WRX Problems

Hello Everyone


Its been a while since I've been on the boards posting, but have been reading them the whole time.

Anyhow, My baby is sick...yep really sick.

Here's my question:

I noticed last night the the car has been lacking some power..it was really late and I was really tired when I noticed it, so I left it alone and went to bed. this morning on my way to work I noticed that when I'm on the throttle the boost pressure goes up and then down...up and then down...kinds like im on and off the throttle, but im not the pedal is floored, but the boost goes up an down...its really pissing me off, and I just wanted to know what could be causing it, or if anyone here has had the same issue?? OH, btw..the car also makes a tingly scratchy noise comming from the turbo charger when on idol too.

Any help or suggestions would be appreciated.

In case your wondering its a 2002 wrx...CAI, 3"cat back, and blow off valve.


Thanks Eveyone.


Scooby Doo

boost leak? Pre-turbo exhaust leak? Sticky BOV or wastegate maybe?

I took off the blow off valve last night, and took it apart, cleaned it and placed it back on the car at the hardest setting, but I still have the same issue. Im not too sure what it is, but I know its not normal. I used to be able to have the boost pegged from 2nd gear and up before this problem, and now I loose like 4 lbs of boost in all gears, but from 4th gear to 5th..I still have the up and down problem.....WTF this is really starting to piss me off. I booked an appointment with the dealership...I still have the engine and drivetrain warrenty on the car...do you think it will be covered...I know who knows...one thing is for sure...Ive kept the boost stock since I first bought the car, so i wont give up without a fight.


Any more suggestions would be appreciated...I keep you posted on the updates...hmmm im almost thinking...wy not buy a new turbo and turbo xs ecu...that should fix the problem.


Scooby Doo

Try replacing the bypass valve. Eliminating the BOV as a cause would be my first priority. Its an 02? Take it to the dealer.

I dont know any of the specifics of the waste gates on WRXs, but those are symptoms of a wastegate problem. That is the firt place i would check. In the worst case situation, you could have a problem with the turbo itself ( bad bearing, bent compressor blade, etc.) though that doesnt really explain the bootstrapping.

Here is something i found from an airplane page but everything on it pretty much applies to cars:

Unstable manifold pressure gauge ( bootstrapping ). Fluctuating MP
1. Plugged fuel injector nozzles.
2. Dirt in fuel manifold.

3. Faulty differential or density controller.

4. Sticky wastegate or bad pressure controller. Lubricate the wastegate butterfly shaft and move the shaft back and forth. If the wastegate shaft squeaks then it is probably sticking when hot. If the manifold pressure increases immediately upon airspeed increase, then the most likely suspect component is the wastegate. For Cessna aircraft the Maintenance manual has a detailed procedure to determine if the engine is bootstrapping (unstable manifold condition). Refer to the engine section under "Turbocharger Operational Flight Check Procedure".

5. Lycoming TIO540 -C1A engines-Inspect for compliance with Lycoming Service Instruction 1396, incorporation of new induction air housing.

6. Incorrect (wrong pressure) spring on wastegate actuator.

7. Continental TSIO360 -MB. Improper torque on the retaining flange that secures the induction tube to the cylinder head. Reference Continental Service Bulletin M87-4 or latest revision.

8. Fluctuating oil pressure on turbocharged engine causing fluctuating oil pressure to wastegate. For Lycoming TIO-540 engines refer to latest edition of Lycoming Service Instruction 1279.

9. Hydraulic lifters malfunctioning. Check for magnetism.

10. Turbocharged engine - change brand of oil. Controllers are oil actuated and different oil have different viscosity characteristics that might effect controller action.

11. Turbocharged engines with pressure magnetos - Magneto leaking too much air.

12. Hot air being ingested into the engine. Cessna T206, T210, P210 are sensitive to air leaks from inside the engine cowling which results in hotter air entering the engine. Performance is decreased and bootstrapping occurs at a lower altitude.

13. Intake valve sticking. Causes the MP to dance!


Don't give in and take it to the dealer.