Dreamcar86
Active Member
- Joined
- Apr 13, 2006
GNVAIR said:Vacuum works fine. I have it on mine. My dad has it on his. Most of my friends have it. It plain works well and has been super reliable.
If you are having problems then here are a few suggestions (some are redundant):
check proper function of the booster (make sure there is no loud hissing when the pedal is pressed while engine is running. If you hear a loud continuous hiss while holding the pedal, then you have a hole in the diaphram and the booster should be replaced as this will be the spot where you will loose vacuum)
check proper function of the check valve
check vacuum source
make sure you have more than 10 inches of vacuum available (cams with a lot of duration and/or over lap will kill the vacuum)
make sure you dont have a misfire or a cylinder down on compression or a huge vacuum leak some where else (such as the climate control, cruise control or any of the other vacuum sources)
It should also be noted that there are 2 different boosters fitted to G bodies.
One is a single diaphram (large diameter, shallow housing depth)
The other is a dual diaphragm (small diameter, thick housing)
I always use the dual diaphram. The TTA's had a dual diaphram as well that was mechanically identical to the G body unit.
Anytime someone has a problem with the pedal loosing assist I strongly question many of the above items since it should work flawlessly. The TTA came stock with it (as is common knowledge) and utilized all of the same critical parts that a Buick would have (cam, intake, etc).
Many guys dont like it when the tune/running condition of their engine is questioned, but those things play a big part in your vacuum readings. Parts integrity is also crucial. Not that G body boosters go bad that often as I have never lost one personally, but it is mechanical and is possible. The one on my car is used from a salvage yard and has been on there for almost 5 years now.
I noticed that you said to use a check valve. If your vacuum source is the vacuum block on top of the plenum is the check valve necessary? If so, is there any special one to purchase? I have never ran one. What could happen if you do not run one?
Thanks in advance.