Idle on stock s3 304 ute

Holden/Delco Tuning. ALDL, OBD 1.5. Circa 1989 to 2004.
The J'rod
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Re: Idle on stock s3 304 ute

Post by The J'rod »

it's not the butterfly I will check again though
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vlad01
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Re: Idle on stock s3 304 ute

Post by vlad01 »

how does it run?

3 possible things come to mind.

Intake valve spring broken hence the question.

intake manifold gasket is broken.

Stuffed brake booster letting air in.
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immortality
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Re: Idle on stock s3 304 ute

Post by immortality »

Grab a can of Start Ya Bastard and spray it around all the places it's common to get vacuum leaks. If/when the revs increase you have found the vacuum leak.

Been a MAF based system all air entering the engine must pass through the MAF. IF you have fitted something like a catch can then it will need to be fully enclosed system or it will effect the engine tune.
The J'rod
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Re: Idle on stock s3 304 ute

Post by The J'rod »

It runs horrible when it's cold, it's like driving a carby 308 with manual choke, as it gets up to temp it runs ok but the idle can still be high like 1500, then if I turn car off once up to temp and restart it idle settles down and sits where it should, but without touching the accelarator at idle it can then rise up to say 1200 then come straight back down to normal idle.

Hope that makes sense.

thanks for your help to vlad01 appreciate it.
immortality
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Re: Idle on stock s3 304 ute

Post by immortality »

A speed sensor (VSS) error can cause idle issues as the PCM doesn't know when to go into idle mode. You would be able to see that in the logs.

Seeing as the idle does come right sometimes it is most likely that it's an electronic issue rather than mechanical.
The J'rod
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Re: Idle on stock s3 304 ute

Post by The J'rod »

That's what I've been wondering immortality, whether there is something going on with the wiring to the IAC, in a previuos post I was asking what the volts should be to the IAC, I wanted to bang a multimeter on the wires and test.
The J'rod
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Re: Idle on stock s3 304 ute

Post by The J'rod »

Although as in previous post as well, it is showing vacuum leak in 'items list' in tuner pro the rest a all clear in the list
The J'rod
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Re: Idle on stock s3 304 ute

Post by The J'rod »

are all clear in the list
immortality
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Re: Idle on stock s3 304 ute

Post by immortality »

I see you have a 70mm TB fitted in your other thread. You need to check that the butterfly, tps and IAC are all working correctly together.

When the engine is up to temp, make sure all the accessories are turned off then check to see that the IAC is sitting between 20-30 steps. Once that is achieved (by adjusting the butterfly stop screw) you need to check the TPS voltage is in the correct range. Sometimes when these TB's are over-bored the TPS voltage can be a bit low when the butterfly is closed to get the correct idle settings.
The J'rod
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Re: Idle on stock s3 304 ute

Post by The J'rod »

I did think that it could be the bored out throttle body so I put my old stock throttle body on at it still seemed to have the same issue but I might do it again just to make sure, and i will also run it through tuner pro and check steps on IAC and TPS voltage, vlad01 had also posted about checking steps on IAC, so its def somthing I need to look into.

Thanks immortality and vlad for all your advise i'm learning heaps.
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