Rough idle, stalling, fault code 2341

[Ross]

I took the RS2 out for it's maiden 'proper' drive this evening

The car feels great driving it around 2-3.5k rpm, it starts to run rough approaching idle and you get some popping from the exhaust. On idle it hunts 800-1000rpm with a constant slight popping - like a slight miss, but not on any particular cylinder. It stalls intermittently backing off to idle - hot or cold - and takes 10-15s after starting for the idle to rise from a lumpy 5-600rpm up to ~900rpm.

After a good drive to bed in piston rings I pulled codes and got 2341.

Any ideas? If it was consistent I'd have suspected unmetered air, if the MAF was knackered could it cause this code? The missing made me think bad earth on the coilpacks, again this seems good and it smooths out as soon as the revs rise. Not quite sure where I should start.

[QuattroFever]

Im having the same problem.....idle is "fairly" smooth but every 5-10seconds theres a little pop/stumble that I'm sure shouldn't be there and also getting stalling when coming down off the revs and hunting idle that sometimes goes up and stays at 1150rpm randomly and won't come down until it feels like it.

running on vems and 1.1.81 and latest vemstune.

so far...timing is spot on, I've changed coils to 034 HO, bosch f5dpor plugs and has siemens 630 deka's. All new.
Completeley removed IAC and blanked connections and opened up the throttle stop a little to see how it idles. Seems to have steadied the idle when it sits right but still sometimes decides it wants to idle at 1150.

changing coils and plugs didnt shift the idle misfire? if thats what it is? should the exhaust note be a perfect steady burble?

[A80Avant]

http://www.s2-audi.co.uk/tech_articles/motronic/ecu_faults.htm

2341 is related to fueling problems Ross, check those first i believe...

@ quattrofever: you will never get proper idle unless you use the ISV valve.

[Ross]

Thanks Vas, I did a search and found more results on the VAGcom code 00537, looks like it's either direct (fuel pressure) or incorrectly metered air (MAF dodgy / air leak sucking in unmetered air under vacuum) causing it to run lean. I had tried unplugging the ISV and Lambda sensor - runs the same in both scenario's - probably my next step is to try another MAF and pressure test the intake. If that fails I'll drive it up to MRC, want to get a healthcheck anyway as I will be running a little leaner with my stage #2 cylinder head flowing more efficiently.

I'll update this thread with results / progress.

[Ross]

He shoots.. he SCORES!

The car is now startin beautifully, iding sweet as a nut and begging to be driven.

Actually it was an easy find, I decided to check all the vac lines to the FPR in case something was causing it not to see manifold pressure - it was all fine - but what I did find is that the vac hose to the breather system had popped off, and that huge nipple under the IM was sucking in lots of air under vacuum. That explains why it was running fine with a bit of load - manifold pressure ~ = ambient but as soon as it was under vac it was rough again.

Some major hand contortion and a new jubilee clip later, job done and I'm happy as a pig in mud

[Sonic]

[QuattroFever]

http://www.s2-audi.co.uk/tech_articl...ecu_faults.htm

2341 is related to fueling problems Ross, check those first i believe...

@ quattrofever: you will never get proper idle unless you use the ISV valve.

it will idle fine without it as long as it is just idle so ok to remove as a test. Coming down off the rpms will be no good without it and under electrical load.

was just removing it incase it was the reason for the lumpy idle. will put it back now I know it's something else.

above post made me think of something...i'll try FPR would make sense too as its been starting rough lately too.

[S2central.net]

Unmetered air - well found and sorted. It's usually something stupid !