307 low boost pressure

[gumby6371]

I had the other halfs 307 1.6HDI on Planet last night as its never had any go in it and gives poor MPG's, engine ECU had permanent fault P0029 turbo pressure regulation, turbo pressure measured too low.
I cleared the fault and took it for a test drive and the fault hasn't come back (yet), it revs passed 3000 (eventually) so no limp mode but still isn't boosting like it should, actuator moves freely enough so I don't think the VNT is carboned up and you can hear the turbo spooling. DPF is gone and mapped out so it's not evhaust back pressure and the intercooler pipes appear to be in good condition.
I've always used low saps C2 oil when servicing but it is due an oil change any time now.

Any thoughts?

[Doggy]

Leaky boost pipes?
Leaky EGR?
Dodgy MAP sensor or leaky sensor pipe?
Blocked air filter?

....get another DW12.

[gumby6371]

Thanks Eric,

EGR is blanked and mapped out, had the air filter out a couple of weeks ago and it looks clean and pipe work appears ok on quick inspection.
No idea where the MAP sensor is on these so I'll have to trawl the docs.

I did notice the brakes aren't as sharp as when I drove it before, I'm wondering if I have another vac leak hunt on my hands???

[OllieNZ]

Iirc the map sensor is on the air doser/intercooler bypass assy it has 2 sensors on it and I'm pretty sure one is temp and the other is map.

[gumby6371]

Thanks for that

I believe the actuator is similar to the 2.2 and should apply vaccuum on start up to move the turbo actuator so first off I'll check it moves while my lovely assistant starts and stops the engine. A bit tricky to do that on your own!
Then I'll start looking at sensors, unfortunately planet never plays ball when I try and run actuator tests. Should it be engine on or off to run them?