300D Turbo '87 Vacuum Shut Off - PeachParts Mercedes-Benz Forum

reyndiesel · #1 11-26-2005, 11:59 PM

I'm new to this forum. I just bought an '87 300D Turbo, W124, OM603, a 6Cyl, with 277,000mi. It wouldn't shut off and held vacuum back to the ignition with a Mityvac so I got a vacuum shut off valve from ********AZ. The problem is, I'm stuck. I can get the two bolts and brackets that hold the vacuum shut off valve out, but I can't get the, I think its the fuel rack position sensor switch, loose. Its an electrical coupling, three wires going into it a little behind the vaccum valve and in front of the ALDA. Any ideas? By the way, this is my first diesel and first Mercedes and I really like the car. Its really tight, when you shut the door there's no tinny echo like on lots of cars.

whunter · #2 11-27-2005, 12:39 AM

Read this thread before you go any further...

Run away diesel, why does it happen?
http://www.peachparts.com/shopforum/showthread.php?p=824840#post824840

Here is another link that may save you many questions:

Organized MB DIY links
http://www.peachparts.com/shopforum/showthread.php?t=135055

Have a great day.

reyndiesel · #3 11-27-2005, 09:53 AM

Whunter,
Hey, thanks for the heads up on the run away issue. I won't dare start it up without taking precautions. Thanks, too for the DIY links, the mb.braingears one has some great diagrams. Now I see how that vacuum shut off hooks in. I think the electrical piece I'm trying to get loose is part of the control rod travel sensor. It says on the diagram its connected by a 3-pin plug. How do I get it off? Its in the way of the vacuum shut off. Once again, thanks for your help. This is a great forum. I've been reading stuff on it for a couple weeks before I signed up.

duxthe1 · #4 11-27-2005, 02:12 PM

It should have an outer ring that turns counter clockwise. As you turn it (can be very stubborn) it should pull the connector out of the sensor. Don't be surprised if the outer ring breaks, if it does you can simply pry it connector from the sensor. If it does don't sweat it, gravity and tension will hold the harness as it's cooked in this position for over 200k

sixto · #5 11-28-2005, 07:19 PM

When you get frustrated enough, pull the rubber cover off the connector (of course it'll tear), pry up the top of the connector case, note the positions of the 3 pins, remove the 3 pins. That'll probably give you enough room to replace the shut-off valve.

Sixto
87 300SDL

WANT '71 280SEL · #6 11-28-2005, 10:11 PM

On mine, when I went to move the plastic collar, the receiving part started to turn. My resolution was to use a screwdriver and a hammer to tighten the metal base then use the screwdriver and my palm to hit the tab on the collar to turn it. When hitting the tab, hold the screwdriver as close to the inner circle and lightly hit the screwdriver with your palm. Start out gently then go from there to get that plug collar moving.

HAVE A 14MM WRENCH HANDY!!! My 603 ran away 2 or 3 times before I got it right again. The first time it ran away lasted about 30 seconds before I could find a wrench. Of course the well-built 603 wasn't noticeably affected by it, but it was a nerve wracking experience nonetheless.

PM or email me if you have any further questions. If you really are unsure I can give you my cell phone number and I can talk you through most of it as it wasn't too long ago I did it on mine.

Thanks
David

sixto · #7 11-28-2005, 11:21 PM

Test the new shut-off valve with a MityVac. When you apply a vacuum, the stop lever will swing down. You won't have a runaway if you verify the installation.

Sixto
87 300SDL

WANT '71 280SEL · #8 11-28-2005, 11:34 PM

sixto, that test just verifies that the shut-off valve moves the rod like it should. Even if the valve is installed incorrectly the lever will move, been there, done that.

Thanks
David

sixto · #9 11-29-2005, 12:27 AM

False faith on my part? It's always worked for me

I do keep a mouse pad handy.

