lumpy idle

[ozzie01]

Just started car up at work and it instantly dropped to about 500rpm then when i touched throttle to build revs up it took about 5/6 seconds before revs raise.
There's no engine management light on so i just wondered iff anyone on here has experienced the same and could help me out with a diagnosis.
Cheers boys

 

[RobM]

Did it seem fine after this? Or did it continue to have a lumpy and uneven idle after this?

 

[ozzie01]

it ran fine after about 30/40 second it sounded like it was only running on 3 cylinders at first then ran fine all the way home( about 12mile) even at traffic lights at idle

 

[RobM]

I'd be fairly sure it was just 'one of those things' then. If it was something like a coil pack, which can have similar affects when one dies, then it would have carried on acting like that and would have felt very rough when driving.

It's probably more likely that you had a blockage somewhere that took a few seconds to clear. Keep an eye on it though, just in case it happens again as it's possible it is a faulty component somewhere showing signs that it's about to die, but that's fairly unlikely

 

[ozzie01]

okay cheers mate

 

[RobM]

If in doubt, find somebody nearby with VAG-COM and get them to scan for fault codes. If it was a component problem it should have logged a fault code.

Stick a post up in the VAG-COM help requests forum if you need to find somebody with it

 

[tompotts]

Quick question about start up idles...

Is it normal for the car to start and idle a bit higher than normal (im guessing it is, as it would be the automatic choke). But when it idles higher is it usually lumpy, as mine is reasonably lumpy on startup. After about 5 seconds the revs drop and sits pretty.

I was just wandering as im trying ot figure out if my coil packs are dying slowly on me.

Cheers guys

 

[RobM]

Higher revs is normal... can't say I've noticed the lumpy idle each time though?

 

[Number86]

It might seem lumpier simply because the revs are higher. Mine runs at about 12/1300 for 20 seconds or so, before gradually coming back down.

 

[tompotts]

Cheers guys,

Thats about the same as mine, but it tends to fluxuate from just above the marker to just below, when it settles back down it stops fluxuating.

 

[Number86]

Wouldn't worry about it then!

 

[tompotts]

Cool thanks guys, just thought it might have something to do with the fault my car keeps throwing.

 

[RobM]

What fault are you getting?

 

[LiCkWiD]

Yeh, mine is a bit similar. Revs high on first start, as you'd expect of an automatic choke. Then after 30 seconds or so, depending on ambient temperature etc. the car settles and purrs silently until I turn that kitten into a screaming piggy and welly it down the local by-pass.

(No lumpiness, though)

 

[tompotts]

What fault are you getting?

17544 - bank 1 lean, it comes up every so often, usually when ive been giving her stink and then let the revs drop below 15k. Just read around here before that the lumpy idle and this fault might point toward coil packs. Im still trying to decide whether its my maf or the coils on the way out.

cheers Rob

 

[RobM]

Have a look at this link: http://wiki.ross-tech.com/index.php/17544/P1136/004406

 

[tompotts]

Wicked thanks Rob.

Quick question here... If i wanted to check its not the maf, can i just unplug the lead to the maf and then run the car? And how long is it safe to do this for?

cheers again

 

[traumapat]

best to use as a test only as the engine will run rich and kill the cat.

when mine failed it drove well but was all over the place at idle. bloody mafs.

if your getting problems only when engines cold it may point to temp sensor but they usually show as a fault

 

[RobM]

Wicked thanks Rob.

Quick question here... If i wanted to check its not the maf, can i just unplug the lead to the maf and then run the car? And how long is it safe to do this for?

cheers again

Yes, you can. You can unplug the MAF and take the car for a drive to see how it feels. Don't think about performance too much here, as the car might feel slower... it's the smoothness that you're looking for. If the car is still lumpy and erratic with the MAF unplugged, you know it's not that. But if it's nice and smooth - even if it is a bit slower - then you might have found your problem.

As pat quite rightly says though, running with no MAF can make your car run rich so don't run it for too long like this. A few miles at a time wont hurt tough

 

[tompotts]

Wicked thanks guys, ill unplug it for the drive home tonight then. Its about 2 miles to the motorway, ill stop and plug it back in then.