Mercedes-Benz W140 turbodiesel boost pressure and vacuum hoses
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Why does the W140 turbodiesel boost pressure not rise and the car lacks pull?
The turbo wastegate works on vacuum. If the vacuum hose has come off or the turbo otherwise does not get vacuum, boost pressure does not rise, the revs climb slowly and power is missing. The fault can appear, for example, after servicing.
What should be checked on a W140 turbodiesel when boost pressure is missing?
Check the turbo vacuum hoses, the wastegate hose and the vacuum regulator, and the hose running from the intake manifold to the feed pump. When vacuum returns, the pull returns. The wastegate hoses should not otherwise be touched; blocking them does not add power.
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