Originally Posted by paull
Thanks for the tip, I took the car into a shop in town that specializes more in tuned cars, here is what was found:
They checked for boost leaks but the car was actually fine there. What they did notice was the Mass Airflow sensor was not mounted properly (too long of bolts). I bought the car as rebuilt status last year and the guy that fixed it up initially probably did this (he did a few sketchy things). So the shop fixed that issue and test drove it and found that if the car hits 5000 RPM it limits the RPM and a CEL comes on for the turbo wastegate sensor not functioning properly (or something to that effect). They replaced that part, but the same RPM/CEL issue still occurs.
They did some online digging and suspect that there may be a glitch with the generic tune I gave it (Gabedude's A8DK100X - MY07 WRX Stage 1 - R29) for my particular car. They suggested I buy a Cobb AccessPort which comes with a more reputable stage 1 tune and go with that. In he mean time they suggested reflashing with a stock tune and don't drive aggressively until then.
So that's where things are at currently. They fixed a couple of sensors which is good but I now have this CEL at 5000 RPM issue which may or may not be fixed by a different tune. I'll have to save up for a bit for that AccessPort if that's the direction I decide to go, but ~$1000 CAD is a big price to pay for something that may not even work. It's times like these I wish I lived in a bigger city where I can go for a pro tune!
Doesn't sound like your shop specializes in Subies.
Sounds like what you're saying is that as you go and accelerate hard the car spools up and then above 5k rpm just hits a wall of power. Does it feel like there's a hard drop in power? Like you're hitting a wall? And is the code Wastegate Solenoid Performance too High? It's P0244 I think.
If so, you have a boost control issue (obviously) and are hitting the overboost condition. It's not a boost control solenoid issue but either the plumbing of the vac hoses to the solenoid/wastegate OR spring pressure on the wastegate actuator OR missing restrictor pill in one of the lines.
First, the simple check. Visually inspect the boost control hoses and make sure the restrictor pill is there by squeezing the vac hoses and that it's on the right hose.
Here's an article about how the boost control on our cars works:
If all is good here, put the factory map back on and see if you continue to overboost. If so, it is most likely that someone adjusted the wastegate actuator arm (I'm assuming your car is running the td04 turbo (stock on your year)... and you said Stage 1 so.
The good news is that most fixes for this are cheap. The one blatantly annoying situation is if someone has adjusted the arm. If so, you're going to have a headache and will either have to get a replacement actuator (from the same turbo), a protune, or keep adjusting it back and forth (keeping track of how far you have gone) until you find where it was set to from the factory.
Tip for anyone reading this: NEVER EVER adjust the wastegate actuator for ANY reason. It does NOT serve as a way to compensate for boost control error. It also breaks the relationship between wastegate duty cycle numbers and the actuator movement in a non-linear and totally unpredictable way rendering any off the shelf map useless.