mate, the idle issue can be down to several things:

First port of call would be to check out the MAF. Seeing as you have vag-com you could log the airflow and see where it peaks, and see how the graph looks.

Coolant temperature sender is another one, although would have thought that this would give error codes.

Get the throttle body cleaned - coking up can lead to a rough idle.

Are you still running the standard DV? This can also be a problem as it might be leaking/sticking - recommend changing to aftermarket Forge 007P version.

I dont know much about the N249 valve, but believe it controls the DV. I am sure searching on this forum, or even contacting westec performance or another company on the forum will bring prices up for the N249.

If its still in warranty - get it back to the dealer. I had ALL of the above (bar n249) changed/cleaned before anything got better.

By the way, ALL 1.8T's sound and run like a diesel on startup. After about 1minute, they settle down as the revs drop. This is normal.

AFAIK, most 1.8T (or at least the people i talk to) have the idle issue, only not quite so bad as you mention. These engines are known to idle roughly - I found changing to optimax or BP ultimate fuel helped LOADS, and Morrissions fuel is total cr*p.

On a side note, my revo installation/exhaust fitting seems to have helped with the idle issue too!

Hope this gives you a bit of help mate.

 

Sounds good because i have had exactly the same problems with my motor thanks Pabs

 

Craig, not sure about your second question - someone on here or your local stealers could tell you what components would cause the lean running etc.

For the first issue, I had EXACTLY the same problem.. remove the T.B and clean with air-intake cleaner (or carb. cleaner), tissues, cotton-tips and thin paper strips - the problem is dirt sitting between the valve-flap and T.B wall..
For precise instructions see here.

Cleaning the TB is a good place to start as it costs nothing other than 15-30 mins of your time!

Good luck mate

 

try this link for bypassing the N249 valve.

http://www.sportcompactracing.com/vbulletin/t27262-.html

let me know if it works

 

Craig,

do you or have you run an atmospheric dump valve on the car? Because the fault code with the N249 "complete mechanical malfunction" is exactly the same one i get logged if I put my HKS BOV instead of a recirc one.

For your second fault code, it could be that one of the lambda sensors has picked up a slightly lean mix at some point, although this code has been picked up when a MAF is on its way out. IIRC a MAF on a standard car should read a peak of 140-150g/s in VAG-COM...

I remember you had this fault code when you had the MBC installed - did you clear the code at the time? i.e. do you have a full version of VAG-COM or can you just see the fault codes?

Try resetting the fault codes, and then unplug the MAF to see if it helps with the running. I'd also recommend cleaning the throttle body as mentioned above.

 

Craig,
I'd also recommend cleaning the throttle body as mentioned above.

I wonder where I got that advice from?
**Cough-cough**

 

I wonder where I got that advice from?
**Cough-cough**

lol! Hope its still running sweetly mate

 

lol! Hope its still running sweetly mate

Yes thanks mate - more power it seems too... crumbs! (that drink is STILL there )

Cupcrag Let us know how things are once you've cleaned that T.B mate

 

Bank 1 usually relates to the Lambda probe.
Bank 1 is before cat and Bank 2 is after the cat.
That could be the problem with it being lean as this will adjust the mixture.

 

Thanks for all your help guys. I will give the car a full clean at the points mention. I do have a BOV fitted but the N249 code has only come since the MBC was fitted and taken off. Then all these code croped up. Its the fuel one I am more concerned about as running lean isn't good for the engine as i have heard. The temperature sensor is showing a fault at the moment as well under the instruments sectionof VAG-COM. Temperature sensor, short to B+ Intermitent. Couuld this the problem with idling??

Cheers guys

 

yeh, that problem sounds like its relating to the coolant temp sender/sensor.