Idle Adjustment On 2.1 Fuel Injection

[timthemod]

Engine is running too fast on idle. Is it easy to adjust? And if so how?

Thanks

[KINGPRAWN]

Great big flat screw on top of the throttle body... Simple as.. In for slow and out for fast. But if its just got faster recently could be an air leak or cable issue???

[California Dreamin]

You need to be aware that the idle stabilising unit needs disconnecting whilst you carry out your 'Hot' idle adjustments otherwise it will compensate and give you a false idle.
The GOAL....is to get to a 'HOT IDLE' point where re-connecting the idle stabilisation makes NO difference (ie: in it's resting position).

Martin

[timthemod]

Thanks guys

[timski]

You need to be aware that the idle stabilising unit needs disconnecting whilst you carry out your 'Hot' idle adjustments otherwise it will compensate and give you a false idle.
The GOAL....is to get to a 'HOT IDLE' point where re-connecting the idle stabilisation makes NO difference (ie: in it's resting position).

Martin

You need to be aware that the idle stabilising unit needs disconnecting whilst you carry out your 'Hot' idle adjustments otherwise it will compensate and give you a false idle.
The GOAL....is to get to a 'HOT IDLE' point where re-connecting the idle stabilisation makes NO difference (ie: in it's resting position).

Martin

Sorry to highjack your post Tim, but Martin's post has got me thinking. I am struggling with an erratic idle speed at the moment. It keeps reving high then low and then back high again etc. I am cleaning and remaking all the electrical connections at the moment hoping that might be the problem. I'm guessing the problem could be a faulty ISCU? Could I use the above method to check whether the problem is caused by the ISCU, i.e. disconnect the ISCU once the engine is up to temperature and see if it runs smoothly with it disconnected? Or am I barking up the wrong tree?

Cheers,
Tim.

[nicq]

When you unplug the unit you should plug the 2 connectors into each other before adjusting.
Nic

[timski]

When you unplug the unit you should plug the 2 connectors into each other before adjusting.
Nic

So could I get the engine is up to temperature, turn her off, disconnect the ISCU, connect the two wires together, start her up again and then see if it runs smoothly? Would that then confirm the problem is a faulty ISCU?

Cheers,
Tim.

[California Dreamin]

So could I get the engine is up to temperature, turn her off, disconnect the ISCU, connect the two wires together, start her up again and then see if it runs smoothly? Would that then confirm the problem is a faulty ISCU?

Absolutely.....the idle stabilisation unit is effectively redundant at idle with a engine up to temperature. It's purpose is to compensate for load, warm up cycle and lean burn overun (turning on the lights, using the power steering, if the vehicle has it, cold start and the lean mixture that you get coming off a motorway etc).

Martin

[timthemod]

Looks like a faulty idle control unit, my garage did some tests, works only intermittently, apparently they are about £80 new :O

Firstly can I fit it myself,

secondly is it worth getting a second hand one?

[California Dreamin]

Yes/Yes......5 minute job and worth the gamble as a second hand one should be under £15.

Martin

[slowcoach]

just to piggy back this thread- ive a 1.9 DH with injection. My idle, once up to temp, has a slight rhythmical warble.. every 8 seconds , the revs dip for 1 second, and then return. it never conks out. this only happens once upto temp, but it always occurs. it has done this for 4 years since i got it, and doesn't seem to affect anything.

if anything, my idle at full temp probably runs a little high, just going by ear. as it hasn't been a problem, ive not investigated. its been sniff tested and tuned for mixture a couple of years ago, and runs well.
any thoughts? ill try the above idle unit disconnect and see if that changes anything too. cheers!

[AdrianC]

Looks like a faulty idle control unit, my garage did some tests, works only intermittently, apparently they are about £80 new :O

Firstly can I fit it myself,

Dead easy. The idle control ECU lives behind the RH tail light - you can either go in from the light or from the engine bay, by taking the air filter and plastic blanking panel out.

secondly is it worth getting a second hand one?

If it's a working one or you can get your money back if it doesn't. Might be worth trying a known-good first? If you were closer, you could cheerfully borrow ours. Check also that the idle control circuitry is being brought into play - the throttle cable and switch on ours were out of adjustment, so the switch wasn't closing, and the box didn't know that it should have been controlling the idle.

With the engine off, just flick the throttle open and closed a few times inside the engine bay - you should hear a click from the switch. If you've got a multimeter (if you haven't, get one), then just check for continuity between the two pins of the multiplug, by the rear right inlet manifold runner. It should reliably and consistently close (IIRC) when the throttle's shut and open as soon as you move it, whether you snap it shut or ease it shut.

[slowcoach]

just to piggy back this thread- ive a 1.9 DH with injection. My idle, once up to temp, has a slight rhythmical warble.. every 8 seconds , the revs dip for 1 second, and then return. it never conks out. this only happens once upto temp, but it always occurs. it has done this for 4 years since i got it, and doesn't seem to affect anything.

if anything, my idle at full temp probably runs a little high, just going by ear. as it hasn't been a problem, ive not investigated. its been sniff tested and tuned for mixture a couple of years ago, and runs well.
any thoughts? ill try the above idle unit disconnect and see if that changes anything too. cheers!

Just got in from correcting this specific issue described here- as said in this thread, engine up to temp, disconnect idle module and connected the plugs together. One and a half turns in for mine on the idle screw has stopped my high and rhythmically challenged idle. Result! Love it when things are simple. Didn't even get ma fingers dirty . . . thanks everyone

[timski]

Just fixed mine too. I finally got round to cleaning and remaking all the connections in the engine bay and the last one I came to was the ISSU. I was gonna try the test you suggested but noticed it was sitting in a pool of water behind the tail light. Dried it, cleaned it with WD40 and popped it back in and now it is running well.

I'm guessing the ISSU used to be screwed against the wall of the engine bay behind the tail light as it looks like there are some old fixtures there. When it was LPG'd they put some of the LPG system gubbings behind the tail light, so probably removed it from it's fixtures and left it lying on bottom of that area behind the tail light where water is pooling. Will figure out some way of raising it up off the bottom and see if I can figure out where the pool of water is coming from. I'm guessing it might have come down the side vent when I was jet washing it?

Anyway, I'm relieved I didn't have to go to the auto-electrician in the end.
Thanks again,
Tim.