So, what seems like forever ago, we almost ran the audi completly out of gas. During the search for a gas stations we had a stumble, misfire and flashing CEL while changing highways (long uphill sweeper). At the time I attributed it to almost running dry as when we filled up a few miles later it was fine for the rest of the trip. However, it did have a couple more instances of misfire, until it finally disappeared after a couple days of me driving it.
Since then the car has been in limp mode and I havent been able to track down why (tho I havent spent alot of time yet either). There have been no more instances of misfires (verified with VAGCOM).
Cliffs:
Basically the whole ignition system is new from 18mo ago ish.
N75 has what I believe to be a normal coil resistance and the ports normally closed positions seem correct.
Idle vacuum is around 22-23inhg.
The PCV looks like its shot. You can blow through it easily in either direction (its as if the “valve” part of it is just gone. I tried just plugging the hole in the intake boot to see if that fixed things, but on a short trip there was no improvement.
Perhaps it would take more than a few miles to fix itself?
Thats about as far as I have taken the invesigation.
Is there anything I can check with vagcom to possibly figure out where the issue might be? Such as airflow at x rpm etc?
The stock intake boot is still orig as well (177k miles), perhaps it is getting sucked flat as I think someone mentioned to the last time I had an issue.
pinch the wastegate off, watch the gauge (CAREFULLY) and brake torque it just a little and see if you can force it to make boost, if it doesn’t go sky high in a quickness, sounds like the snail is toast. it probably needs an entire PCV system replacement while you’re at it.
anything rubber… elbow out of the oil separator, the T, the pcv that crams into said T, couple hoses that route to the back of the head, the elbow on the back of the head, it’s all full of nasty stuff, and then I’d remove the line from the turbo, remove the 8mm allen bolt at the banjo fitting and flush that with something caustic to clear it out. They can starve and kill the turbo so check it for restriction.
So my wife called me on her way home today. The boost is back on! I have no fn clue why really. I did put the orig N75 and bypass valve back in, and did a boost pressure test. Perhaps there was a loose clamp or something and I fixed a leak… ?? I did that on sunday so maybe it just took a few days to relearn? And maybee a boost leak would explian why it didnt make boost even with the WG hose pinched
Hopefully it stays good. I really dont wanna f with this thing right now. I will, however, get the new PCV stuff