Possible PCV failure - P2279, P2187, P0507, C1555

[kt883]

I have a 2010 A4 2.0T and Just finished doing the WG replacement as car was running great for about a week holding 12psi, peaking a bit more.

So Sunday I start car up, runs fine. I creep out of my neighborhood and get about 10 mins away when I notice My idle is abnormally high, like 1100rpm, when it should have settled by now. I notice its rough like a misfire so I accelerate off the line and get a flashing CEL and I now hear a whistling noise which sounds like air squeaking by thin rubber like a balloon so I’m thinking PCV is bad.



I took the oil cap off and there is suction pulling the cap back down and also on the hole in the pcv there is suction as well there.
My car currently has the PCV valve with the clear portion (no "XX" letter suffix). Going to replace it but which revision should my car have as I’ve read conflicting stories that black is the update one. When I called Audi previously about my pcv they said “oh your car already has the updated one – it came in for pcv service before”

Later that day I swapped cyl 4 coil around cleared codes and started car and it now runs worse, to the point of nearly stalling and codes read misfire on all cyl/random misfire. I checked to ensure the harness was clicked in and it is. Could PCV cause Random cyl misfires?

I did notice that there is a bit of oil in 2 of the cylinders. There is not a lot so possible that the pcv broke and did that in the short time it was run.

As an aside plugs were changed 30k ago and car has original coils (only changed one so far to newer all silver style oem – others are black oem)


This is after I cleared all codes and started it up after examining coils



Car currently has Beige PCV and parts guy says I need one ending in AE. He doesn't know about reflash and crank case seal service department is busy so I cant ask if that's been done on mine

EDIT:
I installed the new PCV. My old one was beige but had no suffix where as the new one is also beige but has suffix AE. It eliminated the squeal but It did not help the problem, still suction on oil cap. I do notice there is oil leaking from front of engine as I can see when underneath the car flowing down onto oil pan from above dripping onto belly pan , no apparent oil leak at rear. I see that my front most belly pan has accumulation on it and I just cleaned it 2 months ago (thought nothing of it figured mess from oil change or top up.) I'm guessing the pcv caused the front crank shaft seal to be blown out? If so how involved is this repair? What's involved in it?

[MacFady]

I did notice that there is a bit of oil in 2 of the cylinders. There is not a lot so possible that the pcv broke and did that in the short time it was run.

When was the valve cover gasket changed last?

[kt883]

It has not been changed to my knowledge but last summer I had tensioner failure so had chain done then at Porsche certified mechanic. Would that involve removal of VC?

[S4'ed]

Why don't you replace the failed PCV unit. Yes, if the diaphragm ruptured, which it sounds like it did, this can cause misfires due to lean AF ratio, because of the unmetered air.

Replace the PCV as soon as possible...running the engine with the high vacuum in the crankcase can pull your rear main crankshaft seal off its mounting plate...causing a $1200 repair (need to pull the transmission out of the car to change this $40 seal)

And you oil leak into the spark-plug holes is due to a bad gasket on the valve cover, but the bad PCV, which allows a greater than normal vacuum in the crankcase & under the valve cover would actually stop is from leaking there......the bad PCV is not the cause of the leak.

[kt883]

I replaced the pcv with new version dealer recommended for my car which was beige just like the one I previously had but no change. Still have suction at oil cap.

Currently in shop doing smoke test. They found broken dipstick tube (not sure how its broken when I never touch it - used only for oil suction by mechanic)

They will be replacing that and looking into some other oil leaks they found

[S4'ed]

It is normal to have a slight suction a the oil cap.

[van462]

If it idles good and goes to hell when you apply throttle look over your boost lines. With the wastegate tweeked you may have spiked pressure and popped off a hose. Removing the fog light plates allows easy inspection of the intercooler connections. The MAF won't see air moving across to increase the fuel as RPM rise.
If its an idle problem to rule out engine air leaks, disconnect the hose from the intake manifold to the PCV. Block off the intake manifold with a thick ziplock bag and secure with a ziptie, hose clamp or tape. Remove the oil fill cap and start. The oil cap off is to vent crankcase pressure.If it idles good like this and revs ok you are leaking air into the block somewhere.
Also look on the back of the intake manifold where an arm connects to the movable vanes inside. The arm goes thru a plug that is known to pop out and cause an intake manifold leak.

[kt883]

The night before I did notice a boost spike at full throttle so you may be right Van

It's at the shop now as I didn't have time to play with it. Seems like they are fixing small problems I could have tackled myself in order to narrow down possible causes. I would have preferred to do oil dip stick and valve cover (if they do that) myself

[kt883]

Brought it to shop they fixed the oil leak and the car runs a bit better. They say the smoke test revealed leak near transmission meaning likely rear main seal but there is no oil leak visible.

At this point car is drivable and has normal power unless CEL is on it just idles weird/rough and idle jumps a bit sometimes

[kt883]

I called dealer to see if I need a reflash for the new pcv he says no and he's never heard of needing one. Not sure if they are understanding me? I Put in a PCV with Suffix AE so can anyone confirm if I need the reflash?

How involved is front crank seal to go along with it?

[S4'ed]

Typical clue-less dealer.....

I bet when your PCV was bad, the resulting excessive vacuum in the crankcase pulled the rear main crankshaft seal off of its mounting plate, which is now causing your excessive idle air leak problem. A bad front crankshaft seal can also cause an excessive idle air leak.

Changing the front crank seal (and lower timing chain cover) is a relatively small job compared to dropping the transmission to replace the rear crank seal. When they do the front seal/cover, there is some risk that they screw-up the cam timing when the crank pulley is removed...which can grenade your motor if the timing chain slips a few teeth....

[kt883]

I'm going to call another dealer and see what they say.

I had timing chain service last summer from broken tensioner so is it possible the front crank shaft seal was done at that time? Just trying to prioritize what I am fixing as The RMS is up next but don't want to do it if I'm in danger of blowing it again because of not getting software update or some other part.