My 300SD wont SHUT OFF ?? - Page 2 - PeachParts Mercedes-Benz Forum

pantherpaw · #16 01-10-2008, 10:33 AM

Quote:

Originally Posted by vstech

um, actually, if the 50-100.00 fix would work, then the hose rig would not... the hose rig assumes there is a leak, and bypassing the vac circuit shuts off the car.

Thats a damn good point, I was thinking if the vacuum wasn't strong enough due to a sticking valve that my bypass rig would provide more vacuum than its getting with a leak...but hey, I'm new to all this so I'm listening to you guys...This site is a real life saver...

cdplayer · #17 01-10-2008, 12:40 PM

Quote:

Originally Posted by pantherpaw

1983 300SD - 5 Cylinder Diesel - What device turns off the engine, and how can I check it. I'm guessing its a vacuum operated fuel valve of some sort...Anybody know how to solve this problem...?

Hello David. Good to talk to you again. I've read all the responses here to your problem of engine shut down. I think your problem is in your ignition switch. I have sold my shop manuals on this vehicle, so I do not have schmatics to review.
If you pull out your instrument cluster you will find two vacuum lines attached to the lock cylinder.
I replaced such a cylinder years ago on my first Mercedes. It seemed then that the valve inside the cylinder activated by the position of the key failed. Cost me three dollars at Pic N Pull. Good luck!!

kerry · #18 01-10-2008, 01:55 PM

The only things we know at this point are the following:
There's a vacuum problem.
The problem is not in the door locks because it's an SD with a separate vacuum system for those.

Beyond this knowledge we can suspect some other things:
Probably not the brake booster or the vacuum pump because these would cause changes in brake pedal pressure that probably would have been noted in the original post.

I don't think there's any evidence so far that hints at the exact cause of the problem.

LUVMBDiesels · #19 01-10-2008, 03:02 PM

Quote:

Originally Posted by cdplayer

Hello David. Good to talk to you again. I've read all the responses here to your problem of engine shut down. I think your problem is in your ignition switch. I have sold my shop manuals on this vehicle, so I do not have schmatics to review.
If you pull out your instrument cluster you will find two vacuum lines attached to the lock cylinder.
I replaced such a cylinder years ago on my first Mercedes. It seemed then that the valve inside the cylinder activated by the position of the key failed. Cost me three dollars at Pic N Pull. Good luck!!

Mine had the leak in the valve off the ignition switch. But the way mine leaked, vacuum was going into the shut off valve all the time shutting down the car. Replacing it is a pain even with the instrument cluster out as it is hard to reach with big fat fingers.

You know that there is a big red STOP lever in the fuel linkage, right? You can always pop the hood and push the lever to stop the engine.
I did that for a couple weeks until I broke down and bought the part for $24.

I tried running a piece of vacuum tube from the SOV into the car, but my wife refused to suck off the car

spark3542 · #20 01-10-2008, 03:46 PM

Quote:

Originally Posted by kerry

If you don't have a Mity Vac, put a long piece of vacuum hose on the valve in place of the brown vacuum line and suck on it. If it shuts the engine down, the valve is ok and the leak is elsewhere. This is the most common situation.
Shut off valve won't look quite like that on the car. It's hard to see, down between the back of the injection pump and the front of the oil filter housing.

Depending on the amount of redneck in your genes, you could simply run the vacuum hose out of the engine compartment at the cowling, leaving about a foor or so protruding. You can then shut off the engine without opening the hood by simply giving two quick sucks on the line.
If your redneck heritage is less, you could take the time to thread the vacuum hose thru the firewall leaving it accessible to suck in the passenger compartment.
If you have a long dignified family line, you'll have your footman seek out the system's vacuum leak and repair it.

This post had me laughing out loud at my computer. It reminded me of the crude old joke about "my GF" is able to "suck the chrome off a trailer hitch" or "suck-start a harley"...now we can add "suck-stop a Mercedes"

jbach36 · #21 01-10-2008, 09:40 PM

I just did that SOV on my 1991 300d. The part itself was $29? It wasn't that much. Getting into the area on my car was a *****. Seems to me Prayton has a post on how to do it. I tried to find a better way to fix it, but no such luck.

I can tell you how to do it on mine, it might help you....

If you don't have a MityVac, you can go to AutoZone, they have a free rental program. Buy it, use it, return it, get your money back. I did it even easier, just borrowed it and checked it while there, then gave it back. Just disconnect the hose leading up to it. Put the MityVac on. If you squeeze the handle and the SOV lever goes down and stays down for 10 seconds or so, the SOV is fine. But with mine, it went down for a second or two, and not the whole way either, so, it was time to replace.

The rest of the repair is pretty much straightforward. Almost wysiwyg. In my case, I had to disconnect the cruise control lever, the Alda, and a few other parts to get to it. Once that was done, put the part in carefully (read Prayton's post), and be prepared for a runaway diesel. That means, once you start your car, it's going to run full throttle and basically blow up in very short order. It probably won't happen, but be ready. To be ready, you have to block any air from coming into the crossover tubes. I had a stiff piece of cardboard to put inbetween where 2 of the tubes come together.

Good luck, and be safe. It's not that bad of a job, a bit trying, but you'll be a better man, or your wife a better woman, after doing the job. Send her on a mission to fix it for you.

