'06 GTI - rough idle when cold. ok once warms up

[jkmelbs]

Hey guys, i've had my '06 polo gti for about 6-7 years with no probs. Had a $600 volkwerke service 4-5 months back with no mech/engine issues being identified

But on monday morning when i started it up for work it had the a very loud and rough idle (reving up). It was ok within a few min and the ubiquitous CEL came on

I'm not much of a car guy but a quick google showed it might be dirty throttle body or the MAF sensor. I did that test where you unplug the maf and see if the idle returns to normal (it didn't), meaning it isn't that.

Only thing i'd done differently is I fueled up @ with 91ron accidentally at that independent Puma station on albert rd in preston so i'm thinking maybe contaminated fuel has dirtied something up? - I'd been driving a diff older car and it as just automatic to put the 91. 3/4 of the tank too

it went ok for so long that I'd forgotten about it (it wouldve used up that tank on sunday). I've put in 98 yesterday morning and will keep topping up.

Plan is to grab some throttle body cleaner from SCA and give it a shot.

Does that sound about right or am I on the wrong track?

Cheers

[brad]

Scan first, diagnose, buy parts last

[Martin]

Agree with Brad - if you have a CEL scan it and find out what is distressing the ECU - it's a direct and definitive path to the problem

[jkmelbs]

i would except I dont have a scanner, nor ready access to one

[Umai Naa!!]

If you're heading to SCA, they can scan it with their Bosch diagnostic computer. I think they only charge a small fee.

They won't be able to tell you what's wrong, but they can tell you what the codes are, so you know where to start.

[h100vw]

Google the codes and don't clean the tb until you tell us what they are as well.

[jkmelbs]

thanks guys, didn't think of asking sca to scan it.
they were closed on the way home last night but i think they're open late on thurs so I'll stop by tonight

[jkmelbs]

Here's a pic of the scan: I only noticed just now that they'd put the wrong model in (1.4 polo instead of the 1.8T), not sure if the codes are different across these two models. If so then i'll go in tomorrow morning and get them to rescan it properly (i want my $14 worth!!)



codes are: 0214 & 063E

here's what it sounds like.
https://clyp.it/2xplkawq

if you listen til the end you'll notice how it goes back to normal after about 60sec. Can't really hear it, but there's an accompanying electronic click noise. It's as if it's trying to do something but times out, and it goes back to a 'default' setting. The recording was of this morning.

Interestingly this didn't happen on the drive home. Not sure if that's because it was a warm day or it was only sitting there for 5 hrs instead of 8, or if the ron98 has started clearing everything up. But it sure doesn't sound like an airbag problem

[h100vw]

Here's a pic of the scan: I only noticed just now that they'd put the wrong model in (1.4 polo instead of the 1.8T), not sure if the codes are different across these two models. If so then i'll go in tomorrow morning and get them to rescan it properly (i want my $14 worth!!)

[ATTACH=CONFIG]21643[/ATTACH]

codes are: 0214 & 063E

here's what it sounds like.
https://clyp.it/2xplkawq

if you listen til the end you'll notice how it goes back to normal after about 60sec. Can't really hear it, but there's an accompanying electronic click noise. It's as if it's trying to do something but times out, and it goes back to a 'default' setting. The recording was of this morning.

Interestingly this didn't happen on the drive home. Not sure if that's because it was a warm day or it was only sitting there for 5 hrs instead of 8, or if the ron98 has started clearing everything up. But it sure doesn't sound like an airbag problem

Neither of those faults is related to the engine.

I'd be looking for an airleak. A scan with VCDS would be better and check out measuring blocks 032 and 111. The fuel trims.

[jkmelbs]

Neither of those faults is related to the engine.

I'd be looking for an airleak. A scan with VCDS would be better and check out measuring blocks 032 and 111. The fuel trims.

Thanks for the tip! Good ear

i was running my hand along the hoses and this happened:

if you look at the hose next to it you might see some black tape around it. I guess it's been like that since i'd bought it (6yrs ago), but neither I nor service workshops noticed.
When taking the tape off to see if that hose was busted as well (it was), the hose snapped in another spot.

I did a quick diy with some tape that should last me another 6 years (joke) but obviously they need replacing. I've done a quick google for replacement vacuum hoses but haven't had any luck. Do you happen to know what these are these called exactly and/or a link to some replacements? As I said, i'm not much of a car person but I was able to take both these hoses off so replacements should be just plug and play

The CEL and rough idle was gone when i started it up after putting the taped up hoses back in.

cheers

[Umai Naa!!]

They're for the SAI pump.

[jkmelbs]

They're for the SAI pump.

cheers, that narrows it down.. happen to know a part number? still having trouble googling a replacement.

[h100vw]

I'd say delete the sai pump and have the fault code written out in the tune. Probably won't be long before the combination valve or pump fails, which costs a small fortune to fix. Bonus 50 hp with the flash as well.

[h100vw]

Audi, Volkswagen, Skoda, Seat Parts Catalog (Teile Katalog) online BMW Ersatzteile for the part number