Sixto
87 300SDL

WANT '71 280SEL · #10 11-29-2005, 10:00 AM

If the valve is on the IP, it is attached to the lever. You just have to make sure that the inner lever is on the proper side of the rack. I think the inner lever is supposed to be on the inner side of the rack towards the side where all the lines fittings are. I had to use a screwdriver to hold the rack out so I could get it all setup correctly. The thing about the 603 is though, that if you don't mess with the inner part of the lever and just R&R the valve, the inner lever should stay on the proper side of the sliding rack. It's just that I didn't really know what I was doing and tried to remove the lever, which means I had to put it back and when I did I never noted what side of the rack it went on.

Thanks
David

AJgeo · #11 11-29-2005, 04:12 PM

I managed to replace the vacuum shutoff without removing the electrical connector you are referring to. I too could not for the life of me get it off, but it did move up about 1cm. The band around mine was already broken. The 10mm bolt behind the shutoff valve was loosened with two different cheap 16 ( I think) point box wrenches with the teeth in slightly different locations. That way, by alternating wrenches, I was able to loosen and tighten with only about 5 degrees of turning space. It is difficult to put in the new one and get the rear tab to line up correctly so it will properly seal on top of the injector. I used very long locking forceps to hold it up from the tiny space in the manifold. I then carefully angled the shut off valve until it sat in place. As I did this, I kept pressure on the manual valve (hooked a heavy wrench on it) so it would be up and "accept" the little hanger on the vaccuum valve. As it sits into injector, the manual valve should lift up a bit. Check it with the mityvac once it is seated. The manual shutoff valve is always connected, run away should not be an issue.
This little job really tested my patience, but it is very satisfying to turn off the key and the car actually shuts off!

reyndiesel · #12 12-23-2005, 08:44 PM

Thanks for everyone's help. I ended up taking the intake manifold off to get the electrical connector out. It turns counterclockwise and its tough to get out. Had to make a really short 6mm hex with a die grinder to get the manifold out. Much easier to get the shut off valve out, though, and I can see what I'm doing. I was worried about a run away. I got a new shut off valve from ********AZ. Couple of problems. First, I got two fiber gaskets with it. The original Benz shut off has a rubber gasket on the base. I don't see how the fiber gaskets will seal and the rubber gasket is getting a little hard with 270,000 mi on it. Also, the arm on the new shut of is longer than the old even when its pushed all the way in. Any ideas? I hate to put it all back together and have it not work.
Thanks,
Brad

sixto · #13 12-23-2005, 09:11 PM

I have no advice re the replacement shut-off valve but IIRC the shut-off valve has an o-ring, not a flat gasket. Consider replacing the glow plugs while they're accessible.

Sixto
87 300SDL

AJgeo · #14 12-23-2005, 10:09 PM

I think you could probably take the old rubber o-ring to an auto parts store and they should be able to match the size. I think you really need to use an o-ring. I would install the shutoff valve and test the action with the mityvac. The red "off" lever should move and hold to indicate it is functioning properly when you apply vacuum. The glow plug replacement mentioned earlier may not be a bad idea, especially if you have no records indicating when they where last changed.
Good luck!

whunter · #15 12-23-2005, 11:52 PM

Quote:

Originally Posted by reyndiesel

Thanks for everyone's help. I ended up taking the intake manifold off to get the electrical connector out. It turns counterclockwise and its tough to get out. Had to make a really short 6mm hex with a die grinder to get the manifold out. Much easier to get the shut off valve out, though, and I can see what I'm doing. I was worried about a run away. I got a new shut off valve from ********AZ. Couple of problems. First, I got two fiber gaskets with it. The original Benz shut off has a rubber gasket on the base. I don't see how the fiber gaskets will seal and the rubber gasket is getting a little hard with 270,000 mi on it. Also, the arm on the new shut of is longer than the old even when its pushed all the way in. Any ideas? I hate to put it all back together and have it not work.
Thanks,
Brad

It is possible that you received the wrong part, do not try to install until it is verified.

Call Phil at FastLane with your VIN# and the new shutoff valve part number.
Questions about Parts?
Call Phil for help at
1-888-333-4642
Mon-Fri 10:30a-8:00p ET
(NOT for technical support)