630-Audi

1.8T, tip, APR v3, forge bpv

Symptoms: Car is overboosting. When getting on the gas (in drive), the boost hits about 1.25 bar and starts to misfire. Throws CEL (Cyl 1 misfire, Multiple misfire codes). Goes into soft limp mode for awhile (limits at .5 bar) until I completely back off the gas, then I get get it to overboost again.

I checked the vac hoses between the N75 and turbo and they seem fine. I also checked all the hoses around the N249, the L hose, and the hoses around there. The wastegate rod doesn't move, so it's not broken. While checking for broken hoses, I did find a coolant leak, but nothing to do with vac.

If the wastegate was stuck closed, or my N75 was bad, I would be boosting like crazy as the RPM's climb, even in park. Sounds like I can eliminate a bad wastegate, bad N75, or the hoses around it, correct?

My N249 isn't bad, because I can hear my BPV opening. I would think that if it was bad, I wouldn't hear it opening at all...

There's a check valve that looks like it's starting to melt, but it doesn't look like it's leaking yet.

I'm going to log blocks 114, 115 and 003. I tried to do it today but my laptop battery died.

Any other suggestions???

bitjockey (bum)

You won't boost in park, there's no load on the motor.

RKA

1.25 bar seems acceptable. So I would deal with the misfire for now. How does the plug look? Have you swapped coilpacks yet?

Stratocaster1422

i'm having the same issue and the misfires follow the coil pack, so i'm replacing the bad one.

630-Audi

the old plugs still looked good.

you bring up a good point. IIRC, before I changed plugs I think the misfire was on #4, now it's on #1. I swapped the order of the coil packs randomly.

I'll use vagcom and count the misfires, rotate coil packs and see what happens.

tx!

630-Audi

even if wastegate was stuck shut?

bitjockey (bum)

the motor needs load to make boost.