enginge "chugs" under heavy acceleration and boost

[dyep8ball03]

69 tsi awd. only mod is a front mount.

ive recently been having a problem with a surging/chugging when im accelerating and my boost is at or above 8psi. so i ran a boost leak test and found my leaks, fixed them. ran a comp test and have almost perfect comp across the board. performed an injector clean service. new plugs and wires, and i tested the coils and i have a strong spark. also reset timing so that is good. i drove it home and found it was still doing this. also when i was almost home oil pressure gauge dropped out. when i got home i lifted the hood to check everything out and saw my turbine housing was glowing, oil level is at full.

but, if i lightly accelerate to WOT and full boost it performs fine. any suggestions??

 

[dyep8ball03]

it also sets a cylinder 4 misfire code

 

[zhjiln]

hmmm..it still sounds like a spark or fuel problem

 

[dyep8ball03]

well i got home from work today and pulled the exhaust mani off and found that starting from passenger side to drivers side the valves show more "heat" by the color of them. like #1 looks okay, 2 shows a little warmer #3 shows a little warmer but 4 shows way too hot. ive put a used injector on there ### i had an injector issue and also a new regulator. could i possibly have the wrong regulator?

 

[joeyzaza]

You could pull off your lower intercooler pipe and check if there is oil in there, also check the turbo for shaft play. Those are signs of a bad turbo.

Usually chugging while in boost is spark plugs not gapped right, or wrong ones. Use only NGKBPR6ES. Old plug wires. I recommend NGK aswell. Or the most common boost leak. I thought I had all mine fixed and it turned out it was the throttle body shaft seals, I installed new ones and WOW night and day difference.

Make sure when doing boost leak test, you pressure the system to 20PSI, it should hold for a bit, and then SLOWLY start falling off.

If you have a logger, you could check what the fuel trims are, if it shows rich or lean, it maybe the FPR.

Good luck, just owning DSMs is a great way to learn how to fix cars, they are always broke!

 

[dyep8ball03]

there is a small amount of oil in the lower pipe, nothing major. and there is virtually no shaft play on the turbo whatsoever.

and as for plugs im running bpr7es gapped at .028 and newish wires. maybe 2-3 months old?

 

[niddydsm]

if you think its a FPR take the vacum line off and see if there is fuel in it if it has fuel in it theres your problem. and defintley check boost leak again.

 

[dyep8ball03]

fpr is maybe a few months old, and the diaphram is fine. no fuel on the vac side.

 

[joeyzaza]

Oh I forgot to add, if you are having a mis fire, pull your plugs and check for differences. I had a miss fire once " I put the plug in without taking off the compression tester end" the plug was all black and nasty.

I have read to use the NGK 6s unless your car is running high boost, I ran the 7s once but it made no difference.

 

[dyep8ball03]

the miss is only on cylinder 4 under high boost if i send the pedal to the floor. otherwise it doesnt miss

 

[joeyzaza]

Have you changed anything recently, or did this just start to happen out of no where.

 

[dyep8ball03]

i did the injector service a few days before it started to occur. but then i found some obvious boost leaks and fixed them which fixed the problem for a few days. but then it would start up again

 

[joeyzaza]

If you actually took out the injectors, it could be an injector seal.

I would try to switch the plugs around to different cylinders, reset the ECU, and see if you get the same mis fire. You may even be able to switch around the plug wires, making sure to switch the ends on the coil too, reset ECU and test again.

Seems like a spark issue, but a sneak boost leak will do the same!!!

 

[dyep8ball03]

i may have one of my boost leaks back then. i have a 1g crushed bov on an adapter plate (came with the car) and the plate has four holes drilled into it , two that the bolts fit thru and two more between the bolt holes and the bov port. on the 1g ther is a branch that goes out to the side that lines up w one of these holes nd during the boost leak test it was pissing out that hole. should something be plugged in there? or do i need a new adapter plate

 

[joeyzaza]

Sounds like your upper intercooler has a flange that supports 2 types of BOVs, not uncommon, mine is like that too. There is a small hole under the BOV, thats a quick release. That should just sit flush with the flange. If you are getting air comming out one of the flange holes then thats a problem. You maybe able to fill those in and smooth them out with some JB weld. Mine works fine and does not leak.

If you are having a leak at the BOV, that may just be the first leak. When you fix one, you'll find more.

What boost are you testing it at, and how long does it hold it?

 

[dyep8ball03]

im testing at 10-12 psi constant pressure

 

[dyep8ball03]

i found that leak and then a leak at i think the iac motor?? o-ring. if u take the intake pipe off at the tb its the sensor right below it. i sealed both of those and heard no more air escaping the system and it took a long time to bleed out thru my pressure regulator after i disconnected the air

 

[joeyzaza]

You should test it at atleast 15PSI, thats what your turbo puts out. Use a spray bottle with soapy water to check for more leaks.

What does your cylinder 4 plug look like compared to the others.

 

[dyep8ball03]

normal, i pulled em all and they all look like new. and as for the soapy water i sprayed it down and nothing else was bubbling out but ill test at 15 tomorrow then.

 

[joeyzaza]

Good luck dude, I thought I had all my boost leaks fixed and my shaft seals were bad. I never saw bubbles, but when testing I opened the throttle, and the noise changed. Tell tale sign. I fixed that and it was night and day difference how the car boosted, and ran!

If its not a boost leak, I would get new plugs and wires.

 

[dyep8ball03]

thanx man. ill post what i find. and the shaft seals are on the ends of the butterfly right?

 

[joeyzaza]

The shaft seals are inside of the throttle body, it must be removed, and semi taken apart. There are some really good write ups how to do it.

It may not be your issue, but a boost leak from there is very sneaky. That was what was wrong with my car awhile back.

 

[dyep8ball03]

found the boost leaks comin from the bov and the injector seals. also found wires on #1 and 2 had rub marks on them. replaced wires and fixed up the boost leaks and were good to go thanks guys

 

[joeyzaza]

Good stuff, I hope my car is fixed too. Its just too cold and snowy here to test it.