Wastegate Actuator Operation - 87 300D

[Jmana]

I have a feeling my wastegate is stuck open. I have very little power, at least until I get up to around 2,500RPM, and because of the poor power it takes forever to get up to that point. I took the ALDA off months ago, so I know it's not a bad switchover valve or ALDA. The thing that makes me think the wastegate is stuck, is that I can't seem to move the lever that goes between the actuator and the gate. I've only been able to get it to move maybe a millimeter, of course I can't put much force on it because it's not exactly easy to get to. Is there a way to test both the actuator and wastegate without taking the turbo off first??

[sixto]

You can't move the actuator lever by hand. It has a big @$$ spring holding the wastegate flap closed against exhaust flow.

Apply metered pressure to the actuator and see at what point it moves. It should be fully open somewhere between 10 and 14 psi. Some MityVac units have a pressure mode and pressure range in the gauge, others have a relief port use can use as a pressure source. You'll have to tee in a pressure gauge.

There's a circlip keeping the actuator arm on the wastegate lever. Disengage the arm and see check that the wastegate lever is in the fully closed position in the neutral position of the arm.

If that all checks out, I'd guess either the wastegate flap is off center or the flap has disintegrated.

Before you pull the turbo, check how much radial and axial play there is at the compressor end of the shaft. If there is any axial play, the turbo is shot. If there is more than 1/8" of radial play, the turbo could be tired and not spinning freely, thus taking longer to spool.

IIRC you should see the compressor spinning at idle so that's one way to check that it's spinning freely.

Of course you should check that the fuel filters are clean, etc.

Sixto
87 300D

[Jmana]

The turbo blades are nice and tight, and seem to spin freely so I assume the turbo is good. And all filters are new so that's not the issue either. Where do I hook into the actuator to apply pressure? Is it where the rubber hose goes in the lower part?

[sixto]

I don't know about lower part. It's the opposite end from which the arm extends.

Sixto
87 300D