Lots of power and fuel cut. Pretty sure something's broken.

I've recently put on an Injen CAI and Corksport intercooler hoses. I don't think that's the problem but it's probably worth mentioning.

The car feels like it has a lot of power in the past couple of weeks. It was hesitating a bit during acceleration so I moved to one step cooler spark plugs and that fixed the hesitation, but there's still a fuel cut problem.

The car is boosting to 9-10 PSI and at about 9, I hit fuel cut. Aside from the previously mentioned intake / hoses, this car is all stock, so I expect it's overboosting. I also get a random CEL that goes away after a little while (I haven't read the code yet).

A few years ago (2008 or so), I had the WGA replaced under warranty when it was doing something like this. I suspect the same thing is going on now.

So, is there any way to check this? I.e., to check the WGA before I replace it? Is the ATP 6psi one still the one to get if that turns out to be the problem?

It's possible the intake raised the boost a tad and you are hitting fuel cut in cold temps. I would switch back to NGK ZFR6F plugs, colder plugs are only necessary once you hit over 15psi or so but I do believe new plugs helped the hesitation if you needed them. To check the WGA just pull the vac line to it and blow into it. If it holds air it should be alright, if air passes through the diaphragm is broken. And pull that CEL code asap just in case

I haven't been able to pull the code yet because I can't find my obd cable but the WGA is definitely toast.

Do you have any recommendations for a replacement?

I've found three of them that should get the job done, but all at varying prices and with mixed feedback.

1. ATP 6PSI actuator. Said to run at 8psi or so on this car (fine by me). It's cheap but I've read in places that they need frequent replacement (similarly to the OEM one).
2. Forge. Seems to be about $150 but again, mixed reviews. Some say it's great but others have reported problems with boost spikes.
3. Turbosmart IWG75. 7psi application-specific. It would probably cost in the $180-$200 range. I can't find any reviews on this one.

I have a boost gauge and don't mind doing a little adjustment. I don't intend to go over 8psi, regardless of the WGA I choose. The fuel cut happens around 9-10 so I definitely want to stay under that. I don't have the time or resources for a rebuild so I'd like to keep from blowing up this engine.

The only future mods I have in mind would be to increase stability and longevity. Maybe an AFC and / or SMIC (basically the stuff in the MSP daily driver thread, but without trying to actually add boost).

I have heard good things about the turbosmart, I had the Forge and it spiked on my car, I don't recommend it. Now I run the ATP stock style and it runs great.

How long have you had the ATP on there? I seem to be replacing WGAs every 50k miles and it's getting old.

I like that the Turbosmart has a replaceable diaphragm. That way if it eventually does fail, I can just open it up and it's fixed for $35 or so.

I've ran it the past few months, I didn't think they failed that often. Then again it takes me a few years to hit 50k miles so it's not a huge deal. You can put a vacuum check valve on the wga line to help it last longer

So then something to ensure the WGA only gets positive pressure? The install manual for the Turbosmart says that's a requirement for theirs and the factory line that's hooked up looks like it might see vacuum as well since I think it's hooked up to the same set of hoses that my boost / vac gauge is.

I guess my concern there is if I put a valve in that only allows positive pressure, won't that essentially blow up the diaphragm like a balloon? And if I put a valve in that releases that pressure, would that cause other problems?

I really should learn more about turbos.

The check valve is to prevent the WGA from seeing vacuum, some people believe the vacuum pulling the diaphragm the opposite way damages it over time. I don't know how accurate that theory is but the check valve will probably help it actuate quicker.

I ended up going with the Turbosmart along with a Boostvalve G2 as a check valve. I chose the Boostvalve specifically because they addressed my concern about relieving the built up pressure in the wga hose.

I'll post back here once everything's in and I've had time to set it up.

I finally got everything installed. It is a serious pain in the ass to replace the wga with the turbo on the car. I spent easily an hour just trying to get the circlip back onto the clevis at the end.

Also, the Turbosmart wga is bigger than oem which made getting it in the bracket a little tricky. I had to spray some penetrating oil in the clamp that holds the oil and coolant lines. In order to make clearance, I had to rotate that clamp out a bit to make room to put in the new wga.

The new wga works great. Boost goes to 7 and just stops. No spikes or creeping. I have the boost valve set way lower than 7psi for now so it's just working as a check valve and maybe helping with spool time.

Unfortunately I'm still getting some fuel cut when the engine is cold. My vac and boost levels look right so I'm going to try cleaning my MAF or trying my backup.