Black smoke and hesitation at WOT - no codes, need help

[aubiexx]

When at wide open throttle at times I am getting major hesitation. Sometimes feels like a loss of power and sometimes feels firm hesitation like a misfire. There is also significant black smoke when this occurs.

I hooked up my VAG com and there are no codes pulling from this. Anyone have ideas on what may be the issue?

Is there a module I could use in the VCDS software that will show misfires, that don't necessarily trigger a CEL?

[Low and Behold]

More info please. Mods, mileage, oil consumption?, etc.

Changed your plugs recently? coil packs? You could check your fuel pressure in VCDS. Maybe you're running lean, but tough to tell without more info

[KJack]

In my experience, lots of smoke and hesitation at WOT was the result of a cracked valve cover. My smoke was more gray though. Is there a lot of oil collected in your intercooler pipe?

[aubiexx]

Thanks - I have not checked the pipe yet, but can do so.

I'd prefer to be able to look at any misfires via vagcom log first. Please let me know if anyone can help with that. I can only find how to do that while it's live, and not look at a historical log. Frustrating because the problem doesn't happen all the time. I think mostly when it's really hot outside and I'm up to temp.

FYI - I'm chipped and that's all. Oil consumption is about 1 quart every 2500 miles. Changed plugs about 10K ago. 125K miles. All but one coil pack is original.

[RickB_7]

Yeah your issues sound like what I went through with my valve cover.

[hemantpd1]

may be cracked VC or leaky VC gasket, but do a compression test first.

[aubiexx]

What's the best/easiest way to diagnose a cracked valve cover?

I have changed diverter valve and pcv and valve cover gaskets due to oil forming on top of the valve cover. Is it possible that I have oil in my intercooler from previous problems that are now fixed and I just need to drain the intercooler?

[KJack]

What's the best/easiest way to diagnose a cracked valve cover?

I have changed diverter valve and pcv and valve cover gaskets due to oil forming on top of the valve cover. Is it possible that I have oil in my intercooler from previous problems that are now fixed and I just need to drain the intercooler?

Remove the valve cover and do a visual check on the underside. Is your valve cover silver or black? The crack issue seemed more prevalent with the silver ones. Check out the thread below for further VC troubleshooting. Scroll down to the photo and description:

http://www.audizine.com/forum/showth...VE-valve-cover

It is possible that a collection of leftover oil in the intercooler is causing the issue, so that would be an easy first step to check.

[aubiexx]

Thanks. My valve cover is black. From the outside it looks very clean.

I'll plan to check for oil this weekend in the IC and follow up.

[Charles.waite]

BLACK smoke would be improper combustion. BLUE smoke COULD be valve cover. OP said black smoke.

OP, My guess is, with e combo of black smoke and hesitation, you're getting bad misfires. I would check your plugs and see what they look like. Ignore the bozos who are saying its your valve cover, they're confused.

If I were in your shoes and I didn't know the age of my plugs or coil packs, I would just buy all new both. Good OEM Bosch (FR6KPP332S) or NGK plugs (BKR7EIX) run about $8 each and good OEM coil packs (p/n: 07K905715F) run about $20. Keep in mind that the proper heat range for the 2.0t is NGK-7 or Bosch-6. Don't let anyone tell you otherwise. Older 1.8t engines used to have a NGK-6 heat range stock and its a VERY common misconception in this forum that the 2.0t shares this. the 2.0t is one range colder stock.

Hope some of this info helps

Edit: Just saw you said you changed plugs 10k miles ago. What plugs did you use? If you used copper based plugs (bkr7e or bkr6e) then those plugs have reached the end of their service life and should be replaced anyway.

[yeoj112689]

I would change your plugs as stated and gap them properly. Also if you have vagcom record your fuel pressure because as Charles stated it sounds like you're not getting the proper combustion which would explain the extra fuel getting into your exhaust and igniting as well as the hesitation if you are misfiring. I had the same issue when I got my tune, change the plugs to a colder plug and gapped them properly and never had an issue again.

[aubiexx]

I got an opportunity to check the intercooler hoses. The driver side had about 6 ounces of oil and the passenger side had about three. Taking it out for a drive and I'm still getting a little bit of hesitation at WOT.

[Low and Behold]

Ignore the bozos who are saying its your valve cover, they're confused.

Lol. Just read this.

I wouldn't call them bozos per say, or confused. Probably just speaking from personal experience which I agree with and have experienced myself.

I got an opportunity to check the intercooler hoses. The driver side had about 6 ounces of oil and the passenger side had about three. Taking it out for a drive and I'm still getting a little bit of hesitation at WOT.

We all agree the plugs should be checked at the very least, but inspecting the VC is so easy it might as well be looked at. Speaking of plugs, OE ones should be perfectly fine for a stg. 1 tune. What did you replace yours with?

[aubiexx]

Swapped plugs for Bosch OEM. Image below.

The 3 that have some gunk on them are the ones in the original coil packs. One had so much build up I had to break it away to get my socket around the plug.

I have not been able to get out yet, but thought to send this update.

http://s16.postimg.org/dgv0qpek5/unnamed.jpg

[RickB_7]

Yeah sorry not a bozo or confused. My car was definitely making black smoke when I had oil going through the valve cover into the pcv system. Had all the same symptoms OP has. Under WOT or going up hill my car would start to misfire/hesitate and make lovely clouds of black smoke for the people behind me and also found plenty of oil in the intercooler hoses. I could post the picture of the bottom side of my valve cover and the very obvious split in the glued together plastic, but OP you should change everything plugs, pcv, fuel system , and your turbo is probably bad too you should get a new one...

