Original post Vacuum Question (easy one) Ref: 79 240D does not shut off with key, and locking system is inop. The locking system and engine shut off happened at the same time. Then one day the engine shut off with the key, but wouldn't start back up. I went out the next day and it started right up. The next time I drove it I had to shut it down manually and it wouldn't start again. Later that day it started up.??

So, my Mighty Vac finally arrived and I started the troubleshooting process. The first step left me more confused than I was to start with...
I went out and it wouldn't start, so, I hooked the MV directly to the fuel valve and pumped it up, the car started (though it wouldn't hold vacuum at the valve, it bled down, which would lead me to think this was the problem with the system). I thought vacuum on the pump shut the car off? Anyway, there is a brown line running from the vacuum source to the ignition switch, there is a brown w/blue stripe running from the ignition switch back to the fuel valve. When I plugged the line at the fuel valve and applied vacuum to the brown line at the source with the ignition off it held. With the ignition on it didn't?
If I take the brown lines out of the system (the fuel valve), the whole system will hold vacuum, but the locking system will still not work.
I have looked at the diagram for the 240d, but it is not for the 79, which appears to be a much simpler system.

Can someone tell me: Does the fuel valve require vacuum to shut the fuel off, or, to allow fuel to flow, and what could cause it to be intermittent.
Here is a link to photos of the IP. http://www.flickr.com/photos/11103112@N03/sets/72157601329107041/
Ignore the finger.
Thanks in advance for any feedback.

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Resurrected Nov 2010 - 79 240(SD) with 83 617 engine and 4 speed manual, 2.88 rear and 2.5" straight pipe unknown mileage (Salmon)
83 240D parting out
96 Dodge Cummins 5 sp 4X4 long bed - 310k

http://flickr.com/photos/11103112@N03/

You're asking questions over my head, but I recently replaced my Shut Off Valve. If you need help doing that, even though my model is different, you can call me. Doing it over posts will take forever.

jeff 404-351-3734 1991 300d

Thanks Jeff.
I think that may be what I need. I just went out and started the car and hooked the MV directly to the valve and pumped like hell and the engine shut down. I re-started it and tried again, it wouldn't shut down no matter how hard and fast I pumped. It's gotta be the valve? Must'a been a fluke this morning when I startted it by pumping.

How difficult was yours to replace, do you have to pull the whole pump?

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Resurrected Nov 2010 - 79 240(SD) with 83 617 engine and 4 speed manual, 2.88 rear and 2.5" straight pipe unknown mileage (Salmon)
83 240D parting out
96 Dodge Cummins 5 sp 4X4 long bed - 310k

http://flickr.com/photos/11103112@N03/

Vacuum to the shut off valve shuts down the engine. Vacuum should bleed off with the ignition switched off so it sounds as if your ignition switch is fine and the shut off valve bad. Also sounds like you may have vacuum leaks in the door lock system.
You can remove the shut off valve and replace it without removing the injection pump. Search and read the threads on the topic. There is a possibility that an improper installation will cause the engine to run away upon start up so be prepared to stop the engine by choking it.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Yeah, I've read about the run away diesel, I'll certainly be prepared for that.

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Resurrected Nov 2010 - 79 240(SD) with 83 617 engine and 4 speed manual, 2.88 rear and 2.5" straight pipe unknown mileage (Salmon)
83 240D parting out
96 Dodge Cummins 5 sp 4X4 long bed - 310k

http://flickr.com/photos/11103112@N03/

Ditto to what Kerry said. I replaced mine a while back and was quite nervous, but it wasn't too hard. Has worked perfectly since. I think Diesel Giant has a pictoral of how to do this.

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John Schroader
bio burnin' 83 300D, '83 300 SD, '79 240D
"I've never met a man who was good at making excuses who was good at anything else" Ben Franklin
"You cannot permanently help a man by doing for him what he could and should do for himself" Abraham Lincoln

Yeah, I'm going to replace it and see what happens. Thanks for the feedback, I'll check Diesel Giant for the diy.

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Resurrected Nov 2010 - 79 240(SD) with 83 617 engine and 4 speed manual, 2.88 rear and 2.5" straight pipe unknown mileage (Salmon)
83 240D parting out
96 Dodge Cummins 5 sp 4X4 long bed - 310k

http://flickr.com/photos/11103112@N03/

Just did this in the SD. Does the manual shut off lever work? Mine did, install like you remove, the vac nipple in the same orientation. I used a gasket adhesive to hold the sandwich together while I bolted it back in.

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83 SD

84 CD