judders when idling

[stan]

My 99MY s4 judders noticably when it's idling. The engine revs are stable but the whole car shakes gently. Is that normal ? I haven't noticed it on any other car I've driven.

By the way it's not modified as far as I know.

Stan

[wazza]

Hi Stan, welcome to RS246 [img]images/graemlins/laugh.gif[/img]

I presume by the fact you are using the word 'judder' it is very noticable. i.e. not just a vibration.
I've not heard about this before, especially as the revs are steady [img]images/graemlins/crazy.gif[/img]

[Nige_RS4]

Stan, this is definately not the norm for S4's - I would suspect a worn/broken engine mount ???

Nige.

[toasty]

Have you tried reading the fault codes? Could be a dodgy spark plug or coilpack, or faulty injector.

[Joshie]

It could also be an air leak or a faulty MAF. Mine was doing this the other day on tickover and I know my MAF was faulty and I also had an air leak.

If you don't have an on board diagnostic plug (OBDII / VAG com) get it into an Audi dealer and ask them if there are any codes showing. The codes will help diagnise the problem.

[wazza]

Joshie, would this not give an unsteady rev counter reading though?

[Dippy]

Hi Stan,

There are a few people on this forum who are from Reading so if you need any direct help just ask.

However as has been said, if your revs are constant and the car shakes, then it is unlikely to be an engine control problem but an engine mount problem.

I can certainly agree that it is not normal, so you need it checked out (by anyone except Audi Reading of course).

[DJG]

Hi another Reading person here.

Have never noticed any juddering at idle on my 99.1 S4

If you increase the revs slightly does the juddering go away.

Few people have had problems with the exhaust heat shield vibrating. I'm not sure at what engine revs this occurs.

[img]images/graemlins/beerchug.gif[/img]

David

[Golich]

It's not normal on my S4 either.

I'd go with Dippy's theory as a first guess because it's relatively easy to check yourself if you have a jack / ramps etc. BE CAREFULL!!

But it could equally be one or two cylinders down for any number of reasons and still maintain a steady enough rpm as far as rev counter readings are concerned. Had that on a capri V6 when the leads were on the wrong way!

However, any engine problem should be obvious as you should notice a lack in acceleration and the engine won't sound right especially if you get someone to drive the car away from you. I've had experience of this. The engine sounded fine from under the hood but when the guy drove away it was blatently obvious it was missfiring. VAG COM would help.

Can't say I've tried to see the engine/gearbox mounts without the splash gaurd removed. I'm 99.9% sure you can see the two gearbox mounts either side of the gearbox. The front snub mount is definitely not visible from underneath without removing the splash gaurd and since it is right at the bottom of the engine to front cross member. I doubt you will be able to see it properly from above. But the splash gaurd is easy to remove.

I don't have the engine manual with me to determine where the other engine/gearbox mountings are located.

But I can look it out if your stuck.

[Joshie]

Joshie, would this not give an unsteady rev counter reading though?

Well perhaps - it's just that as I stood at the exhaust end of mine and listened to the tickover it was not a steady burble but almost a slight misfire which I took to be a judder.

Needs to get it to a garage though - difficult to diagnose it from a PC

[stan]

Thanks all.

I had it checked out at Martins Audi Basingstoke about 4 weeks ago when it was in for some other warranty work (new power steering pump). I specifically asked them to check the dump valves and they stated that they couldn't find a problem.

It is more like a constant light vibration. When you sit in the car you can see the gear lever vibrating. I did wonder whether it was something to do with the engine mounts. Performance wise it seems to doing okay.

I've just moved to Guildford. Are Guildford Audi any good? If so then I'll book it in for them to have a look. It's under Audi warranty so then can replace what they like as long as it doesn't cost me.

Stan

[JohnW]

Well,

you have Guildford Audi on the Slyfield industrial estate.
There is also a VAG specialist on the same ind.estate that some VW owners I know have used, and they all rate this place. Sorry but I can't recall their name at present.

Apart from that the next nearest main dealers are in Walton on Thames, Farnborough, or Horsham.

What I did when I moved was to pick up the yellow pages and have a scan of the car dealers section.

I've not found any other places that people recommend.
BTW I'm new to Audis (always had VWs previously, all serviced by Colbornes who are now on Slyfield too) so have no real experience of what these places are like.

Cheers,
John.

[Dippy]

It is more like a constant light vibration. When you sit in the car you can see the gear lever vibrating. I did wonder whether it was something to do with the engine mounts. Performance wise it seems to doing okay.

Last night I had a good blast to a friend's house and was just letting the car idle for a minute to cool when I did notice the car very lightly vibrate. However I did not see the gear knob vibrate, and I have very stiff suspension so I would expect my car to shake more than most.

As you say, Audi are paying for faults so let them sort it.