Hey guys, I have an ‘04 gsr. It has some mods that I will list below. My problem specifically is no boost pressure through most rpms until around 7k where I get maybe 6psi. After reading through other people’s posts around here the three most common issues are as follows: clogged cat, wastegate actuator malfunctions, turbo gone. I believe my problem lies somewhere in the wastegate actuator. The turbo still spooks and produces so I’m sure that isn’t the case. Also I have no cat so that can’t really be an issue either. The problem occurred after a few hard pulls and the car was parked, upon starting it again it drove perfectly fine besides the lack of boost. I have another car so I parked it and plan on taking it apart to fix it myself. But this being my first issue, I figured maybe a 4G63 vet could give me a pointer or two. Main question is, how do I go about testing to see if it’s the actuator failure? If I need a new one, what’s your suggestion on replacement brand?

mods list:K&N Dry Cone Filter with 4" adapter

Stock MAF

FP Intake Tube

FP RED/Black JB Turbo 10.5 Ceramic Coated Housing w/18lbs wastegate

FP SS Oil Feed Line w/Filter SS Water Feed Line

GrimmSpeed 3 Port Boost Solenoid

Agency Power 2.5" Charge Pipe(LICP)/Black Ceramic Coated

ETS 24"x11.5"x3.5" Bar & Plate Core Intercooler

Stock UICP with upgraded hosing/clamps/Black Ceramic Coated

Forge BOV w/Blue Spring

Skunkworkz/Skunk2 Fully Custom Ported 68mm Throttle Body

MAP Rev 3 Modified Intake Manifold Black Ceramic Coated

FP Racing Manifold Port Matched Black Ceramic Coated

Custom Black Ceramic Coated Heat Shield Note: for sale in other thread, will include if you want it

Map SS 02 Dump Housing w/Vband clamp to downpipe

Map SS 3" Downpipe

Perrin high flow 3" cat

Custom JDM 3" Catback piping with AERO Turbine Muffler

Haste Triple Core Race Radiator

Mishimoto Slim Line Fan w/factory fan control circuit

Custom 1 off Oil Catch Can with Remote Breather

 

Try the following in sequence to find the culprit:
1. Pull the intake and check the turbo shaft turns freely and has minimal side-to-side and in/out play. This should tell you quickly if your turbo is blown.
2. Run a boost leak test to check your cold side circuit for pressure losses. This will find any holes that your boost pressure is leaking out through.
3. Connect a bicycle pump to the actuator pressure hose to see if it moves. If it moves OK then it could be a hot side problem.
4. Pull the exhaust and O2 housing to get a look at the flapper valve and the turbine vanes for any physical damage.

Good luck tracking it down. Let us know the outcome.

 

Sounds like your wastegate is stuck open. If you have an internsl wastegate, use long pliers to grab wastegate arm and push & pull on that flapper arm. The wastegate should be pulling it hard where it doesn't move. If you can pivot the arm, then you need to tighten it. Who installed you wastegate & how much tension was it installed with?

 

thank you for the guidance. I’ll have it apart sometime this weekend to get down to business.

 

the wastegate was installed by the previous owner who put the FP turbo setup on it.

 

It honestly sounds like the wastegate flapper arm fell off. I had that problem once, same symptoms.

 

Pictures will help.

 

fell off? Dang, I hope that’s not the case.

 

Snap a picture right behind radiator. We should be sble to see the wastegate arm.

 

i'm in agreement with the above that something must be up with the wastegate and it's connection to the flapper. If you're only getting some boost up top it sounds like the flapper is stuck open and only when the turbo is flowing near peak capacity do you get enough back pressure across the open flapper to generate some pressure.

 

Got off of work early. I’ll get some pictures up when I get home.

 

 

 

After getting some parts out of the way and toying with it. It was jammed. Now it freely moves up and down. I can wiggle it by hand. It feels like it can get stuck again easily though. Is there something I should tighten? Isn’t this arm supposed to already have tension on it?

 

Video evidence coming