Jeff 1991 300d, 115k

pantherpaw · #22 01-11-2008, 08:38 AM

Quote:

Originally Posted by LUVMBDiesels

Mine had the leak in the valve off the ignition switch. But the way mine leaked, vacuum was going into the shut off valve all the time shutting down the car. Replacing it is a pain even with the instrument cluster out as it is hard to reach with big fat fingers.

You know that there is a big red STOP lever in the fuel linkage, right? You can always pop the hood and push the lever to stop the engine.
I did that for a couple weeks until I broke down and bought the part for $24.

I tried running a piece of vacuum tube from the SOV into the car, but my wife refused to suck off the car

Actually, I am trying to get the car ready for her to drive...and she wont have it because it wont shut off...and although she is able, she is not willing to "suck off the mercedes" I have to get this fixed or be faced with buying another car...YIKES...

pantherpaw · #23 01-11-2008, 08:43 AM

Quote:

Originally Posted by LUVMBDiesels

Mine had the leak in the valve off the ignition switch. But the way mine leaked, vacuum was going into the shut off valve all the time shutting down the car. Replacing it is a pain even with the instrument cluster out as it is hard to reach with big fat fingers.

You know that there is a big red STOP lever in the fuel linkage, right? You can always pop the hood and push the lever to stop the engine.
I did that for a couple weeks until I broke down and bought the part for $24.

I tried running a piece of vacuum tube from the SOV into the car, but my wife refused to suck off the car

I know about the red "STOP" button, but she ain't likin the idea of having to pop the hood everytime...she's starting to hint around that she wants my new old 300CE which is a cream puff...which aint happening...she wants to drive the new one and leave me with the old one...Women these days! I didn't even find the SOV when I looked for it...help...

pantherpaw · #24 01-11-2008, 08:46 AM

I'm going to read Prayton's post and get back to this in a little while...it seems that "cdplayer" had some success with the article...in the mean time, any other advice is much appreciated...thanks

pantherpaw · #25 01-11-2008, 09:22 AM

Quote:

Originally Posted by jbach36

I just did that SOV on my 1991 300d. The part itself was $29? It wasn't that much. Getting into the area on my car was a *****. Seems to me Prayton has a post on how to do it. I tried to find a better way to fix it, but no such luck.

I can tell you how to do it on mine, it might help you....

If you don't have a MityVac, you can go to AutoZone, they have a free rental program. Buy it, use it, return it, get your money back. I did it even easier, just borrowed it and checked it while there, then gave it back. Just disconnect the hose leading up to it. Put the MityVac on. If you squeeze the handle and the SOV lever goes down and stays down for 10 seconds or so, the SOV is fine. But with mine, it went down for a second or two, and not the whole way either, so, it was time to replace.

The rest of the repair is pretty much straightforward. Almost wysiwyg. In my case, I had to disconnect the cruise control lever, the Alda, and a few other parts to get to it. Once that was done, put the part in carefully (read Prayton's post), and be prepared for a runaway diesel. That means, once you start your car, it's going to run full throttle and basically blow up in very short order. It probably won't happen, but be ready. To be ready, you have to block any air from coming into the crossover tubes. I had a stiff piece of cardboard to put inbetween where 2 of the tubes come together.

Good luck, and be safe. It's not that bad of a job, a bit trying, but you'll be a better man, or your wife a better woman, after doing the job. Send her on a mission to fix it for you.

Jeff 1991 300d, 115k

I've got the MitiVac, but I think I'll read Prayton's post before I begin...cdplayer also mentioned it to me...tell me more about the cross over tubes and using the card board for safe-guarding against the runaway engine...is removing the Alda and easy job...is that what causes the risk of the runaway?

pantherpaw · #26 01-11-2008, 09:38 AM

How do I find this "Prayton" article...I did several searches for it, but no luck...anybody?

kerry · #27 01-11-2008, 09:42 AM

Don't waste your time. There's not the slightest evidence yet that the problem is your shut off valve. Go pull a vacuum on the valve and see if it holds before wasting your time figuring out how to fix a problem that might not exist.
My wife wouldn't suck the hose either. Had to switch cars when I had it rigged that way due to the fact that it was too cold outside to trace down the vacuum leak.

pantherpaw · #28 01-11-2008, 12:11 PM

Quote:

Originally Posted by kerry

Don't waste your time. There's not the slightest evidence yet that the problem is your shut off valve. Go pull a vacuum on the valve and see if it holds before wasting your time figuring out how to fix a problem that might not exist.
My wife wouldn't suck the hose either. Had to switch cars when I had it rigged that way due to the fact that it was too cold outside to trace down the vacuum leak.

I cant see any obvious vacuum lines going to the place where they said the SOV is...they said its between the back of the IP and the oil filter housing, but I didn't see the part at all...is it up underneath or something...my service manual cd doesn't mention the valve at all...

pantherpaw · #29 01-11-2008, 01:36 PM

nevermind about that last post...i found it....DA! The vacuum line was stretched and oily, so i replaced it...and it seems to be slightly better, but still not fixed...

I will have to find my vacuum pump and check to see how much mmHG it takes to operate the valve.

pantherpaw · #30 01-11-2008, 02:44 PM

Also, I may not have mentioned that sometimes it shuts off immediately, sometimes it hesitates about 10 seconds then almost shuts off, then starts up again, then pulses the same a few more times before finally shutting off...AND...sometimes, it just will not shut off at all no matter how long I wait, and thats when i have to push the STOP button under the hood...I seems to shut off sooner after the engine is warm...

does this behavior point more specifically to any of the solutions presented so far?