HELP ! Major Boost problem (No Boost) at all
03-07-2003, 11:30 AM
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HELP ! Major Boost problem (No Boost) at all
Driving back from a CT funeral today.. Left a rest stop on the Jersey Turnpike and I jumped on it pretty good.. I remember saying to myself WOW, this has never run stronger and then BOOM, snork, chuck, chuck, stumble and no power.. My first thought was "must have blown a hose off".. I pulled over and looked.. Everything was where it belonged.. It isn't the same feeling as when the DV hose blew off... Then there was no power and a LOUD hollow SSSHHHhhhhhh sound.. This time I hear the turbo spooling up, NO leaking hose hiss at all. The boost gauge will not move past Zero.. I made it back to Frederick, I just took it real easy.
Could I have over boosted and the computer put me in limp mode? What's odd is I got no CEL light at all.
The other part of the mystery is this. Since installing the new Upper IC hoses, the ESP light will come on everytime I first start the car and will come on with a mind of it's own sometimes after that.
Me thinks I need a VAG Com ASAP !
Any thoughts ???
Could I have over boosted and the computer put me in limp mode? What's odd is I got no CEL light at all.
The other part of the mystery is this. Since installing the new Upper IC hoses, the ESP light will come on everytime I first start the car and will come on with a mind of it's own sometimes after that.
Me thinks I need a VAG Com ASAP !
Any thoughts ???
03-07-2003, 11:47 AM
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If the turbo is spinning, it's either an open DV or an open wastegate.
If it's an open DV, you will still have some boost, but not much. I'd bet the wastegate is open.
If it's a bad N75, is should show up with the VAG. If it's mechanically stuck, it won't.
If it's a bad N75, is should show up with the VAG. If it's mechanically stuck, it won't.
03-07-2003, 11:49 AM
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When you pulled over, did you shut your engine off? If it were an overboost situation, shutting off
the engine will reset the ecu. You will then have boost again. Sounds very much like a leak some place. You don't have to "hear" something swooshing. A VAG will definitely help you diagnose your problem. My friend had the cap of his DV slightly loose, this was causing him to go into limp mode. screwed the cap back on, tah dah! All fixed.
Have you restarted your car since the incident?
Have you restarted your car since the incident?
03-07-2003, 12:18 PM
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No boost with no CEL or fault codes points to a waste gate failure where the gate is stuck open. The
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Waste gate is cast into the exhaust side of the turbo housing and has a trap door style valve that when open prevents boost. It is actuated by a spring loaded lever arm and shaft that are moved via a vacuum chamber controlled by the NC75 valve. This mechanical mechanism can break (it happened to my A4) you can tell if it is in fact broken by getting a long (I mean long) needle nose pliers on the shaft and trying to move it. In the pic you cab see the waste gate door and on the turbo to the left the end of the shaft @ 3 o-clock with red paint mark. If it is loose and moves from side to side easily, then it is broken. The fix is to replace the turbo. Keep in mind this may be not even close to what is wrong; based on what you said it could be. BTW this type of mechanical failure kicks out no fault codes.
Waste gate is cast into the exhaust side of the turbo housing and has a trap door style valve that when open prevents boost. It is actuated by a spring loaded lever arm and shaft that are moved via a vacuum chamber controlled by the NC75 valve. This mechanical mechanism can break (it happened to my A4) you can tell if it is in fact broken by getting a long (I mean long) needle nose pliers on the shaft and trying to move it. In the pic you cab see the waste gate door and on the turbo to the left the end of the shaft @ 3 o-clock with red paint mark. If it is loose and moves from side to side easily, then it is broken. The fix is to replace the turbo. Keep in mind this may be not even close to what is wrong; based on what you said it could be. BTW this type of mechanical failure kicks out no fault codes.
