Well, this afternoon I was driving across I-80, west of Lincoln, NE when my 300D started making a load mechanical noise, and bellowing black smoke. I took a look, and the vacuum pump had exploded (big hole in the casing). I pulled out the loose parts, put some duct tape over the hole in the pump, and limped to the next exit. Now I'm in a motel in the middle of NE. My wife is coming to rescue me, so I'll get home tomorrow. I need to decide what to do with the car. I either need to have it towed about 500 miles to home, or my local indy, or I need to find someone near Lincoln, NE to fix it. AFAIK, it's just the vacuum pump, the engine seems to run normally, except it's putting out a good amount of black smoke.

Will just the lose of vacuum cause a 617 turbo to run very rich, or did I break something else too?

The engine starts and idles normally (except for the noise the remains of the vacuum pump is making). It seems to have normal power, but I didn't try to run it above about 1500-2000 rpm. Hopefully, it's just a matter of bolting on a new vacuum pump, but we'll see.

well, go to the auto parts
store and buy some vacuum caps...a
cap off the transmission hose....and just drive it home..

it should just change all the gears quickly....often times
mine smokes becasue the tranny is slipping.... becasue of the
vac....

the only thing it should affect is the tranny,
the off switch, and maybe the alda... that could be
where the smoke is coming from...

Don't forget the power brakes!!!!

__________________
Adam Lumsden
(83) 300D
Vice-President of the MBCA International Stars Section

yep power brakes...

but i think they will still work... you just have to push hard on them..

i think

well, i would be headed to a junk yard...

leave it parked at the hotel and go join aaa...
then have them tow it ...

Somehow I don't think AAA would tow it 500 miles for free. I expect it will be Monday before I make any real progress. The people at the hotel don't mind if it sits here for a little while, and I'm leaving them my spare key so I should be able to arrange a tow over the phone without having to drive all the way back here. If I can find a local MB indy or dealer, I'll probably just have it towed there. Even at dealer rates, that may be cheaper than having it towed home.

Well, I can't really drive it anyplace right now. The vacuum pump basically exploded and has a about 1/4 of the casing missing. The remaining parts are banging around pretty good (even at idle) and it's spraying out a fair amount of oil all over the front of the engine. Hopefully the black smoke is just due to a lack of vacuum to the ALDA/IP, not something more serious. I don't believe the tranny is slipping, just shifting hard due to lack of vacuum. I'm afraid that the pump could lock up and take out the timing chain, etc. At his point, it needs to be towed.

There is no vacuum to the ALDA. The vacuum to the "IP" is actually to the vacuum valve for the transmission, which just happens to be mounted on the IP, but has no affect on the IP itself.

The only impact that I can see on engine operation (due to lack of vacuum) is that the EGR valve won't work, if it still worked in the first place.

Thanks for the info everyone. I'm back home in CO, but the car is still in NE. I took a quick look at it this morning, and decided I need to get it back to my indy in CO. I will either have it towed home, or go back and get it with a trailer.

I still don't understand why it's smoking (heavy black stuff). As soon as I heard the vacuum pump go, I saw a large cloud of black smoke. Other than that, the engine seems to be intact. It idles and runs without any unusual mechanical noises (except the broken vacuum pump), idles at the same rpm, starts immediately (hot or cold). But, it's putting out lots of black smoke under all conditions. I'm afraid to drive it anyplace until I understand what's going on. Is it possible that the vacuum pump caused the timing chain to jump, affecting the valve timing and/or IP timing? I can't imagine what else it could be. I guess I'll just get it back to my indy and let him sort it out.

Could you describe the visible damage to the vacuum pump in more detail?

vac pump has no effect on engine performance it's only a vac supply for trans shifting locks egr and all that crap. If you have black smoke coming out the tail pipe it's for another reason.
That pump runs off the gear that drives the inj pump. That gear houses the advance mechanism for the injection pump, maybe you have some debris jammed in the advance portion making it run slow and smokey.
Colorado Auto Wrecking usually has a good selection of benzes and you can usually walk out of there with a bunch of parts they can't recognise for $10.

It's too late now, but for future reference, Amtrak runs to Denver just south of I-80 with 3 or 4 stops across Nebraska. They only run once a day, but can get you back to Denver pretty inexpensively. Don't think they'll allow the Benz as luggage though.

__________________
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

I was just thinking about that. It may be cheaper to rent a flatbed one-way if I also have to rent a truck (long story). I will price the Amtrak to avoid having to take an extra car.

Last time I checked, renting a U-Haul truck/trailer by the day was waaay cheaper than a one way rental.

__________________
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 agree with kerry. the one way option is very pricey.

uhaul has an excellent car trailer. maybe you can borrow a tow vehicle. i wouldnt use a tow dolly on a bet. nothing but bad experiences with them.

i also agree to avoid running it. if a part drops down into the timing chain it will break the chain and the pistons will hit the valves, etc etc etc.$$$$$$$$

so i would prob take a comealong and winch it onto the trailer.

tom w

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.