I'm not a big fan of adjusting base idle without a good reason, like engine mods. There may be a case to do so if the engine has some wear on it but i would look to other things first.
Before attempting any adjustment, ensure that everything else is right first, like engine tune items. The throttle body should be clean(ed) as the amount of air flowing past it, which is what is being changed by moving the throttle stop screw, is affected by build up on the edge of the throttle plate. Cleaning is best done with the t'body off the car and the Idle Air Control motor removed (the IAC is the cylindrical component attached by two Torx screws). Use a rag soaked in solvent, kerosene works well, to wipe the inside of the t'body, IAC air port, IAC motor tip and throttle plate. Take care, as it is possible to bend the throttle plate. Using carburettor cleaner from a pressure pack, as is commonly done, can result in the grease being washed from the throttle spindle and IAC motor spindle, so don't.
The green cover is an anti-tamper device for the throttle stop screw which is what needs to be moved to adjust base idle. if it is missing, it means that someone has already moved the screw, generally to a position other than where it should be.
If you still think that you need to adjust the base idle, remove the green cap and mark the positon of the screw so at least you can go back if necessary. You will need a tachometer. The ones in the dash are not very accurate, so an external one is best. Many automotive multimeters will have this function built in. With the throttle body (and IAC) back on the car, warm the car to operating temperature and bridge the diagnostic terminals on the diagnostic link under the steering column. This locks the ignition timing to 10 degrees and prevents the idle being changed by the ECM altering ignition timing. Remove the inlet air duct and elbow. With all accessories turned off, including the engine cooling fan (you will have to wait as it cycles on and off), block the IAC air port with a finger and adjust the idle screw, if required, to achieve 450-550 rpm. Note that the engine will almost stall at this speed and you will burn your finger on the throttle body. Put everything back together. Expect the idle to flare when you first allow air past the IAC port, as the ECM will have been trying to correct for the low idle speed caused by blocking it. That's pretty much it. You can allow the ECM to relearn a base IAC motor position by idling in the various combinatiopn of A/C on/off, drive/neutral but just driving the car will achieve that.
wow!!! thats some great information!!! thanks!!! the thing is iv cleaned the throttle body and iac valve like you said. the idle was great for a 5 days or so then it went back to a rough idle that would miss every so often. i just dont know what else it could be? could it be the stop screw out of wack? :b:
2000 RPM??? I dont think mine idles that high..ill go and check later on
Have you checked fault codes ?
Last edited by Michelson4301; 28-09-2005 at 10:17 PM. Reason: back dated too far
If you were asking me....
I have checked the fault codes and my O2 sensor is stuffed.
There are some other Gearbox related codes but obviously that shouldnt effect Netural RPM's
Its a dual fuel setup and I checked today... its about 1800 RPM's for both Petrol and Gas. I thought it may have been specific to the Gas as they have a seperate tuning method.
Will definatly look at cleaning the Throttle body in my case as well as checking the fault codes again... a new one could be in there since I last checked. But that said I am pretty sure its been at that Idle for the last few months.
Its an old Ex-taxi that I got given for free... who know's what could be wrong with it... but I get about 350-400kms out of 50 odd litres of gas so I can't complain considering what I paid for it.
IAC problems
Hi everyone hows it going? I have been having massive problems with the idle of me vn, so I adjusted the idle screw thingy greatly so me car would idle, worked well, but I wanted it fixed properly so i came on this site and read what other users have written. So i removed the throttle body, and the Iac gave them all a good clean up and refitted, the little spindle thingy on the iac was serverlly covered in carbon and so was the chamber it seats into. After that car idles a lot better and now i can hear the the iac working (sukking sound) as i have a pod fitted. If anyones interested i own a 90Vn v6 running a performance chip , 2 1/2" sports exhaust from cat back and a pod filter, 15" mags 225/50 all round. Cheers
2000rpm idle wtf it suposed to be like 800 in netural and park and 750 in drive and reverse
yep, idle at 2000rpm and ull loose a bit of fuel just idling
is there a picture diagram or something to clean throttle body and iac I know nothing!!!
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