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What Vacuum Should Turbo Actuator Rod Start Moving

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#1 munster_skye

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Posted 02 June 2015 - 01:40 PM

  Trying to get to the bottom of turbo underboost problem.

  With a vaccum pump ( with guage) the actuator starts moving at 10" Hg.  Is this about right?

2008 1.6Tdci

#2 rob18

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Posted 02 June 2015 - 04:38 PM

Just done some searching around to try and give you some help. 10 HG = 0.33863886666699994 bar = 4.91155 PSI.

In terms of finding what pressure the 1.6 tdci turbo goes up to it's pretty hard to find, however the same turbo is fitted in a few cars and one site said it should be running around 0.2 bar @ 2500rpm and 0.6 bar @ 4000rpm.

Found on another site when testing a Porsche 911 turbo the actuator opens at around 0.5 bar.

Judging by that, you're actuator starting to open at 0.33 bar sounds about right (however you could always try a new spring to see if yours has softened and hence underboost)

Other than that there could be various problems, splits in turbo pipe, blocked egr valve etc.

Could be worth getting the turbo system pressure/smoke tested to see if there's any leaks, there's a video of an American guy who took a draw on a cigar and blew the smoke into a turbo pipe, this aloud him to see the smoke coming out from the split in his pipe to quickly solve the problem, might be of some help?

#3 munster_skye

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Posted 02 June 2015 - 06:40 PM

Thank you for info... i am in the process of checking all pipes etc.  I was manually moving the actuator with a vacuum guage/pump to check its movement (range/stickiness) and thought the 10" hg (0.33bar - thank u) was too high.

I vaguely remember doing something similiar on a Ford Galaxy 03 1.9tdi and it started moving at 5" hg but it was a while ago and i'm not expecting all cars to be the same)

The spring you mention about replacing - is that easy to do?