Won't build boost

[scgnx]

My buddies 87 GN with a TA-49 turbo, stock downpipe/cat/wastegate won't build more than 5 lbs of boost. Car runs fine (just slow), turbo sounds okay (no smoke,etc). What should we look at ?

 

[1970gsx]

Check the wastegate rod, it may be to loose. You should have to tug on it a bit (like an 1/8 of an inch) to pull it on the arm.

 

[scgnx]

Yep..did that. Even wired the gate closed with a coat hanger to
see if the actuator was messed up. Still only 5 lbs..Is it possible that convertor is plugged up and putting backpressure on the turbo to cause this ???

 

[Scott231]

YEP, big possibility. I bet the spark plugs look like Hershey bars

You should be able to hit 10psi with the wastegate actuator rod disconnected....

 

[scgnx]

Convertor is original, will pull the plugs tonight..Thanks a bunch!

 

[XLR8]

Plugged Cat?

 

[Scott231]

Originally posted by scgnx
Convertor is original, will pull the plugs tonight..Thanks a bunch!

Original, like 15+ years old! Ding, ding, ding...

 

[Turbo__Tim]

It's the cat. Hammer and pipe time!