Testing Wastegate Actuator TD04

How can the wastegate actuator be tested on a Mitsubishi TD04 turbo? Stock on a '93 940 with the integral CBV mounted vertically (same as below except for the CBV).

Problem is that the turbo won't pressurize up. It happened after I replaced the seal and gasket on the drain pipe on the turbo, which I removed/replaced the wastegate actuator rod from the wastegate shaft to access the pipe bolts. Didn't adjust the rod, just removed/replaced it.

Engine drives fine (no smoke, has power - no turbo power). Turbo gauge doesn't pass the mid-point, but show vacuum as it would normally through driving conditions.

So far checked-

-The wastegate shaft moves freely (the actuator arm is on the engine side of the shaft - I don't think it's possible for me to have put it on wrong -it's same as pictured below)
-The actuator valve holds vacuum
-Took off the hose from the wastegate actuator to turbo housing. The car drove the same (no turbo power). (replaced hose with new)
-Took off the hose from the air filter housing to front of the turbo housing. The turbine spins freely, there is some play in the shaft.
-Checked the CBV - opens easily with vacuum applied.
-Checked vacuum ports to see if they were plugged as I removed hoses as I went through them. All were not plugged.



So since I only messed with the actuator valve before I started having the no pressure problem, I would like to test the actuator valve. Do I need to apply vacuum or pressure to the valve to get it to move the wastegate? How much vacuum/pressure is needed to get it to move the wastegate (I don't want to damage it if it's not the problem)?

Pressure moves the valve...duh...and you will see it start to move with the slightest amount of presure and should be fully open by 7 or 8psi. I like to use a football pump hooked to a boost gauge and the wastegate so you can slowly apply pressure and see when it's opening.

Have you checked for boost leaks and checked the turbo itself making sure it's not borked up? Basically checking for lateral and axial play (grab wheel and jiggle and all directions)

Secondly what do you mean about the cbv facing up? Did you do that at the same time as when it started messing up?

Canadan said:

Pressure moves the valve...duh...and you will see it start to move with the slightest amount of presure and should be fully open by 7 or 8psi. I like to use a football pump hooked to a boost gauge and the wastegate so you can slowly apply pressure and see when it's opening.

Click to expand...

Good - Pressure activates the valve. That's what I thought. I like the football pump method.

Canadan said:

Have you checked for boost leaks and checked the turbo itself making sure it's not borked up? Basically checking for lateral and axial play (grab wheel and jiggle and all directions)

Click to expand...

I assume you mean check to see if the hoses/IC are cracked/leaking. I've inspected them, and all seems to be in shape, I don't hear anything leaking and car idle fine (~700 rpm with little variation).

I did check the play in the turbine shaft->

-Took off the hose from the air filter housing to front of the turbo housing. The turbine spins freely, there is some play in the shaft.

Canadan said:

Secondly what do you mean about the cbv facing up? Did you do that at the same time as when it started messing up?

Click to expand...

I didn't say that the CBV is facing up? I did state that it's an earlier TD04 with the CBV mounted vertical and not at an angle like the later ones. Here's mine:



I didn't touch anything with the turbo except removing/replacing the WG actuator rod before the no pressure problem. Turbo pressurized up like normal before I touched the WG actuator rod. Since then I did remove the CBV and applied vacuum to it, and it moved easily and held vacuum.

I'm going to remove the WG actuator and test it out of the car.

Paul

as for boost leak testing i mean make a boost leak tester ( google it, some pvc, and a tire schrader valve/ air chuck is all it is) to ACTUALLY test for leaks. when you say there is some play in the turbo, how much? guestimate you best in either mm or inches, side to side play (iirc less than half a mm) is okay but in and out play is no bueno. excuse me about you cbv i was slightly confused i thought it was something you modified, btw did you check the cbv diaphram for leaks?

Sounds like the clip or pin holding the actuator to the wastegate fell off, leaving the wastegate to flap in the wind.

Canadan said:

as for boost leak testing i mean make a boost leak tester ( google it, some pvc, and a tire schrader valve/ air chuck is all it is) to ACTUALLY test for leaks. when you say there is some play in the turbo, how much? guestimate you best in either mm or inches, side to side play (iirc less than half a mm) is okay but in and out play is no bueno. excuse me about you cbv i was slightly confused i thought it was something you modified, btw did you check the cbv diaphram for leaks?

Click to expand...

CBV holds vacuum.

JerryJS8 said:

Sounds like the clip or pin holding the actuator to the wastegate fell off, leaving the wastegate to flap in the wind.

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Clip was on the WG shaft when I removed the actuator.

Removed the actuator, applied lung pressure to it (I see human lungs produce about 3 psi), the rod doesn't move. My football pump is dead, so couldn't use that to check it. Used my compressor, here's my results:

6psi - rod moves very little
8psi - rod moves less than 1/4" - slow
10psi - rod moves less than 3/8" - slow
12psi - rod moves out fully - med
15psi - rod moves out fully - fast

Actuator holds pressure.

I'm guessing I need to change out the actuator?

Paul

Sounds like it works to me.

Don't replace it.
Did you do a pressurized boost leak test yet?

Onetrillionrpm said:

Did you do a pressurized boost leak test yet?

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Don't have a leak tester.

Check the pressure side turbo hoses, especially the hose at the intake manifold. That one tends to blow out on the underside where it's not visible.

All hoses look good - all seem connected correctly, no cracks or damage that I can see.

Seems easy enough to build a booster tester. All that needs to wait for another day.

malloy1 said:

All hoses look good - all seem connected correctly, no cracks or damage that I can see.

Seems easy enough to build a booster tester. All that needs to wait for another day.

Click to expand...

That's the point. The hole develops on the underside where you can't see it. Feel around the hose for a hole or deterioration of the rubber.

hiperfauto said:

That's the point. The hole develops on the underside where you can't see it. Feel around the hose for a hole or deterioration of the rubber.

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Felt all around the hoses, and still seems OK.

Sounds like the time to replace my old plastic radiator with the new metal radiator that sitting in my shed. I can take the hoses off, check them correctly, and drain the IC of any oil in it.