As a new diesel owner, it's the simple things that mystify you. My 300SDL now refuses to stop running when I turn off the key.

I've been trying to decipher the Repair Manual CDROM and figure out what mechanism is supposed to stop the engine, but no luck yet.

Last week I replaced the fuel line feeding directly into the engine (which is when the problem started). The previous one was allowing air into the line. The new fuel line is slightly bigger that the last one, so I assumed that the engine kept running merely because it was getting too much gas. However, I tried a quick fix by tightening a hose clamp to restrict the fuel flow - didn't change a thing. The old girl just chugs along until I get out of the car, pop the hood, and hit the kill switch.

Any wisdom for an aspiring DIY shade-tree mechanic? Will I have to find a smaller fuel line, or does that make a difference? Is it an electrical system that kills the engine?

Andy

87 300SDL 289,000miles

Check your vacuum lines, the cutoff swich is vacuum operated. The white plastic box next to the ALDA on top of the Injection Pump is the cutoff. Make sure those lines are good, and connected properly.

Andy:

Most likely you pulled a vac line off while changing the fuel line.

The brown plastic line is the supply, the brown line with a blue stripe connects to the vac servo on the IP to shut the engine off.

Use the stop lever to kill the engine until you get it fixed.

There is also the possiblity that the servo died, you are about the right milage.

Use a MitiVac hand pump to test -- engine should stop instantly when you apply vac to the servo with the hand pump. If it doesn't, or the vac leaks down, replace servo.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Mine did the same thing the servo wouldn't hold vacuum. They are about $46 for a Bosch metal one. Cheaper plastic ones are less but I hate plastic crap.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200