Greetings,

I recently had to cruise from Memphis to Nashville (on the way to Cincinnati) with a sever fuel leak that naturally caused a misfire. The additional shaking brought about by the misfire has wreaked some moderate havoc on my vacuum lines, now it will not turn off with the key and I was hoping someone might have an example.

The previous owner did some fiddling with vacuum lines that I always figured to be bypassing some sort of emissions system, but never looked into it. with regards to they key no longer cutting the engine, I have reconnected the brown/blue line and it appears to be fully intact. It appears that the p/o's fiddling focused around the two black units attached to the secondary firewall. I have found some handy diagrams depicting the vacuum system however they only depict one unit described as a "engine overload protection switchover valve". As far as I can tell, this has been completely bypassed (as seen in photo one, the line coming straight off the intake manifold). Photo two is really where my question lies. Where are these lines supposed to go? Maybe I'm just too dumb to read the diagram correctly but I only see the one unit.

If anyone is able to take a reference photo of the firewall mounted units and where the lines run on their 603 SDL that'd be fantastic! Thanks all!


-Image One: engine overload protection switchover valve bypass line + intact brown vacuum shut off unit line
-Image Two: the two black units, not sure of one's function (the other is bypassed). don't mind the current plumbing, I was just test fitting. (ps do you like the manual heater control valve? Apparently this was a part of running veggie oil, once again the p/o.)
-Image Three: Diagram I followed

Attached Thumbnails

     

The ignition cutoff is blissfully simple on the SDL's. There's a nipple off the check valve at the brake booster (61b on the drawing). It goes to the key switch (Brown Line b in the drawing). The key switch (Brown/Blue Line b in the drawing) goes to the vacuum pod (6 in the drawing) on the top of the injection pump. That's it. If it's connected any other way it's wrong and should be corrected. The idea was to improve on the earlier cars that failed to shut off if any vacuum issues were present. On these cars, if there are vacuum problems with any other part of the car, the engine should still shut off if your brake booster is vacuumed down.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

I was starting to get concerned about having damaged or dislodged the vacuum line under the dash, however with a little more investigating, the rubber elbow was not forming a tight seal over the nipple. Trimmed a bit of the tired end off, and it formed a tight seal. After about a week it still shuts off with the key.

Thanks!