Wastegate regulator bypass valve -N75- Questions - a real brain teaser
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AudiWorld Senior Member
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Wastegate regulator bypass valve -N75- Questions - a real brain teaser
Allright everyone, here is the problem:
My car hesitates during full throttle acceleration and then at about 3500-4000 rpm it stops hesitating and runs like a champ. I posted a bunch of data logged from Block 115 (the link is in the original message) which shows this problem. I do NOT have the symptoms of a torn TBB or F-hose (though I have checked both of those) and the recirc valves are fine (though they would not cause this problem and they have been checked as well). At highway speeds and under slow acceleration the car seems fine. No funny noises, etc. The car goes in for the second time for this on Monday for a pressure test of the intake system.
The only thing that I can think of (after tallking to a number of Audi tuners) is that the Waste gate regulator bypass valve is soemhow causing the problem. Any ideas???? Unfortunately VW-tool does not allow the output test procedure to allow me to check the selenoid dircectly (tried it last night, apparaently it is an a problem with Vw-tool, VAG-COM won't have theis capability for a month or so). I am trying to gather as much info as I can to *cough* help the dealer solve this problem.
I would relly apprecaite any thoughts people have on this problem.
BTW, the car is stock except for a K&N filter and Borla exhaust.
For a discussion of the Wastegate regulator bypas valve - go here https://www.audiworld.com/forum/m.new/s4/msgs/66834.phtml<ul><li><a href="https://www.audiworld.com/forum/m.new/s4/msgs/164328.phtml">Original post and links to data</a></li></ul>
My car hesitates during full throttle acceleration and then at about 3500-4000 rpm it stops hesitating and runs like a champ. I posted a bunch of data logged from Block 115 (the link is in the original message) which shows this problem. I do NOT have the symptoms of a torn TBB or F-hose (though I have checked both of those) and the recirc valves are fine (though they would not cause this problem and they have been checked as well). At highway speeds and under slow acceleration the car seems fine. No funny noises, etc. The car goes in for the second time for this on Monday for a pressure test of the intake system.
The only thing that I can think of (after tallking to a number of Audi tuners) is that the Waste gate regulator bypass valve is soemhow causing the problem. Any ideas???? Unfortunately VW-tool does not allow the output test procedure to allow me to check the selenoid dircectly (tried it last night, apparaently it is an a problem with Vw-tool, VAG-COM won't have theis capability for a month or so). I am trying to gather as much info as I can to *cough* help the dealer solve this problem.
I would relly apprecaite any thoughts people have on this problem.
BTW, the car is stock except for a K&N filter and Borla exhaust.
For a discussion of the Wastegate regulator bypas valve - go here https://www.audiworld.com/forum/m.new/s4/msgs/66834.phtml<ul><li><a href="https://www.audiworld.com/forum/m.new/s4/msgs/164328.phtml">Original post and links to data</a></li></ul>
AudiWorld Member
Joined: Aug 2000
Posts: 127
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Re: Wastegate regulator bypass valve -N75- Questions - a real brain teaser
Do you have an external boost gauge? This would serve as a redundant system if your car's ecu is reading the wrong numbers. You may be loosing boost due to pressure leaks or the wastegate opening prematurely under 3500rpms.
Once you've identified that you'll know if its a boost problem or other (eg: ignition, timing, etc)
Good luck.
Once you've identified that you'll know if its a boost problem or other (eg: ignition, timing, etc)
Good luck.
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