Low boost

SCTIM

Registered User
Hey guys, its been 2 years, and i finally got another sc, only, i seem to be only pulling about 7-8lbs of boost. I noticed at idle, i am hitting about 25-28lbs on the vac side, which seems a little high. If i remember correctly, i should be sitting around 18-20lbs. If anyone has an suggestion, please let me know, or please verify where i should be sitting at idle...

Also i don't know if this would affect anything, but sometime my tach wants to work, sometimes it don't..
 
>...seem to be only pulling about 7-8lbs of boost. I noticed at idle, i am hitting about 25-28lbs on the vac side, which seems a little high.

Sounds like your gauge is reading 5 points low on boost/5 high on vacuum - might want to try another gauge.

>sometime my tach wants to work, sometimes it don't.

Tach going out... Does the car run rough or is it hard to start?

Has the dash cluster been out of the car recently?
 
Hey guys, its been 2 years, and i finally got another sc, only, i seem to be only pulling about 7-8lbs of boost. I noticed at idle, i am hitting about 25-28lbs on the vac side, which seems a little high. If i remember correctly, i should be sitting around 18-20lbs. If anyone has an suggestion, please let me know, or please verify where i should be sitting at idle...

Also i don't know if this would affect anything, but sometime my tach wants to work, sometimes it don't..

The tach might very well be your cam position sensor. The boost thing could have to do with your mods. The more you open up the exhaust the less boost you have. Do you have a early model blower? there is a point you get to where you can OD the crap out of one and still not make much boost.
 
boost problem

Ok, i was thinking the same thing about the guage reading off, but it doesn't feel like it pulls the way is should, i am gonna try and reseal the ic tubes, and blower top. It looks like when they installed the motor and put everything back together they didn't use good sealant. looks like the indian head crap in the brown bottle, so i am gonna reseal with hi-temp copper rtv.

As for the guages, the car does have a miss at idle. The cluster has been out at some point. Previous owne installed white face guages. So it could be a loose connection or maybe the vac line is pinching on something..

I haven't had the pleasure of getting under the car all the way, but it looks like its stock exhaust with delete resonator, and just some Flowmaster mufflers welded on, sounds good, but might be hurting it..
 
>Previous owner installed white face gauges.

Does the vac/boost gauge needle sit at '0' when the car isn't running?

>Get a new DIS and Crank position sensor.

I wouldn't spend that kind of money just yet...
 
i checked the guage, and its reads about 7 on the vac side while the car is off... Does this mean the guage is just off, or is it something else. Is there a way to calibrate the guages or something?
 
>checked the guage, and its reads about 7 on the vac side while the car is off... Does this mean the guage is just off, or is it something else. Is there a way to calibrate the guages or something?

That's what I thought - I'd guess when the white gauge faces were done, the needles were removed and then they were either put back on wrong, and/or damaged in the process.

With the issue you are having with the speedo as well, it sounds like that gauge is hurt. They are all fragile.

You can try removing the needle off of the vac/boost gauge and setting it at '0' when the car isn't running, or you can replace the gauge. Use a fork to gently coax/pry the needle off (it might just come away very easily...) and re-index it @ '0'...if it seems loose, you can maybe try gluing it on, but I'd start looking for another complete gauge cluster.
 
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