that runs from the back of the IP to the intake manifold. The vacuum in this line controls the amount of fuel in relation to throttle position and the vacuum supplied here performs a balancing act with the springs that push on the diaphragm inside the IP. At full throttle there is no vacuum and the governor spring pushes the diaphragm which in turn is attached to the rack and pushes it to full fuel.
If this line gets disconnected or gets a leak in it you will have a runaway with lots of smoke as the rack will go full forward and give you full fuel.

Ths shutoff should still work though... If this line were to break though I have no idea how the engine would get oil to burn from this connection...

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'99 S420 - Mommies
'72 280SE 4.5 - looking to breathe life into it
'84 300SD Grey - Sold
'85 300SD Silver - Sold
'78 Ski Nautique

Thanks for all the great ideas. When I know something I'll be sure to post the results.

Kind Regards.
Drew

William: profession. I think they just want to get me killed before I get a chance to retire!

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daBenz - 1970 220D

It was a ruptured vacuum pump diaphragm. The PO had it rebuilt last year, and the best we can figure is that it was assembled incorrectly. There were some broken washers in there as well.

Thanks for all the advice.
Drew

Now that sounds like a job I could get into. What do you do to them?

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One more Radar Lover gone...
1982 VW Caddy diesel 406K 1.9L AAZ
1994 E320 195K

drewleroy, good job. Sounds like the max fuel delivery screw was adjusted for too much power. Located under the diaphragm, it needs to hit before before the diaphragm spring. Some adjust it for "more power" but perhaps that's the reason for your broken washers.

wolf_walker, I'm going to sample mercury from power plants. Mercury is next on the list of stuff to be regulated by EPA, and the plants want to know what they're sending out before the rules hit the street. It's not much (in the order of 10/millionths of a gram (sic) per cubic meter), but then again it does add up over time. One has to be pretty exacting to even measure at that level. The toys I use cost in the six figures.

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daBenz - 1970 220D