Rough engine interittently.

[LondonThing]

Hi All,

Hoping someone here can shed some light on whats wrong with my car.

Have an a4 tfsii2.0 quattro, 56 plate. Long story short, we had our coil packs replaced on the recall thing Audi done 2months ago. About a month after the replacement the car runs rough on start up intermittently then possibly clears after a 5min run or stays for longer. It sounds like it has a miss and feels like a lack of boost, limp mode? No warning light. This can happen at anytime when hot or cold and can clear at anytime. I've done a small service on it since, swopped plugs/oils/filters as I was going to anyway. However, problem still exists and I thought I'd got a bad coil pack, my vagcom wont show me the memory. So the wife takes it back to the audi garage today and the mechanic had given me a print out of the events.

08891 P2261 008
Turbo Boost Pressure not detected mechanical intermittent

01287 p0507 001
Idle Control System
rpm higher than expected
intermittent

085583 P2187 004
System to lean at idle, bank 1
Intermittent

01089 P0441 002
Evap Emission contr.sys incorrect
purge flow
intermittent

01602 P0642 002
sensor reference voltage "A"p3137 001
Circuit low
Intermittent

12599 P3137 001
Intake manifold runner control (IMRC)
Basic settings not carried out
Intermittent

08825 P2279 002
Intake Air system Leak
Intermittent

Now ideally I'd like to clear these but my vagcom isn't working at the moment. Just to see what would come back and to diagnose. I know seeing another thread that the evap problem has been resolved by replacing the n80 valve. However this thread didnt have the turbo boost fault. The mechanic advised the wife it might be a valve or something on the turbo. I need to confirm what part the mechanic mens but thought I'd pass it by here if anybody can add anything.

Any info would be great.

Thanks All.

[gblades]

See http://www.golfmkv.com/forums/showthread.php?t=24952
I think the mechanic was referring to the turbo diverter valve.

[LondonThing]

Thanks Gblade, I did see that after posting & does sound like what the wife had been told. Althought the mechanic said he couldn't confirm if replacing would resolve this problem. Will trawl posts to see if anyone suffers the same symptoms I do with the above problem.

If anyone has experienced the turbo divertor valve problem with a 2.0tfsi, would it really feel like a miss & lose boost. My engine runs really lumpy when it's having the problem and feels like a slight missfire with no boost, just don't think this is a turbo problem. If it was this and a tear in the diaphragm, wouldn't it be a problem all the time? Unless this turbo divertor failing has knock on effects and can be sporadic problem?

Thanks again Gblade, I can't really afford to get this resolved by audi so any more thoughts on would be great.

Cheers,

Thing

[warp_speed]

yes, they can be a problem, they use a diaphragm seal which can perish over time and split, this causes pressure to escape giving crappy running. Its easy to change and can be accessed from underneath the turbo, cost around £55 and takes around 10 minutes to change.

[LondonThing]

Thanks warp_speed, will probably go ahead and source one I reckons. Would be nice to confirm this valve could cause this problem intermittently as well. Sounds like I'll take it apart and physically inspect it. The odd thing is that this sometimes happens when I restart the engine warm or sometimes when it is cold. Maybe it just gets stuck or some other problem related with it. Thanks again Warp_speed....

[James05]

Hello,

Mine went a while back and what you describe sounds exactly the symptoms I experienced.

[LondonThing]

UPDATE: Still need help I'm afraid
Well I got around to replacing the divertor valve the weekend, not something I'd want to do again off a jack. The one I took out 'orange diaphragm' version was in pretty good nick. No real signs of damage, diaphragm was intact and no signs of leakage around where it connected, if I would see any? Although noticed a small amount of oil on it, turbo seal gone, not loads just a coating on the one corner? Anyway, noted the old divertor was more of a dampered action from the new updated version I put in, which has a more on/off action with nothing inbetween when compressing. Took the car for a hard drive and thought all was good, better response from the turbo etc then suddenly tappety tap and feeling lumpy again. Not sure where to go now??? Could this be down to a cam tensioner or something like that or even worse a sticky valve? I can't really afford spending mass amounts of loot getting this into Audi to diagnose.

Any more ideas welcome..

Best,

Thing

[warp_speed]

Another thing to check is the crankcase ventilation valve (PCV), its another thing which can give poor running. I believe there are two of them, the easiest and most likely to go wrong is the one on the top of the crankcase. Its around £20 and another 5 minutes to change that one, the one on my 2.0T was a version C, I believe the new one is something like a P, so its a source of problems. There is a seal that goes with it, you might as well get a new one while your changing it, think its another £5. Make sure they order the correct valve for your car.

[LondonThing]

Thanks Warpspeed,

Will look into the pcv's.... Ideally need to get my vagcom sorted and try to clear the events and monitor closer. Do you think it's worth me swopping the cam follower also? I know ideally need the logs to check but thinking low cost things to try and resolve at this stage.

Thanks

Thing

[warp_speed]

Thanks Warpspeed,

Will look into the pcv's.... Ideally need to get my vagcom sorted and try to clear the events and monitor closer. Do you think it's worth me swopping the cam follower also? I know ideally need the logs to check but thinking low cost things to try and resolve at this stage.

Thanks

Thing

Are you talking about the cam follower in the petrol pump? I'm not sure if that would give poor running, unless it was at high speed. But I'm not an expert in that sense, maybe someone else could give advice. But I know that a dodgy PCV valve will give poor idling.

The DV and PCV were the things I changed on my car because they were cheapish and are potential issues with the 2.0T. In my case I changed the PCV valve first because my idling was not as smooth as expected and oil was starting to leak around the oil cap. The DV was changed because I wasn't sure if it would be a problem, but I can now reach the limiter whereas before I couldn't, so unless it was DV or PCV, who knows.