TD42 Losing boost pressure

[mudski]

You will be taking out the intercooler. straight off the actuator will show you the boost output at the turbo

Ahh ok.

I don't have a boost port pre intercooler though. Or am I missing something?

[MudRunnerTD]

Ahh ok.

I don't have a boost port pre intercooler though. Or am I missing something?

yeah the hose nipple at the actuator is pre intercooler.

[mudski]

yeah the hose nipple at the actuator is pre intercooler.

Hmm.
Right. This is something I've never played with so its all new to me. So all Im doing is removing the boost hose from the controller to actuator? Go for a spin and see what I get in boost pressure?

[jff45]

Hmm.
Right. This is something I've never played with so its all new to me. So all Im doing is removing the boost hose from the controller to actuator? Go for a spin and see what I get in boost pressure?

Not quite. What I’m suggesting is to read the boost that’s coming directly from the turbo to eliminate any issue with the wastegate.

On the turbo compressor housing there will be a barb where the boost pressure is sent to the entry side of your boost controller. Something like the brass barb on my P4x4:

B2A113E7-C7BC-4F64-9046-0675EFA1C7A1.jpeg

You need to take the hose from your IC, or wherever the boost gauge gets its reading, and connect it directly to that barb so the gauge reads the boost the turbo is making. You’ll almost certainly have to lengthen it to reach.
That should completely isolate your boost controller and the boost will have no effect on the actuator.

[mudski]

Not quite. What I’m suggesting is to read the boost that’s coming directly from the turbo to eliminate any issue with the wastegate.

On the turbo compressor housing there will be a barb where the boost pressure is sent to the entry side of your boost controller. Something like the brass barb on my P4x4:

B2A113E7-C7BC-4F64-9046-0675EFA1C7A1.jpeg

You need to take the hose from your IC, or wherever the boost gauge gets its reading, and connect it directly to that barb so the gauge reads the boost the turbo is making. You’ll almost certainly have to lengthen it to reach.
That should completely isolate your boost controller and the boost will have no effect on the actuator.

My Turbo doesn't have that barb as per pic.

[jff45]

Ok, in fact, if you have a boost leak in the system then it will be down on boost anyway.

[mudski]

I spoke with a customer yesterday who's a TD nut and he told me to use my air compressor and run 5psi and then in 5 psi increments directly into the actuator to see if it moves and when, as he said its likely either the actuator is kaput or even the wastegate springs have broken. So I'll attempt this over the weekend.

[jff45]

That's why I was suggesting testing boost directly with the wastegate firmly shut. If the spring is broken inside the actuator, although I've never heard of that on any forum, you should be able to just feel the loose actuator rod with your fingers.

[mudski]

That's why I was suggesting testing boost directly with the wastegate firmly shut. If the spring is broken inside the actuator, although I've never heard of that on any forum, you should be able to just feel the loose actuator rod with your fingers.

Ahh ok. I wasn't sure what you were actually trying to find with this. Makes sense now. Sorta. i've never had to dabble in this part of the TD's so its all new to me.

[mudski]

Update. So I clamped the boost line shut to the actuator. Took it for a spin and wow! Full boost and she screamed!
Just got to figure out what this means. What part has failed to cause this. The controller is merely a needle valve which restricts air flow. It works. I can wind it right in and it shuts off flow. So I can’t see this being the cause, but who knows.

Atleast I’ve made some progress.


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