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Just throwing this out there because I haven't read this thread - but if PCV system hasn't been mentioned, a blown "tee" hose can steal some boost and cause delay in building boost. It's under the intake manifold. A silicone replacement from 034 is cheap.
HI and thanks for the suggestion. I know there were all whole bunch of hoses that were replaced when I started this journey but not sure it the PCV was one of them. I will surely check on that and report back.
Hi Dave. Hope you are well. Been a while since I did any work on the car, so in case anyone is interested here is where I left off:
1. Only getting 10 to 12 psi boost thus power is down accordingly.
2. CEL still there but shuts off with a quick blip of the throttle. CEL comes
back say 10 seconds after blip, sometimes longer.
3. The installed adjustable FPR has kept the fuel pressure down to 58 to 59 psi.
4. Idle is hunting when engine is warmed up. The hunting is disguised slightly
by applying load like switching on the air conditioner. Switch off the airon and
the hunting becomes irritating.
Here's what happened yesterday:
1. Found an old but still new aluminum bypass valve. Installed it and immediately
felt the power come back. I can consistently hit 20 to 21 psi of boost. Strangely
I hear a honking sound like a duck as boost builds up.
2. The CEL is still present and acting as it did before.
3. Installed an original fuel rail based FPR just to see what would happen. Result was
fuel pressure rose back up to 70 psi. Idling became very rough with black smoke.
Reinstalled the adjustable FPR and engine ran as before.
4. Idle hunting still there.
Really can't figure out what is causing high fuel pressure when using the original FPR set up. Same goes for the idle hunting. The engine idles well when cold but the hunting begins once warmed up. Any advice fellows?
Hi Dave. Been a while since my last post but may having to share with you and other members.
Had another mechanic look into the problems of 00537-code and part throttle hesitation. After a few test runs the mechanic went straight to adjusting the TPS and a silver colored adjustment screw under the throttle body spring. Please refer to the photo below to see the adjustment screw. He referred to his action as aligning the throttle body.
While adjusting the TPS and screw the check engine light would extinguish. We were also able to clear the fault code using the VAG tool. The car ran perfectly for several kilometers before the check engine light came back on and the engine started going back to its old ways. He would adjust again, and again the car ran perfectly for a few kilometers and then reverted back to the check engine and part throttle hesitation. We went through this cycle at least four times and we consistently experienced very good running each time.
The mechanic checked the throttle blade shaft and found that it had a very noticeable play. He claimed that this play was causing his adjustments to go off and also contribute to unmeasured air leaking into the system. Assuming he is right (and he sure seems to be), is there a way of fixing the play in the shaft say by replacing bushings if ever?
Hope you and others can provide input. Thank you
If you have play in the shaft bushings then you might need a good used UrS4 or UrS6 throttle body. Barring that, it might be possible to replace the bushings with something that would take the shaft end play out.
12-09-2013, 10:35 PM
