Volkswagen Golf III (1992 - 1997) - 1994 1.8 auto: idling too fast

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Tue 20 May 2008 16:04
1994 1.8 auto: idling too fast - Lud
Iraqi pal drove me last night in gf's car, a 94 Golf CL auto. The car goes perfectly well but the idle speed in N or P was above 1000 rpm at all times, usually between 1100 and 1400. Without knowing specifically what the idle speed should be, I thought this was on the high side, and of course the variation seemed to indicate some sort of fault. He says the car is quite thirsty, but again no figures. Although a perfectly sensible driver well used to London, he surprised me by asking what the rev counter was. I seem to remember his BMW 520 auto had one too.

Is it possible that this high and variable idle is caused by mechanical stickiness in the main inlet butterfly rather than some engine management glitch? If so, might it be amenable to a bit of oil and rattling the butterfly back and forth a few times? I feel that my friend and his gf may not be too good at judging a garage, and the VW specialist I recommend is in Kilburn, while they live beyond Richmond. Does anyone have any ideas about this? Informed comment gratefully received.

Edited by Dynamic Dave on 20/05/2008 at 19:46

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Tue 20 May 2008 16:12
1994 1.8 L reg 1800 auto: idling too fast - Screwloose

Idling too fast and drinking fuel? I'd wonder about the coolant temp sensor.
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Tue 20 May 2008 17:14
1994 1.8 L reg 1800 auto: idling too fast - Lud
The engine cooling fan was on when we got out of the car after half an hour through traffic, but then it might be anyway, especially with the idle too fast. Do you mean the fan is cutting in too soon and making the engine run cool, therefore enriched?

I will pass that on, but I'm afraid he might get it wrong when talking to the 'very nice old man' who runs the local independent they go to...

Thanks Screwloose.

Edited by Lud on 20/05/2008 at 17:15

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Tue 20 May 2008 21:25
1994 1.8 L reg 1800 auto: idling too fast - Screwloose
Lud

If the ECT sensor is FUBAR; then the ECU reads it as -30C and maintains a warm-up fast idle and rich mixture even when the engine is hot.

The fan switch is a separate unit and probably just responding to the fast idle producing excess heat.
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Wed 21 May 2008 15:54
1994 1.8 L reg 1800 auto: idling too fast - Lud
What does FUBAR mean Screwloose? Is it a fault code, and should a decent independent (but not VW specialist) have a device for reading it?

Where is the sensor?

Edited by Lud on 21/05/2008 at 15:55

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Wed 21 May 2008 16:00
1994 1.8 L reg 1800 auto: idling too fast - Screwloose

It's a military acronym meaning "severely broken....."

The 4-wire coolant temp sensor is in the water housing where the top hose meets the front of the head - held in with a U-clip.

If replacing it; get a new rubber seat and clip. It just pushes in.
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Wed 21 May 2008 16:47
1994 1.8 L reg 1800 auto: idling too fast - Lud
Thanks very much Screwloose. I will pass that all on.
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