Whers' the boost?

[Amodeo]

I just completed replacing all my intake and exhaust valves on my '91 Eagle Talon TSI AWD (don't ask). The engine started and runs fine with one exception. At idle is shows a negative pressure. When reved, it goes exactly to atmospheric pressure but will not show positive pressure. When driving, it launches as usual but does not give the kick at about 2000 - 2500 RPM it used to when the turo "kicks in".

I think the turbocharger bypass valve may be stuck in the open position. Has anyone had this probelm? How can I test this? Would I get the boost to atmospheric pressure and no more if it were stuck open?

Any help would be appreciated.

Thanks

 

[ECLIPSE4x4]

try doing a boost leak check on it. There are procedures for this on www.vfaq.com

 

[LandoAWD]

Make sure the actuator rod is still connected to the flapper.

 

[greddyracer]

i ahve the same problem, and do you have the stock boost gauge. hopefully not.

 

[Amodeo]

Unfortunately, I do have the stock boost guage. I know its not particularly accurate but it does indicate positive or negative pressure.

The thing that bothers me is that the boost dies right at an indicated atmospheric pressure which makes me think the turbo (which I inspected when I had the exhaust apart and it was in good shape) is making boost but the system is not allowing possitive pressure. The only two things I can think is that the wastegate isn't working or the turbo bypass valve has failed open.

I was thinking of checking the air flow out of the turbo at the intercooler inlet. If there is pressure there, I can eliminate the wastegate and confirm that the turbo is working properly.

What do you think?

P.S. The wategate rod is connected and I can find no leaks in the system.

 

[ECLIPSE4x4]

Like I said... DO a boost leak check. And get a real boost gauge. We can not speculate on the problem if you do nothign like we tell you.

DO A BOOST LEAK CHECK.

 

[Amodeo]

O.K. I'll do the boost test this weekend. I'll report back what I find.

 

[Amodeo]

I preformed the boost leak test as instructed and could not locate any leaks in the intake track. I did find one small leak in a vacuum line that wasn't connected securely which I fixed. But no other leaks.