exhaust pops under boost

[1FASTRICE]

my car drives fine until I hit boost, then it pops like crazy and cant go any faster... any ideas?

it will rev up fine when not in gear

 

[GVR4592]

How much boost? When did it start doing this? Have you recently done any modifications? Do you have a datalogger? Did you do a boost leak test? How are your plugs? What are they gapped to? Have you checked base timing and fuel pressure?

 

[siceclipse]

im going with spark plugs or wires
check and replace both if necessary

 

[1FASTRICE]

i have no clue how much boost im running, i have a manual boost controller and i cant get into the boost to tell hom much im running. i know the plugs should be replaced, didnt think they could affect like this and the timing is right on. the plug wires are brand new

 

[GVR4592]

Well that answers one of my questions.

 

[1FASTRICE]

which one would that be?

 

[GVR4592]

I was being a smart ass. There are a lot of things that can cause the problems you are experiencing. You didn't provide enough information to help you diagnose the problem. That's why I asked those questions. You only answered one of them. We need more information.

 

[1stGenRocks]

do you have a real boost guage? does it pop as soon as you go above 0 or only after 5 psi or what?

do you hear a loud whistling kind of sound?

 

[Xplicit93AWD]

Well to me with the info that you provided it sounds like it might be a boost leak have you done a boost leak test if not I would do one and I pretty much gaurantee it should fix your problem so try that and then post back. Also like the above post says do you hear a whinning sound while driving if so then it just reasure me that you have a big boost leak somewhere that needs to be taken care of.

 

[1FASTRICE]

I was being a smart ass. There are a lot of things that can cause the problems you are experiencing. You didn't provide enough information to help you diagnose the problem. That's why I asked those questions. You only answered one of them. We need more information.[/Q
actually i answered 3 but it doesnt matter... i think the leak may be comming from the rubber hose i have connecting the intake to the bov

 

[1FASTRICE]

do you have a real boost guage? does it pop as soon as you go above 0 or only after 5 psi or what?

do you hear a loud whistling kind of sound?

what do you mean real boost gauge? i have the autometer phantom boost gauge. and it starts popping around 3 psi

 

[staticbrainwash]

If you have an Autometer boost gauge how can you not know what boost you are running?? That makes no sense.

Do a boost leak test, pull plugs and inspect.

I'm going with a leak somewhere.

 

[mavisky]

With it only showing 3psi, you've got a major leak somewhere.

If you fix that and it still does it, then it may be plugs.

 

[1FASTRICE]

ok for the people not paying attention to what im typing....

there is no way for me to tell how much boost im running if when it goes into boost and pops at 3 psi the throttle will not make my car go any faster for the boost to be produced and read more than 3 psi.

as for the guys telling me about the leak, im with you guys on that 1, im thinking the source is where the rubber tube connects to my bov and intake. there is no clamp on the end where it connects to the intake connecting to the turbo... thanks guys

 

[staticbrainwash]

I am reading you correctly, and if you're only ever reading 3psi, you have a mojor problem. And it's not as simple as a leak at the BOV return to the intake. Because, a working BOV won't let boost past it until vac incurrs. Therefore you can't be experiencing that kind of leak at the return line. You HAVE another leak and NEED to leak test.

If there is a leak at the BOV return at the intake the only thing that could happen is you would be pulling in un metered air, or leaking unmetered air before it is compressed at the turbo. Which would make you run real weird, but not cause an issue under boost like you are experiencing.

YOU NEED TO LEAK TEST! Then we can decide how to rectify the issue.

Also check to make sure the boost/vac source for you gauge isn't kinked and is in the right location to read both boost and vac. And, make sure you have no pre-turbo exhaust leaks, that could be an issue also, as it is with me right now. (Just don't have the time to have the car down to start pulling the 4out of 9 bolts that are broken, though i know i should make time. I just don't have acess to some of the things i need to pull busted bolts from the head.)

We're all trying to help here, so don't get snippy. You just need to do what we are telling you so we can all help you further. Because until you leak test and replace plugs, this is all just speculation.

Thank you, goodnight

 

[T9S1i]

i had a popping in my car before. That was the sign for me to to upgrade to colder plugs (bpr7es - ngk) and gap them at .28 ( or is it .028?) with a FEELER GAUGE, not one of those kragen circle ring things with the different sizes on it. I replaced the plugs and gapped them correctly and it helped my problem.
I guess the popping was spark plug blow out so the gap was the main problem. This was a year or so ago so i cant remember exactly.

Hope this helps!

 

[Talesin]

If it's only happening under boost, it's extremely unlikely to be a spark problem.

Make a boost leak tester, and use it. Speculation will get you nowhere.
http://www.vfaq.com/mods/ICtester.html

Hook that to your turbo, pressurize your intercooler piping to about 20psi, and listen. The hiss will lead you to your worst leak. Fix it, put more in, fix the next leak. And so on until it can hold 20psi for about 30 seconds or so.
With a leak that bad, I'm going to guess either a coupler completely off, or a hole in your intercooler.

 

[staticbrainwash]

^^ And how! I didn't even think about an intercooler issue. Good call.

 

[gridlyne]

It sounds like a boost leak to me. Same thing happened when my UIC popped off.

 

[T9S1i]

Hmmm interesting. I couldnt really tell what he was talking about from his discription. A pop from the exhaust isnt much to work with. I initially thought it was a pop pop blub blub blub pop pop.... thats what reminded me of when i had spark blow out.

If you are just getting 3psi and then a pop and no more, i would also have to agree that its a nice sized boost leak.

 

[staticbrainwash]

Why he hasn't leak lested in the past, or at all yet is beyond me.

Especially seeing as how thats THE FIRST THING anyone with a dsm should do before they push more boost. DER

 

[1FASTRICE]

Why he hasn't leak lested in the past, or at all yet is beyond me.

Especially seeing as how thats THE FIRST THING anyone with a dsm should do before they push more boost. DER

Well considering the car ran fine when i took it off the road for the winter, i sawpped in a 1g motor in that time and the day i posted that thread is the first day i brought it back out, i just thought it had to work out some kinks from sitting for 6 months.

and yes it was a boost leak in the IC piping. The elbow that connects to the lower part of the IC was a little twisted causing the clamp not to seal/tighten correctly.

Thanks for the help

 

[Xplicit93AWD]

No problem happy to hear everything worked out fine. If anythign else hit me up on aim. peace

 

[94 TSI AWD]

Mine is doin the same thing... but.. i hit 10psi then "pop" but i think mine is spark being blown out...i have ngk6's in it right now im thinkin bout goin down 1 or 2 steps colder...and i have no boost leaks...front o2 is new.. rear o2 isnt new...and im not runnin my boost controller till the motor is broke in...

 

[staticbrainwash]

Stock turbo? I highly doubt you will need colder plugs for stock psi. Unless it's a big big turbo on 10 psi. Stick with 6es's and just get new ones.

Check for leaks, and pre turbo exhaust leaks. It's always the easiest place to start.