vorlockfoss

Hi all, how are you?
I have an issue that I think is the PCV...
Over the last few weeks I've had issues with intermittent stalling, usually when the revs are slowing & I'm still moving. I've had fairly intermittent issues while starting the engine, in that it sometimes wouldn't start (coughs & splutters) without giving it a few revs. I initially thought that was related to stop/start being on when I parked & turned the engine off, but it then spluttered when I tried to start it even though the stop start had been off. Anyway, after all this getting gradually worse, last night the engine started intermittently spluttering while driving, just for moments, on and off for around 4 hours. Come to think of it, there have been several moments over recent weeks where its 'spluttered' and the EPC light came on, but was fine after stopping & starting... Back to last night; the time between splutters/noticable lack of power grew shorter and then, as I pulled in to a car park it coughed, tried to die, and then did. I managed to get it running again, with difficulty starting, and it ran like a bag of heavy spanners, but did get a little better after a couple of minutes. If I reved it, there was a sweet spot between 2 & 3,000 revs where it sounded almost normal. On idle it sounded like it was running either on 3 cyclinders or missfiring on all 4. This morning I checked the plugs & Coils & they're all fine (I have new spares that I use for this). All 4 plugs were sooty, the one nearest the bulkhead a little more than the others & they appear to be running a little lean, but I could be wrong about the lean bit. I've had a cam sensor error code issue for a few weeks & we thought it was the chain, but the mechanic checked & thats fine... He did clear some carbon/sludge build up out of the variable timing oil pressure thingamybob at the front & it ran so much better. He mentioned the oil gause was missing, but I can't see that being too much of an immediate issue; I suspect that was removed when I had the chain changed around 3.5 years ago. Anyway... I can't think of anything else at the moment.
Thanks,
Paul.

Viper22

I'm new to all of this, so I will just mention common things I have discovered when doing research for myself. The first thing I thought of was carbon build up on the valves. Since these engines are direct injection, there isn't any fuel hitting the valves, to clean them like in other none direct injection engines. So perhaps it's time for a carbon cleaning of the valves. Depending on your mechanical ability, this may or may not be an easy job for you. Other things you may want to look into or ask your mechanic about is the fuel pump, perhaps you're having issues with the fuel pump not sending a constant, reliable flow to the injectors. You may have clog injectors or possibly managed to get a tank of bad fuel. Again, i'm new to Audi, so i'm not 100% sure of your issue. I'm just throwing ideas out from trouble shooting past vehicles. I'm sure someone with a better knowledge base will chime in soon, at least I hope they do.

vorlockfoss

Hi Viper22,

Apologies for the VERY late reply...

A lot has happened since my original post. The PCV Valve had certainly failed, as had the Balance Shaft Chain and the Cambridge. I have replaced many parts on my road to investigation. They include the N40 Valve (is it a valve?), the Water Pump, the Solenoid Valve and Magnet, the Cambridge & Exhaust Bolt, the 2 main Timing Chains (not oil) & Runners, the Timing Tensioner, the Crank Cogs & Bolt, the Camshaft Sensor, the Low Oil Pressure Sensor, the Throttle Body, the Spark Plugs, the Coils, the PCV Valve and the Crank Cog because the Balance Shaft Chain was actually hanging off...! I think that's it. I've also used a little Sea Foam to try & de-carbon (you should have see the cloud!). I also had another issue where when I turned the heater on I got a low oil pressure warning, which makes noooo sense. Turns out it was my fault, as I'd tried to install a reverse camera & tapping the reverse light feed was causing an issue on the Canbus that caused the sensor to falsely report low pressure; well, that's what I've concluded now that I've installed a dedicated relay for the camera & the low pressure warning has gone... (I hope).

Anyway, a bit of a list.

Oh yes, I will have to change the Camshafts at some point as the bridge mesh came off in 2019, which was caused by the PCV Valve failing, which caused all the problems I've had. I've changed the Cambridge twice in the last 6 months because the mesh caused grooves in the end of the shafts & they transfer eventually to the Bridge, which affects the oil flow...

Thanks for reading my speech, but I just hope it may help others.

Paul.