fastfamilywgn

MY 02 WRX Wagon is dropping/surging boost. Each fix the dealer has tried had made it better but not eliminated the issue

Was has been done:
no mods to car
(oem parts replaced by dealer)
Downpipe (cat wouldn't let light through) 38500mi
Uppipe and EGT sensor (dealer said cat was loose but not clogged) 39700mi

Each of these parts made the car run better without boost and boost faster above 3000rpm but when peak boost was required (floored below 3000rpm) it will release just as it comes up to pressure at ~3000rpm. (first noticed under hard acceleration in 3rd WOT. four surges between 3000-6500rpm) They checked the stock bypass valve and about every other thing under the hood that is related; said it is all ok!!

Supposedly the MAF sensor reading goes crazy when the problem occurs.

Ohh yeah never had a CEL!!

Today the tech drove my car with the wastegate controller disconnected. They told me that the problem did not occur and that it was very smooth boost. Now that they reconnected the boost control the turbo will hold pressure for a bit but still release, much better but the problem is not solved. Why did it get better?

The hesitation/resurge can still be felt even at 40-50 mph in 4th at 1/2 - 3/4 throttle.

My question is :

Is it my wastegate or is it the boost control?? or could it still be something else entirely?? any ideas greatly appreciated!!

Thank god this a certified pre-owned but god I wish I knew what the previous owner did to this car!!! I bought it at 35102 mi!! in Feb!!

testes1010

there's a pill(restrictor) in the lines going to the wastegate solenoid...if the previous owner had used some other form of boost control this pill maybe missing....if missing it could cause some strange symptoms....

I assume the tech reset the ecu after each part change otherwise it would take a while for the ecu to relearn...

Imprezer

iTrader: (9)

Yeah, I bet its the pill too...

fastfamilywgn

No I checked that as soon as I read about it in another forum. It matches the diagram I printed out from there exactly. It seems like the orfice is on the proper side of the "T". The Subaru tech said he checked all the lines and they're clear of obstructions too.

They have reset the ECU a lot. Every part and after every inspection.

THe only clue I have from the previous owner (or dealer) is that the cruise control cable was routed under the intake instead of above. Telling me that somebody had put it back together and wasn't paying attention! I corrected this before I even made it back to Oregon from Texas with it because the cruise was a little jerky.

fastfamilywgn

I was thinking its probably the solenoid after reading some nasioc threads.
Does anybody have first hand experience with a failing boost control solenoid??

I was thinking it just wouldn't work but I guess it could probably do funny things like what I'm experiencing.