Turbo boost trouble

[E_T_V]

In the process of getting my TD campervan back on the road, I fitted a boost gauge as I suspected there was something amiss somewhere as my performance wasn't very good. Anyway I was proved right and the boost pressure seems far too low. I was getting about 0.5 bar at max speed at full throttle and about 0.25 under heavy acceleration at normal rpm's. (Standard boost in the book figure is a tad under 1 bar). Obviously this isn't right so I've been gradually shortening the actuator arm bit by bit, (I'm nowt at 4 turns!).

Anyway I've got to the point now where at max rpm and full throttle I'm just hitting 1 bar but at more normal engine speeds I can't get it above 0.5 bar. Now obviously I don't want to turn the actuator further if it is going to increase the boost pressure at the top end as that may make my engine re-arrange itself, but I feel that there still isn't enough boost at mid range rpm's. Has anyone out there got some figures that I should be aiming for, (before I then set up my fueling). The reason I think things aren't right is there is no turbo "whoosh" as it were where you can feel the turbo kick in. You can feel it on other TD's I've been in but not on mine.

Any ideas or advice anyone?

[weasel2400]

Im sure you would have checked this but is the oil level/condition ok and the turbo pickup pipes ok - the turbo isent happy without plenty of clen oil, mine takes quite a while too kick in, authogh you do feel it when it does.

[E_T_V]

Oh yes it is working ok, spins freely and has a decent oil supply etc, it is just the boost pressure isn't obtained until you are thrashing the nuts off of it. Most of the time in normal driving I'm only getting half the rated boost even when I put my foot down on the motorway.

[weasel2400]

Verry strange, my only other thought would be a vacum leak from the sensor & pipes on top of the ingition relay, best of luck tracing problem at any rate.

[Nikamota]

Another suggestion,if you havent checked allready.make sure the wastegate isnt stuck open ie that it hasnt detached from its operating rod from the vacum.
Also check the turbo output pipes to the inlet manifold are not split anywhere.

Make also sure that the vehicle is actually receiving full throttle.

And finally check that the air cleaner isnt choked.

These are not specific to Maestro/Montego but turbos in general and can cause these sorts of symptoms.

Hope this helps along with the other suggestions.

Good Luck!

[E_T_V]

Cheers for the advice. Unfortunatly I've already eliminated almost all of those possible causes. I'm hoping my actuator is dead rather than my wastegate not seating correctly, as I've got a new one to fit. The only other option I have considered is to add a boost control valve which will prevent any boost pressure reaching the wastegate until it hits a specified pressure in order to prevent any possibility of it opening early.

[Nikamota]

Your last suggestion is a very good idea,even just to test the wastegates operation,seating.

Keep us informed as to the result. :thumbup: