PDA

View Full Version : boost problems... boostcut :(



discontained
08-04-2007, 03:44 PM
Hey everyone, i have a boost problem. I cant seem to get this right...

Here is the problem. I had a bad vacuum line.. had a boost leak and then i finally narrowed it down to this hose.

http://a145.ac-images.myspacecdn.com/images01/82/l_de6ebeef0e1463643c406169d0c089a0.jpg

http://a85.ac-images.myspacecdn.com/images01/92/l_c5c1266adf4ef08f55ec5f6f2eb07fd4.jpg

So.. i replaced it, now i can boost upwards of 13psi, but now it goes to 15 than boost cuts... ???? [headbang]

any idea's? i cant even hold steady as soon as it gets to say 15 it goes down to 5 psi....

thanks!

Audi91a4
08-04-2007, 06:07 PM
Im having a similar problem as well! Im only hittin 13 psi. Sometimes it even goes to 15 then right down to 5. What hose is that and where is it located?

1.8tizzle
08-15-2007, 01:40 PM
yeah what did that hose come from?

AustinQuattro
08-27-2007, 09:47 AM
I just replaced mine as well. There is a pump that connects to that hose on one side and above it is a check valve. When I went to replace the pump, I saw that the hose was the problem. Maybe your "pump" is bad. It is a black plastic piece that connects there. I also heard a pretty loud "whoosh" when the boost was on coming from under the drivers side of the dash.

Just a thought. I changed the check valve while I was at it...apparently, all the rubber pieces will get brittle and crack or break after so many years. I also replaced 4 vacuum lines (most of the other ones had already been replaced) while I was down there.

salz2135
08-27-2007, 11:20 AM
what year is your car? where is that hose from? if you're a DBW car you might be experiencing throttle cut because your actual boost is exceeding your requested boost at unacceptable levels.

did you scan for codes?

Jereme
08-27-2007, 01:55 PM
yeah are you chipped?

I bet if your hitting 13-15psi unchipped then your getting throttle cut, or your cars going into Limp mode to protect it from overboosting...

Naudilos
08-30-2007, 10:42 PM
The picture above is an L hose that connectes into the intake manifold. I just replaced mine along with the braided vacum lines around the intake manifold. BUT just like discontained I am still having boost problems. I had the car checked for boost leaks and nothing was found.

I am only boosting around 10 psi with a giac chip right now, and after driving around for a while it will not go past 5 psi. When it is hitting 10 psi the boost is comming on rather hesitant at first then shots all the way up to 10 psi.

Could it be that the maf is on its way out? What is a safe way of cleaning it?

mike-2ptzero
08-31-2007, 05:18 AM
The picture above is an L hose that connectes into the intake manifold. I just replaced mine along with the braided vacum lines around the intake manifold. BUT just like discontained I am still having boost problems. I had the car checked for boost leaks and nothing was found.

I am only boosting around 10 psi with a giac chip right now, and after driving around for a while it will not go past 5 psi. When it is hitting 10 psi the boost is comming on rather hesitant at first then shots all the way up to 10 psi.

Could it be that the maf is on its way out? What is a safe way of cleaning it?


Could be the maf, but it could also be that your bpv is not closing when it should since it is controlled by another valve under the intake manifold. Have you tried by passing that valve and moving the vacuum line to the bpv directly to the front of the intake manifold?

Naudilos
08-31-2007, 09:13 AM
No I haven't tried that yet. I'll take a look at it today. So, I should try running the car with out the bpv and if it works better then I should replace it? Would a 710n be a good enough replacement?

mike-2ptzero
08-31-2007, 03:10 PM
No I haven't tried that yet. I'll take a look at it today. So, I should try running the car with out the bpv and if it works better then I should replace it? Would a 710n be a good enough replacement?

Try bypassing the small valve that controls the bpv first.

Naudilos
09-11-2007, 03:51 PM
Well I replaced the old bpv with a 710n and I cleaned out the maf. The car is running a whole lot better and smoother, but it is still not reaching 18 psi. The higest it goes is about 16psi and holds at 11 psi.

Any other suggestions that I could try to get the car running the way it should?
Maybe a stock N75 valve or just get a new maf...?

salz2135
09-11-2007, 04:15 PM
does the throttle still cut, or are you simply not hitting peak boost?

have you done a pressure test?

Naudilos
09-11-2007, 04:33 PM
The throttle doesn't cut out anymore like it was doing before. Now I am just not hitting peak boost.

I took it in to Rennart and had them do a boost leak test, and they said that there were no leaks. I have already changed out 3 vacum hoses and the L-hose above going into the intake manifold.

salz2135
09-11-2007, 04:52 PM
if you think its MAF related you need to log the voltage and see what numbers you're getting. if they are below spec then your MAF is likely on its way out. you don't want to be buying a new MAF if that's not the problem.

Naudilos
09-11-2007, 10:42 PM
Yeah, I think that's what i'm going to try next and see where I can go from there. Just need to find someone with a vag-com.