83 300SD Turbo doesn't shu off

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dobbsc@webtv.net - 26 Oct 2005 13:50 GMT

When the engine is shut off I know it has a delay time to cool down the
turbo . But now it gust keeps running. Where is this part located on the
engine and what is it called. Do you have to replace it or is there
something else to lok for electrical. Thanks for any help Charlie

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Karl - 26 Oct 2005 15:29 GMT

It is 100% vacuum operated.

There is/was NO delay ever built in to cool off the turbo. THAT delay was a sign telling you
something was wrong and you have a small leak in the vacuum system. Now it has a major leak and it
won't shut off the engine.

> When the engine is shut off I know it has a delay time to cool down the
> turbo . But now it gust keeps running. Where is this part located on the
> engine and what is it called. Do you have to replace it or is there
> something else to lok for electrical. Thanks for any help Charlie

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dobbsc@webtv.net - 27 Oct 2005 03:19 GMT

Thanks Karl, I will have to look for the vacuum leak. This is a friends
car, is there alot of vacuum operated things on this car? Is there a
vacuum diagram that someone can help me with? I have an 85 Volvo 240
Turbo that I have restored and vacuum leaks are a major sorce to alot of
problems. Thanks, Charlie

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Karl - 27 Oct 2005 14:51 GMT

On your 126 body, there is only 3 circuits that run off engine-made vacuum: the shut-off system,
the climate control, and the transmission shift quality. When you have a major leak in the climate
control, all the air blows out the defrost......
By the brake booster area, look for rubber Tee with small vacuum lines in it. Each plastic vacuum
line is color coded for the system it affects. Red and green is climate control, brown is engine
shut-off. Plug off the red and green ones on the engine side. In other words, stop the vacuum from
going into the car. Don't unplug a red line or a green line and cap that line, you have to stop the
vacuum coming from the source.
Now you should only have the brown line connected to the Tee. Start the car, then shut it off. Does
it shut off instantly? If yes, your vacuum leak in in the dash. If no, go to the diaphragm on the
rear end of the injection pump and pull off the brown w/stripe line off and feel for vacuum in the
line. Does it have vacuum? If yes, you have a blown shut-off diaphragm. If no, you have a bad vacuum
switch on the steering lock [highly unlikely] or a bad vacuum pump [but if you had a bad pump, you
would have complained of no power brake assist].
Best tool to check everything with is a hand-held vacuum tester like Mighti-Vac etc.

> Thanks Karl, I will have to look for the vacuum leak. This is a friends
> car, is there alot of vacuum operated things on this car? Is there a
> vacuum diagram that someone can help me with? I have an 85 Volvo 240
> Turbo that I have restored and vacuum leaks are a major sorce to alot of
> problems. Thanks, Charlie

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