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Discussion Starter #1
I just purchased a 1999 Saab 9 3. When the turbo spools completely it is into the red area of the boost gauge and the fuel cuts out. If anyone has any information on why this is happening I would greatly appreciate it.
 

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it definitely has to do with your boost control system which causes fuel cut when the ecu reads about 15.5psi which is probably happening when you go in the red.
check all of the lines going to and from the apc solenoid located next to the radiator on the passenger side. there should be three of them: one on the intake pipe to the turbo, one on the compressor housing and the third goes to the wastegate. if these are all connected properly, it may be the solenoid isnt working right or even check to make sure the solenoids electrical connector didnt fall off. hope this helps.
 

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Discussion Starter #4
as far as I know the car is completely stock, I will have to check all the hoses and I will post on here whether or not the lines are off. Thanks
 

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Sounds like a seized waste gate. Happened with me. You can spray the crap out of it with a Heat Rising Lubricant. You have to take the DP off though. Worked for me, havent had fuel cut in over a year now.
 

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ParaMedic_Saab said:
Sounds like a seized waste gate...
That is a possibility, but the most common cause of overboost followed by a fuel cut on our cars is a clogged or failing BPC (Boost Pressure Control ) valve. In some cases, all you have to do is blow the crud out with shop air, or a can of compressed air.

You can diagnose this by bypassing the BPC (meaning, take off the compressor and wastegate actuator hoses, and connect them to each other.
The turbo should get to only base boost.

If the overboost is gone, the problem is in the BPC.

If the overboost/fuelcut is still there, the problem is in the wastegate or actuator.

Welcome to the forum, new93!
 

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I am having a similar problem

I'm sorry for hijacking your thread but I am having the same problem on my 1999 9-3. I have tried disconnecting and even bypassing the apc solenoid and it still is cutting out. It is supposed to have base boost when the solenoid is disconnected, i thought, but it still produces full boost. That has led me toward the waste gate or wastegate actuator. The solenoid appears to be functioning normally.

Is it more common to have a sticking wastegate or a faulty waste gate actuator. Is there some procedure for checking the functionality of either the gate or the actuator?
 

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bchicoine said:
...It is supposed to have base boost when the solenoid is disconnected...
That is usually true, and it was, in my case.

However, the only way to take the BPC valve completely out of the picture is to connect the compressor directly to the wastegate, and make sure that any hose or hoses used are not plugged up or broken.

One way is to unplug the two hoses (Compressor and Wastegate) from the valve, and connect them together using a small 2-way hose connector you can get at any autopart store or hardware store. Another way is to unplug the hoses from the compressor and wastegate, and connect them using a piece of new hose.
 

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PMI said:
One way is to unplug the two hoses (Compressor and Wastegate) from the valve, and connect them together using a small 2-way hose connector you can get at any autopart store or hardware store.
This is how I have it isolated right now.
 

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bchicoine said:
This is how I have it isolated right now.
Hmmm, sounds like the waste gate actuator and arm would be the next step. I think you can test that using a vacuum pump, the kind that can be set up to make pressure or vacuum, and check the base boost. I think you can get one from Autozone, loan tool program.
 

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Discussion Starter #11
Well since my car still had its 3 month, 3000 mile warranty on it, I took it into the dealer and they had fixed it. They had told me that my waste gate acutator arm was seized so they took it out and cleaned it and greased it and now my car runs perfectly.
 

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new93owner said:
Well since my car still had its 3 month, 3000 mile warranty on it, I took it into the dealer and they had fixed it. They had told me that my waste gate acutator arm was seized so they took it out and cleaned it and greased it and now my car runs perfectly.
Hate to say I told you so. Its becoming a very coming thing with our cars, according to my mechanic. Luckily its an easy fix.
 
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