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APC system STILL doesn't work HELP!

1315 Views 14 Replies 4 Participants Last post by  synoptik
I still can't figure out what the problem is with my APC system. It just doesn't want to allow anything over basic boost. I recently bought a complete APC system that came off of a working 89' Saab 900 Turbo, just like mine. I have fitted everything I got from the other car and it still didn't want to work. I currently have a MBC connected and I don't like it (boost is all over the place) but I can't figure out what the problem is with the APC. The wastegate works great and holds pressure when the vacuum line was disconnected. The only visible problems I have noticed is that the seat belt light blinks because the fuse was pulled (passive seat belts don't work) and someone removed the housing for the oil filter and replaced it with the N/A housing so I can't connect the oil cooler to the engine. I can't think of anything else to do or what it could be! The APC solenoid will click when turning on the car as well as when I apply the brakes. I get a series of clicks when tapping on the knock sensor. I have two of everything related to the APC system and have replaced everything and still nothing. What else could cause it to run in base boost????? What color are the wires that go to the boost sensor under the dash?
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synoptik said:
.... charcoal canisters
Is that the same as the vacuum canister?
You cant look after the solenoid if its fully open at idle. It is on boost you need to know! Lets say the solenoid is open on off boost and when there is comming boost, the solenoid have to close. The systen works like when there have to come more boost, the solenoid have to close, if there could be knock or something else, the solenoid have to open in a short time!

The more pressure that goes in the wastegate actuator = Less boost
If you take off the hose to the wastegate, the turbo will boost all what it can! = No pressure in the wastegate actuator!
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