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Low idle on warm car?

Posted: Mon Apr 03, 2006 9:23 am
by Rainey
Hi guys, the only serious issue with my car at the moment is the idle speed when the car has warmed up a bit. For example when I pull up to traffic lights the idle speed will slow to about 800 RPM and then it will suddenly drop to about 300 RPM and will gradually idle slower and then stall over about the period of a minute idling?

At the moment I've been heal-toe'ing it at lights to keep her from dying but with my lack of skill that could be dangerous in the long run! :oops:

Do I just need to adjust the idle speed or is there something else to it?

:beer

Posted: Mon Apr 03, 2006 10:59 am
by SIR GSR
You could have a vacuum leak....

I have the same problem when my BOV sticks open....

Posted: Mon Apr 03, 2006 11:59 am
by Rainey
Hrm, maybe thats why there is still so much dirt and leaves in the footwells. LOL

No seriously, how would I check that? Have you fixed yours or how do you work around the problem? And I've noticed that it doesn't happen all the time, sometimes it idles fine at about 900 RPM and other times it dips down to 300'ish.

Posted: Mon Apr 03, 2006 6:09 pm
by Junkers
What is the vacuum reading on the standard boost gauge when the car is idling at 300rpm?

Posted: Mon Apr 03, 2006 8:01 pm
by chunkhead
Fucking Vac lines!!! :x

Go and spend $20 and buy new vac line hose! Replace the entire engine bay and ensure there are none open. If there is just stick them into a hole, they seem to work! There is a map of where they all go if you do a search! Changing these will dramatically improve your car and get rid of numerous gremlins such as your problem!

I can't wait to finnaly get rid of them... :D :beer

Posted: Tue Apr 04, 2006 10:05 am
by Rainey
Okay, when the car drops to about 300 RPM the boost gauge reads about 16 below zero. But when it is idling correctly it still reads about the same, when I get on the gas the gauge builds up to the 0 mark and then of course when I am boosting it goes into the positive.

Low Idle on Warm Car

Posted: Tue Apr 04, 2006 8:13 pm
by Ric
I agree with Chunkhead from my own experience. Replace all the vac lines. It won't cost you an arm and a leg.

I had a high revving problem at idle particularly during cold weather and tried replacing a number of sensors including the air temperature sensor. All this cost me time and money and a lot of frustration.

The culprit turned out to be $1 worth of vac hose which ran from the fuel mixer body to the boost sensor located on the firewall. What had happened over time was a petrol vapour/rubber sludge had developed in this vac line and prevented a vac reading to the boost sensor. Remember these lines are only 2-3 mm inside dia.

When I removed this line I couldn't blow through it. It only worked on the car when engine temp. melted the sludge and allowed a reading to get to the booster.

There you have it. Replace all old vac lines and enjoy the purr of the 4G63 turbo engine.
Cheers

Ric

Posted: Wed Apr 05, 2006 10:45 am
by chunkhead
Yeah, I thought I lost a cylinder, engine was shaking all over the place, wouldn't go above 80kph and backfired flat out! After an extensive search of the engine bay I found a little vac line with no home was hissing! Covered the hole with my finger and car jumped back to life, idleing fine! :x I ended up replacing all vac lines, and found sludge in most of them! Thank-god the new engine has an aftermarket ECU and I can get rid of them!!! :D