I have an 89 sc with no boost. I parked the car for about an hour went to drive it and no power at all. The gauge will read 20 in/hg vaccum and go to zero when I get on it, never into boost. My IC tubes are tight and leak free. What else could it be? It runs fine except the no boost part. Thanks Derek
What would cause my car not to boost?
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stocker 89
Registered User
Belt came off.
In my case. Tensioner broke and wrapped it around the the inside of the SC pully still turning and ripping it up .No boost. crazy luck . 16.00 Autozone.
In my case. Tensioner broke and wrapped it around the the inside of the SC pully still turning and ripping it up .No boost. crazy luck . 16.00 Autozone.
turbospeed
Registered User
if belts are ok then you have the same problem as my 90 sc had the BCS boost control solenoid , most sc dont have them just some early models. disconnet this vaccum hose and go for a drive if you get boost its the bcs.
to solve that problem just cap that vaccum hose and get vaccum from any other source.
to solve that problem just cap that vaccum hose and get vaccum from any other source.
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mn12sc35th
Registered User
What turbospeed has labeled is the bypass valve and they tend to get stuck.
BCS's were used on the TurboCoupes and were an electronic boost limiter. I have yet to see it mentioned in either the 89 or 90 electrical manual so I'm pretty sure our cars didnt have them.
If you can get to it and spray it good with something like WD-40 it should loosen up.
It sounds like that could be your problem (it is a common one...). You can try unplugging it and seeing if that brings back your boost.
BCS's were used on the TurboCoupes and were an electronic boost limiter. I have yet to see it mentioned in either the 89 or 90 electrical manual so I'm pretty sure our cars didnt have them.
If you can get to it and spray it good with something like WD-40 it should loosen up.
It sounds like that could be your problem (it is a common one...). You can try unplugging it and seeing if that brings back your boost.
stocker 89
Registered User
On the 89
That vac line goes to a EEC controled vacume solinoid. Some call it a super charger boost solinoid. If the solinoid is bad the VlV won't open.
That vac line goes to a EEC controled vacume solinoid. Some call it a super charger boost solinoid. If the solinoid is bad the VlV won't open.
mn12sc35th
Registered User
I double checked the 89 EEC Schematics and there it was 
It didnt list the exact location of it though....
It didnt list the exact location of it though....turbospeed
Registered User
most 89's and them and some 90's mine does but other ones i have checked dont.
mn12sc35th
Registered User
I can't remember if your cars auto or 5-spd turbospeed... that may have something to do with it for 90 (like the egr did...) I can't remember if mine does or not but hell the car itself is 2500 miles away for now so I can't check
turbospeed
Registered User
so did it worked?