newbie post-search vacuum question - PeachParts Mercedes-Benz Forum

Terry240d · #1 04-11-2006, 01:26 AM

Hello-

for my 1982 240d manual transmission:

I accidentally pulled off a small brown vacuum line while changing the oil today- the one going to the shut-off valve. I thought I replaced it correctly, but now I can't shut the engine off without letting the clutch go while in gear.

I did notice oil in the vacuum line, and a few drops of oil where the lines meet the ignition switch. A search tells me that seeing oil means I need to replace the vacuum fuel shutoff valve, and I'll do that, but shouldn't the car shut off now that I've replaced the line? It never gave me a problem before today. Perhaps I also pulled the line off at the ignition? I felt around and it seemed like they were connected, but with the oil there, maybe the rubber 'connectors' are cracked? I can't find a reference to those on fastlane or **************.

I'm probably missing something obvious, but thanks for any assistance!

barry123400 · #2 04-11-2006, 01:55 AM

Rather than shutting down using the clutch. Until you solve the problem there is a lever on the injection pump that says off. Just press it. I also understand your concern that once the tube was put back on function should have resumed. Perhaps the tube cracked allowing vaccum to cease. Guess the first thing I would try to establish is if there were vaccum at the end of the vaccum line when engine was first turned off. Basically you want to check the shutoff with a mityvac type of tester. It pulls and holds a vaccum plus has a gauge. If shutoff is good it will stop the engine when you pump up your mityvac or equivelent.If a guy is going to continue to own one of these cars he probably should invest in one. I picked up a cheap chinese all metal version awhile ago. For my limited use it will probably last. For a working mechanic it is probably another story.

Terry240d · #3 04-11-2006, 02:13 AM

Unfortunately, the car is not shutting off with that 'stop' lever either.
The idle slows off lots, but the car does not shut off.

will do re. the Mityvac.

meltedpanda · #4 04-12-2006, 10:17 AM

sounds like the shutoff, oil is not good as you indicated, I think the line removal may have been the final straw for the "closed system"
Why the shut off does not work is a bit of a mystery may or may not be related
Another way to check the shut off is to apply vacuum to see if you can shut off engine. You can do this a number of ways, I use an old style basketball pump and an vacuum line,I create vacuum on the pull back stroke.
Also research R/R of pull off valve, replaced incorrectly may result in runaway engine and a major mess and dangerous situation.
I usually just loosen my fuel line just in case.
Good luck

Terry240d · #5 04-12-2006, 10:20 AM

"...at the back of the fuel pump facing the firewall"...

must've seen this three times in the searched threads...I finally digested those words and looked harder. I had re-attached the brown line to the wrong spot- found the correct spot and car now stops with the key. Of course, I now need to find out why there's an (apparently) obvious vacuum connection point on top of my fuel pump that's unused. Also, I now know that if there's oil in the line, the fuel shutoff valve needs to be replaced.

thanks Barry, and all who have written on this before! It took me a while,

but your words paid off...

Terry240d · #6 04-12-2006, 10:22 AM

Thanks-
I was writing exactly the same time as you.

I'll read up on the issue you mentioned- I'd rather not have a runaway!!
thanks
TR

george d · #7 04-12-2006, 10:37 AM

I seem to recall that my manual shut off would not work because the fast idle cable was too tight. It wasn't so tight that the idle wasn't normal, but it was too tight to allow the manual shut off switch to be pushed far enough. The idle would slow way down, but keep running as you described. Seems that maybe I had to buy a new nylon bushing for the cable as well. Its been several years ago.

You might give that a try.
Good luck!

Terry240d · #8 04-12-2006, 10:38 AM

Diesel Giant · #9 04-12-2006, 06:43 PM

The linkage that is attached to the "stop " arm is not adjusted right. Just adjust that arm only to get the stop lever to work correctly.

driad_98 · #10 04-19-2006, 05:08 PM

I'm having a shutoff and locks problem... I've tracked it down, I think to a leak in the vacuum circuit that begins with a green/yellow vac line in the engine compartment, right near the firewall. Does anyone know what the green/yellow line leads to?
thanks!

Diesel Giant · #11 04-19-2006, 08:15 PM

Test the shutoff valve for proper operation.

http://dieselgiant.com/repairyourshutoffvalve.htm

driad_98 · #12 04-20-2006, 04:33 AM

Oddly... I diagnosed a defective passenger front lock pod, and also an open circuit on that one green/yellow vacuum line. I think that one had something to do with the AC compressor switch, or someone mentioned something about that... anyway... I fixed the problem by hooking only the brown shutoff feed and the lock and reservoir check valve lines to the vacuum. I left the green line disconnected as well as the whole vacuum modulator thing on the IP... Even with these lines disconnected, I can't tell a difference in the running condition... so, now the locks work, the car runs great and smooth, the heat works and I have no symptoms from leaving those lines disconnected. Bully for me, eh?

Oh, what's the best place to score a new vacuum pod?

Cheers!
Ash