new engine,new member,low boost

croglesby

Registered User
hello kind peeps of my fellow thunderchicken lovers club. I just had a new engine put in my 5speed 89 sc. Im getting plenty of vac( around 20+ ) but no boost. with wot The gague goes to 0. I was checking the bypass valve and it is not moving. In fact it is hard to move. IF I move it by hand and rev it I get a + boost reading. does this mean I need to replace the bypass valve? I tried to search in the threads but could not find this prob. Much thanks ahead of time for your input.:) It does close slowly!!! when I shut it off
 
Last edited:
try wiring it open and see if that changes it, but yes i d have to sy thats the issue, but like i said use some wire and wire it open and see if she BOOOOOOSTS up:D

-Tony-
 
It works off of vac so if you disconnect it and rev the motor you should get full boost but you will not see more than 5. You get max boost in 2nd @ WOT.
Depending on year of car, 89-93 get 10-13. 94-95 see about 13-15. If you get full boost the post in the wanted section for a bypass valve and another menber can help you out. Welcome to the club
 
i will have a bypass for sale soon as my car was just totaled! Watch the for sale threads as the car will be parted out most likely!
 
I was talking about the normal amount of boost. My 94 would max out at 17 with no mods but exhaust blockage had a role in it. In fact 89 has a computer controlled boost actuator. You can get the boost gauge to bounce all the way if you flip the throttle from what I remember. Been so long since I have started mine, I will need to go out today and fire it up.
 
Just to point out, tying open the valve well net you no boost :cool:. The valve has to be closed to get boost.

Get yourself another valve. It should not be hard at all to open close that valve by hand even when its running.
 
Don't run the car with the valve closed either. When the valve went on my car, it was stuck shut, and at idle my ACT's climed to over 200 degrees in the matter of minutes from the blower cavitating.

Replace the valve.
 
thanks guys

yes its getting boost now thanks guys. well I called around and no one carries the part anymore so this is my best bet to get anouther. right now im in Evansville IN. some one price me one please
 
Last edited:
Back
Top