1G: Rough Choppy Idle Surge and Spiking on Boost gauge

[Rajin]

Hey guys, I know this has probably been beat to death, but I'm needing some second ideas.

My friend bought a fairly nice 1GA TSi AWD a few days back and after I checked it over and found it has some weak (Ebay) boost controlled, decided to route it correctly, it ran fine afterwards.

A few days later he contacts me saying a plugwire popped mildly up and the car now idles like a truck or a car with a dead cylinder, misfire situation. The plug popping up leads me to believe maybe a bad coil or wire? I have inspected and changed the plugs, 2 were burning black and 2 were running white.

And ideas, also getting a correct MBC on it soon, to rid the ebay one.

[WES_393]

To start, just run the boost source right to the wastegate. That will keep the turbo from over boosting and becoming a problem.

For the plug wire popping, do you mean popped out of the spark plug hole? That would take quite a bit of pressure which makes me think he not only has a bad gasket right there, but tons of crankcase pressure.

[Rajin]

Yeah Wes, he said it jumped, I ran the wastegate source (which is marked on these cheapo mbcs) direct to the wastgate and the other to the J pipe, I believe that was correct?

Yes, he said the plugwire jumped out of the hole. Blew my mind, wonder whats causing all that crankcase pressure. Any ideas?

Which gasket, headgasket or valvecover?

[WES_393]

I would just run a line straight from the J-Pipe to the wastegate. Eliminate the cheapo MBC all together. I'm thinking a bad valve cover gasket letting pressure into the spark plug hole. But it would be a good idea to check the PCV valve and valve cover vent (near rad cap) to make sure they are functioning/flowing.

[syoung]

Ok thank you Wes. The car is mine that is ghaving this issue. I'll just let you hear what i am having trouble with out of it. I bought the car and my friend said wait till i get a bettre controller on it for the boost so it don't mess anything up. I wasn't paying attention a few times and the boost gauge on it is only positive (switch to vacum line reading gauge also very soon) but it reads 12psi at times but if i ever get into it all the way it'll just climb up to 20-25. To me that is a boost leak and i got a good boost controller on the way now. Should be here this week.

As for the wire when looking at the motor it's the 3rd from left. I was at a red light car was completely fine. I was gonna get it rolling some and give it a bit of gas to get it really moving and as i gave it that bit of gas it just bogged down and didnt really go. It started missing and i pulled that piece off and that wire was just loose in the hole. I pushed it back down and checked the others all were fine on it and it still is missing just like then.

I have a coilpack and boost controller on the way in and i think i may as well change out the wires just to be sure it can't be in that at all. I just bought NGK bpr7es plugs because my friend said to and it helped that missing a little but I personally think that the wire tip is fried or even the coilpack. So im replacing it because the coilpack is stock looking and the car has 237k on the body.

When I get the wires, coilpack, and boost controller replaced i'll let you know more about what it is doing, but this is what we have ran into so far.

Now just an example of me driving. At about 50+ mph in 5th it doesn't want to really sound like it is mising but it is a little slight jerking just enough to notice it. As well the more gas i give it at to low mph/rpm in a given gear it wants to jerk and sound like it is missing more. I can hear it in reving the motor that it isn't right like there is a stutter in it. I'll be replacing the valve cover gasket and front and rear seals as well because i want to have this car very dependable, i know it has the balls as is compared to any other stock car i've owned and that is fine by me. I wanted something no one else has in town and now it is to maintain it and get it looking spiffy and what not

[Rajin]

It needs a valvecover gasket badly, lol it leaks oil like a stuck pig from right around there.

[syoung]

I will tomorrow. i'm off and i will be getting froint and rear main seals ABND gasket and replacing gasket as you said the seals will take a day to do. And again thank you and thank you Wes for the input. I hope to have it running smooth as a babies butt SOON! I want to have it not so crappy running, but i have had worse xD

[Rajin]

Also, the cars not got a leak in the traditional sense, its more a MBC failure allowing overboosting, or creep situations.

[islideawd]

is it possible your turbo is on its way out? or boost leak (vaccum line or boost controller) is causing the creep.

[Rajin]

The turbo seems fine, if not a tad loud for a 14B, but the MBC, god...it's trash. Straight up trash.