Please just take take your valve cover off and inspect the bottom of it. Also my spark plugs had oil build up where they met the coil packs especially the two spark plugs at the back of the engine (could be 3rd and 4th cylinders). I find it interesting that one of your spark plugs looks very clean possibly the one toward the front of the engine? Where the valve cover doesn't have any ports to connect to the pcv system (where the crack on the bottom of my valve cover was). Ok done with my rant I'll go back to being a confused bozo...

[Charles.waite]

Good. You confused bozo.

[aubiexx]

Yes, my front most plug was the clean one. Will check the vale cover when I get time.

[yeoj112689]

Oil in the IC is a very good sign of a bad VC, I had the same problem. I plastic welded the VC inside to stop it from opening up again, made a huge difference. When it was sucking up oil I noticed it more on very strong vacuum (high rev no boost) if that makes sense.

The black smoke is extra fuel that could be caused by a misfire which could be caused by the oil fouling the plugs from the leaking IC. So basically everyone could be kind of right and there is no need for name calling ;)

[Charles.waite]

Oil in the IC is a very good sign of a bad VC, I had the same problem. I plastic welded the VC inside to stop it from opening up again, made a huge difference. When it was sucking up oil I noticed it more on very strong vacuum (high rev no boost) if that makes sense.

The black smoke is extra fuel that could be caused by a misfire which could be caused by the oil fouling the plugs from the leaking IC. So basically everyone could be kind of right and there is no need for name calling ;)

Is too! You bozo!

I was mostly poking fun, but the broken valve cover causing all the problems thing is the new golden bullet. It used to be "replace the N80". Yea in some cases that helped whatever random symptom the person had, but in other cases it did nothing. At least the N80 is cheap. A new VC isn't cheap at all, and I just hesitate suggesting someone play parts darts with$250 parts. I would know, I did exactly that and it didn't make a lick of difference for my oil consumption.

[yeoj112689]

Is too! You bozo!

I was mostly poking fun, but the broken valve cover causing all the problems thing is the new golden bullet. It used to be "replace the N80". Yea in some cases that helped whatever random symptom the person had, but in other cases it did nothing. At least the N80 is cheap. A new VC isn't cheap at all, and I just hesitate suggesting someone play parts darts with$250 parts. I would know, I did exactly that and it didn't make a lick of difference for my oil consumption.

I agree, I am not for throwing random money but it is a easy place to check, costs nothing to look :D

[softcheeksprod]

I've been having an issue like this for a long time couldn't figure it out for almost a year no cell either then just recently it got really bad found out it was a faulty knock sensor I had the all the symptoms WOT misfires then partial throttle missfire black cloud of smoke behind me hope this helps


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[Solarsuplex]

I HAD TONS OF BLACK SMOKE. I tracked it down to my n75 being shitty and thus causing my wastegate to be shitty and ended up with not enough air to fuel so i would get bogged down at WOT and black smoke.

So i did a rebuild from the pistons upward, head gasket and everything north of that. Turbo included.

Do any of you guys that had to replace your VC have catch cans?

[audinecroB7]

I HAD TONS OF BLACK SMOKE. I tracked it down to my n75 being shitty and thus causing my wastegate to be shitty and ended up with not enough air to fuel so i would get bogged down at WOT and black smoke.

So i did a rebuild from the pistons upward, head gasket and everything north of that. Turbo included.

Do any of you guys that had to replace your VC have catch cans?

Hey Guys if anyone is having this problem bluish white smoke like a lot during WOT lagging on acceleration and oil built up in the innercooler pipping it's THE VALVE COVER hairline crack air testing couldn't catch it! I changed the turbo, DV , coil packs, cam follower innercooler and still had the issue car runs fine no codes but during WOT super lagged misfire and a big ass plume of smoke finally changed the VC and runs perfect now a few shops couldn't even find what the issue was but check the VC it is a little pricey but if you have done everything else and still have the issue try this!!!! Cost from JHM labor and part $504.00 not bad for 8 months with this issue almost got rid of the car... hope this helps

2007 a4 b7
Stage 1 jhm tune
Straight pipe
AEM intake worthless btw

[Okedokey]

Its black smoke.

[StanShepel]

So i had the same thing happen, turned out to be the sparkplugs where the gaps for some reason or another changed. No codes, changed pcv etc. In the end, a small cheap test with new double platinum plugs. The bad ones turned out to be iridium plugs that are gapped improperly.

[aubiexx]

To close out this thread, I replaced the valve cover and have been driving for a month. None of the symptoms I had experienced have returned.

[Low and Behold]

Sounds like those bozos were right!

Glad to hear it's running well

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[Charles.waite]

Haha. Damn!

Glad it sorted your problems though!

[KJack]

Since creepy clowns are getting such a bad rap these days, it's nice to see the Bozos do something good for mankind! Glad to hear it fixed you issue!

[Theiceman]

To close out this thread, I replaced the valve cover and have been driving for a month. None of the symptoms I had experienced have returned.

just curious did you just swap it or did you remove it and inspect it and found visible damage ? ( cracking )