Boost Leak?

[burlsube]

I noticed in the last few days that I am struggling to get to my usual level of boost. I have the Alisport turbo and my boost was at about 18psi when under full throttle. Now I'm struggling to get to 14psi. I also see the boost needle shaking under some circumstances.

I verified the gauge connections are tight. Intercooler and hoses are new. I changed the airfilter and disconnected it from the snorkel.

Overall driveability is ok but not as responsive as before.

What else can I check?

 

[Napalm00]

Hose from actuator to the turbo
Air filter and intake for blockages
Intake hose for collapsing under boost
Clogged fuel filter

 

[burlsube]

Thanks. For the intake hose collapsing can that be verified by someone reving the engine while just looking at the hose?

 

[rocky]

If the wastegate is partly open all the time, that wont help boost pressure.

 

[Napalm00]

Yup, also what Rocky says is correct.

 

[Red90]

If the wastegate is partly open all the time, that wont help boost pressure.

I assume this is a VNT......

Check that the vane actuator is able to move freely and that it is closing fully.

 

[Red90]

Thanks. For the intake hose collapsing can that be verified by someone reving the engine while just looking at the hose?

No. It happens inside the hose. The outside will look fine.

What engine is this?
What adjustments to the fueling have you done?
Is there smoke at full throttle and full boost?
Do you have an EGT gauge? If so, what is sustained full throttle EGT?

 

[burlsube]

Got it.

It is a 200tdi. I have turned the diaphram about 45 degrees more aggressive. There is a light haze at full throttle and full boost.

When it was boosting to 18psi I could easily get up to 1250-1300 before I would back off.

 

[Red90]

The question is what is it now. If fueling is unchanged and the boost is down, then the smoke will be worse and the EGTs will be higher. If smoke and EGTs went down then there is a fuel supply issue.

 

[burlsube]

OK. I'll start with the fuel filter. The IP is new. I have definitely noticed a lot more smoke when starting up, but I guess I was attributing that mostly to the cold temps.

After the filter, move on to injectors and lift pump?

 

[Napalm00]

Now that I think of it it is a vnt right? The turbo may have excess carbon built up keeping the vanes from fully opening. You can check this by removing the actuator rod and moving the lever back and forth, they should move by finger pressure only with no resistance.

I'd check the filter and the flow from the pump, but don't go nuts pulling the injectors, it's probably not them.

Most likely the issue is related to the turbo or boost lines/actuator/lever

 

[burlsube]

Ok. I'll give that a try.

Just curious, but why would carbon build up so rapidly?

 

[Napalm00]

Poor tune, heavy foot, bad fuel, running undertemp, overly restricted exhaust, leaky injectors, ect ect

You may need to pull the exhaust to see if the vanes are opening and closing if you can't feel it

 

[burlsube]

So two stupid questions -
1)
What are the clips on the turbo actuator called? I havent seen those before and I'd like to remove them with the appropriate tool?

2)Is it worth updating a newer style fuel filter? The one pictured seems to be an older and smaller capacity filter.

 

[Napalm00]

They are double oetiker clamps, you cut them with sharp side cutters to remove... That hose looks almost new tho.


Your filter is the standard defender type and they work fine. You can get a larger element from some suppliers or change out the filter head to a stanadyne fm100. You will need some other small parts for the conversion and new lines as well.


Just by looking at at the age and condition on these components I doubt they are causing your problem. They both look Nearly New

 

[burlsube]

Thanks. I guess that leaves fueling as the area to focus on.

Or maybe the VGT vanes have carbon on them, although that seems unlikely as I have only like 2k miles on the turbo.

 

[Napalm00]

It certainly won't hurt to change the fuel filter!

You can check the vanes by disconnecting the actuator rod and moving the Armature back and forth with your finger. It should move freely with zero resistance

 

[Red90]

Your filter is the standard defender type and they work fine.

That filter is the one used before the TDIs and is NOT AT ALL SUITABLE. It was intended for the indirect injection motors, which have very larger injector openings.

Hopefully you have not already plugged the injectors.

Immediately change to the correct TDI filter or use an aftermarket one Stanadyne FM-100 or Racor.

Then pull the injectors and get them spray tested.

 

[Napalm00]

Forgot, the filter element is available from RovahFarm:

http://www.rovahfarm.com/defenderfuelsystem.htm

It is a mahle kx23 you can get aftermarket online and some auto parts stores

 

[Red90]

Can you take a picture back further on the fuel filter lines. Looks like it is hooked up like the old engines, with the return line going to the filter. This is a really bad arrangement as air can't get out of the system.