No boost in blower

Drummer

Registered User
This started on my way home today. My SC has been fine except for and intake manifold leak that is coating the ground under the car at work. The boost has been fine but on my way home today I had a semi "Road rage" incident. I hammered it down in 3rd and nothing. I looked at the boost gauge and it was sitting on 0, 12 o'clock but wouldn't go any higher. It went down O.K. but not over zero. Started down a semi non congested country road and tried it again with my driver side window down to see if I could hear anything and low and behold I heard a hissing noise like it was sucking air. Ummmm ~~~?
 
My SC has been fine except for and intake manifold leak that is coating the ground under the car at work............................................... Started down a semi non congested country road and tried it again with my driver side window down to see if I could hear anything and low and behold I heard a hissing noise like it was sucking air. Ummmm ~~~?

Sounds like a possible boost leak at the intake somewhere.
 
Seems like all my "issues" revolve around the intake manifold. I tried to take the supercharger off once but with no success. I just know that pulling the intake off is a BIG job. Am I right?
 
not really

just need to get that ratchet out and start turning...just a little time consuming but not difficult at all.
 
I think the most intimidating thing about this is the fuel rail. Almost sure that needs to come off.
 
The hardest part of the job by far is getting the belts off and back on the supercharger. the fuel rail has to come off but that only involves four little tork's screws and a stud on the back on the drivers side head, you don't have to disconnect the fuel lines from the rail unless you want to just to take the intake off...............Dan
 
I don't know ... 0 boost? That would be a massive leak. How could the car still run? I would be more inclined to think that the bypass is broken, the blower drive shaft broke or the belt snapped.

That is what I would do ... have an assistant run the car. Stand off to the side of the engine bay (out of harm's way). Have them brake stand the car just enough to get the vacuum to drop near 0. Does the blower bypass valve close? If not, that's probably where the problem lies.

If that is inconclusive, take the blower belt off (if it is still there), and see what happens when you try to turn the blower pulley. If it doesn't spin, the SC is seized. If it does spin, then the blower may be ok.

Next, take the blower top and upper IC tube off (as a unit). Inspect the rotors for any obvious signs of damage. Hold the rotors in place with one hand and try to spin the pulley with the other. The two should not be able to spin independently of each other. If they do, the drive shaft or coupler is broken. (Some of the couplers do allow a few degrees of "bounce" before the rotors will move - don't worry about that. They are spring-loaded. But the pulley should not spin freely more than, say, 10d before the rotors move.)

This work won't be wasted in any case because you have to do this to get to the intake manifold anyway.
 
I don't know ... 0 boost? That would be a massive leak. How could the car still run? I would be more inclined to think that the bypass is broken, the blower drive shaft broke or the belt snapped.

That is what I would do ... have an assistant run the car. Stand off to the side of the engine bay (out of harm's way). Have them brake stand the car just enough to get the vacuum to drop near 0. Does the blower bypass valve close? If not, that's probably where the problem lies.

If that is inconclusive, take the blower belt off (if it is still there), and see what happens when you try to turn the blower pulley. If it doesn't spin, the SC is seized. If it does spin, then the blower may be ok.

Next, take the blower top and upper IC tube off (as a unit). Inspect the rotors for any obvious signs of damage. Hold the rotors in place with one hand and try to spin the pulley with the other. The two should not be able to spin independently of each other. If they do, the drive shaft or coupler is broken. (Some of the couplers do allow a few degrees of "bounce" before the rotors will move - don't worry about that. They are spring-loaded. But the pulley should not spin freely more than, say, 10d before the rotors move.)

This work won't be wasted in any case because you have to do this to get to the intake manifold anyway.

+1

There is no leak that could cause the motor to receive no boost. Has to be a bypass or supercharger problem.
 
+1

There is no leak that could cause the motor to receive no boost. Has to be a bypass or supercharger problem.

+2
Total agreement on the 0 boost problem. These cars need a bit more maintenance than most cars but they are not as hard to work on as some would have us think. While rocket science training might help in the tuning of these cars they are help together with nuts and bolts much like all other cars---no need for fear..................Dan
 
You guys have my head spinning. Where is the blower bypass valve located? Any pix for this?
 
sounds like the harmonic balancer broke and twisted mine did that runs on level but any hill forget it and no boost, i have an 89 5 speed and 90 automatic , on my 89 the 2nd harmonic balancer broke clear off and had to be towed home thats when i bought the good steel one that wighs 7 pounds more than stock yes it does feel slower but o well at least it wont break
 
Last edited:
I have a question...Does the power seem way down..like in no power at all?..If not it may just be an issue with the gague or line to it...0 boost is like 0 power
 
Back
Top