A couple weeks ago, the fuel line (last one back on the injector pump)started to leak. It took 5 days to get the part and an appointment at an indy and I had to use the car a couple of times while it was still leaking. What started as a 3 second delay after turning off the engine eventually grew to 20 seconds and then no shut down at all. I had to shut it off using the lever in the engine bay. I took it to the shop where they changed the injector line. They also took it to a place and power washed the engine to get as much fuel as possible off the engine. It would still not shut off with the key and the tech said that he saw air in the primary fuel filter and that could be the cause of the problem. He said to just drive it to rid the line of air and that might solve the shut down problem. No joy. In fact, driving away, I experienced pretty harsh shifts both up and down. Since engine shut down and transmission shifts are functions of the vacuum system, this must be the root of both issues.

Does anyone have any ideas to how to go about resolving these problems?

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87 300D 265Kmi
Factory rebuilt crate 603.96x engine at 200K

Okay, well obviously that shop doesn't know what they're talking about... The shutoff and shifts are indeed dependent on vacuum. Likely what happened is that they jostled the vacuum lines and one came loose. During the pressure wash would be my guess. You'll just have to check them all and see if one's pulled out or possibly broken or cracked.

Had the same thing happen. No big deal to plug the line back in or replace it.

-Rog

I did not buy the air in fuel line theory. Then the question becomes how did the fuel leak spray cause the engine shutoff problem even before the power wash?

Like almost shops, this one does not have very deep experience with these older diesels. I would have changed the injector line myself but chickened out when I learned that they are not pre-bent to the specific shape.

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87 300D 265Kmi
Factory rebuilt crate 603.96x engine at 200K

Where did you find the vacuum line disconnected?

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87 300D 265Kmi
Factory rebuilt crate 603.96x engine at 200K

On mine it was at the yellow check valve right by the brake booster, but obviously it could be any of them. That's the general area though where they all branch out to go through the firewall and all that.

-Rog

Try following the line from the vacuum pump to the master cylinder. I broke off a tee that was just before (around 6") from the MC. This was just brittle plastic that snapped while changing glow plugs and valve adjust.

this same shop changed the glow plugs a couple weeks before this started. Now I wonder if the leaking fuel line from the injection pump was not related to the glow plug change out.

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87 300D 265Kmi
Factory rebuilt crate 603.96x engine at 200K

Maybe they swapped the vacuum hoses from the fuel shut off and the green transmission vacuum dashpot

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With god all things are possible -Mark 10:27

Definitely don't just go swapping vacuum lines around. Odds are 10:1 that it's a leak, they're actually pretty hard to mix up, owing to the different lengths and the way they're naturally bent and formed in a certain way after all these years.

-Rog

After 21 years of life my vacuum hoses are just as plyable if not more felexible than new, length? Is to close to call short.
A leak would not disable a full shutoff

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With god all things are possible -Mark 10:27

I guess we'll just see what the OP says the fix turns out to be.

-Rog

Indeed, but it was only a geuss.

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With god all things are possible -Mark 10:27

For information on your car's vacuum system, check here:
http://www.peachparts.com/shopforum/general-information/248948-mercedes-service-manual-source-cd-dvd-paper.html

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Sam

84 300SD 350K+ miles ( Blue Belle )

I am wondering if it could be the diesel shutoff valve. My SD would only shut off with the shutoff lever under the hood. Replaced the shutoff valve just below the VAV and it solved the problem.

Cannot figure out how to copy the link but it is shown in post #13 of my thread named "1981 300SD will not shut off..."

Maybe it is just a coincedence that it went bad at the same time other problems appeared.

the brown lines that goes through firewall to the ignition switch, and then back out through firewall to the ignition pump are the ones that are probably loose/leaking or disconnected somewhere. might find the problem along the brown lines somewhere in the engine compartment, or under the dash on the ignition switch. could be a much larger vacuum leak somewhere else - you mention harsh shifts. Are they harsher on the down shifts - especially the final one? Do your power locks function?

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Andrew
Montclair, NJ
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1982 300D Turbo
120k
Petrol Blue Green