Replacing the Injector pump shut of valve and preventing a run away engine - PeachParts Mercedes-Benz Forum

dmorrison · #1 04-21-2006, 11:29 PM

I made this addition to the post below.

IP control rod/shutoff link-need help!

I figured a separate post would be good for the forum

I want to add to this post since I just replaced my IP (injection pump) shutoff valve.

This information is for a 617 motor, I have a 82 300TD.

If the shutoff valve is not properly installed the shutoff rack in the IP is not controlled and this situation will allow a runaway engine upon startup. ( A runaway is when full fuel is provided to the cylinders, much like a full throttle, and the engine will accelerate to its maximum RPM with no control of the IP. The engine will run at max RPM, until it fails.

Talking to two of the more experienced mechanics at the local dealer as well as reading the posts here I want to make the following post and pointers for the job.

When purchasing the injection pump shutoff valve, make sure you purchase 2 gaskets. One for either side of the shutoff valve washer.
Also consider the following
New vacuum lines and connectors, if old.
Mounts for the air cleaner, since you will remove it for a safety test.
Rubber oil hose for the Turbo, broke mine, it was so old and hard, and your there.
Inline filters for the vacuum system to look for oil.
Vacuum pump rebuild kit, if lots of oil in the tube to the pump
Ignition key shutoff valve if oil is in there too.

The Valve

http://catalog.eautopartscatalog.com/mercedesshop/sophio/quote.jsp?clientid=catalog.mercedesshop&cookieid=1S91C0VJ61S91C126B&baseurl=http://catalog.peachparts.com/&partner=mercedesshop&year=1982&product=D2020-11537&application=000004567

The Gasket

http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1S91C0VJ61S91C126B&year=1982&make=MB&model=300-TDT-001&category=D&part=Shut+Off+Valve+Gasket

Take a picture of all your vacuum connections, 3 ways and 4 ways, it makes it easier to install them when you know where they go. You will have to remove some of the vacuum lines for the job.

I removed the fuel lines to each injector. It made access to the rear of the IP easier.

I also removed the IP vacuum control valve by unbolting the 2 bolts and disconnecting the ball socket at the lower arm of the IP. Don't want to break this, it's expensive ($170).

The Vacuum control valve

http://catalog.eautopartscatalog.com/mercedesshop/sophio/quote.jsp?clientid=catalog.mercedesshop&cookieid=1S91C0VJ61S91C126B&baseurl=http://catalog.peachparts.com/&partner=mercedesshop&year=1982&product=D2032-15990&application=000004530

To remove the shutoff valve there are 4 bolts holding a square bracket on. I used a combination of a close box end ratchet, a 1/4 drive ratchet and a normal closed box end wrench. Its a tight squeeze on the 617, more room on the 616. Unbolt the 4 bolts and to remove the unit. I found the only avenue usable, due to its size, was to move it along the block towards the rear of the engine, between the oil filter housing and the block. On the 616 this is not a problem.

Once you have the unit out, don't push on the lever, If you had an oil leak it will squirt the oil out through the small hole. It goes everywhere.

Clean the washer and mounting surface on the IP block Install the 2 new gaskets on either side of the washer, install the washer on the shutoff valve and slide it along the block to position it in the hole. Now install the clamping base over the shutoff valve to position it. The sharp edge goes towards the IP block

Installing it correctly---- the 90 degree bend in the shaft goes towards the engine block. The vacuum hose hole is on the top. Here is a good way to insure that it is connected correctly. Sweep the lever from the drivers fender towards the block as you are seating the base of the valve onto the IP block. To check to see if it is correctly attached to the rack, use your Mityvac ( you should have a Mityvac if you own a Mercedes diesel) to apply vacuum to the shutoff valve. Once you apply the vacuum, try to pull back on the shutoff valve and see it if will separate form the IP block. If it does not then you have installed it correctly, if it does, then try it again. LEAVE the mityvac applied to the shutoff valve, it will hold the valve in position. Install your 4 bolts. The new bolts have sealant on the treads due to the oil in the IP. If your reusing the old bolts then apply some RTV.

Now for a couple of tests to see if it working before you install everything you took off.

Since the IP lines are removed form the IP pump to the injectors you can crank the motor and not much can happen (won't start). I used a Plexiglas shield over the top of the IP output and had the wife crank the engine with both the shutoff valve in the off position ( Mityvac with vacuum applied) and the on position. In the on position the outlets will spit at you. Very low volume but high pressure. The shield helps. When off, the amount was decreased by about 80%, Not completely off, but reduced. Try this test just in case you have to reinstall it. It's a pain with everything reinstalled.

Reassemble everything and remove the air intake and 180degree tube from the air filter to the turbo input. Have a piece of wood that you can place over the turbo inlet to shut off the engine, just in case you messed up the installation and might have a runaway engine. Also have a 17 MM wrench available to loosen the Injector lines if the board will not shut it down completely. The board will control the RPM due to lack of air, but a complete shutdown may only be achieved by the loosening of the injector lines. ( not sure about this theory, my installation was correct so I did not have to test it. But with the board over the intake the engine RPM will be low or 0)

Another approach I had. when ready to test the engine, apply vacuum to the shutoff valve. Have your wife/friend/etc start the engine (don't forget the glow plug cycle). With the vacuum applied it should not start, If it does your standing right next to the turbo. Apply the board and if that does not shut it down then loosen the Injector lines. Doing it this way your attacking the engine at a low RPM and stopping the air right away not while it at 6000RPM.

After the test above start the engine without the vacuum applied. It should run normally since it did not start and run away on the previous test.

Additional notes.

The correct wrench is helpful with the injector lines ( of course I used a regular open end wrench, I will order one of these).

This wrench, scroll down to H4550

http://www.peachparts.com/diy/mb_tools/mb_tools.php

Make sure you run the engine to make sure the injector lines are not leaking. If your rough on the injector overflow rubber lines, they may leak. If you have lots of rubber then try cutting new ends, if not then replace them.

This job was not as bad as I had made it out to be in my mind. Using the Mityvac to make sure the unit has made the correct connection allows you to do this job without worrying about a runaway engine. I would do it again without a second thought.

If the valve has leaked oil into the system you will need to disconnect the lines at various point to see how far it has progressed. If it got into the vacuum pump, the manual recommends rebuilding it, the same for the booster and all the other components. Determine how much oil has progressed through the system and figure out what you want to do.

Dave

PS
When you install the valve correctly, the "STOP" lever will not move while applying vacuum to the shutoff valve. Moving the "STOP" lever to test the installation is not a valid test. I move the lever with both vacuum applied and not applied and could tell no difference in the action of the STOP lever. This applies to the 617in the 82 300TD.

#2 02-08-2008, 05:18 PM

Replacing the shutoff actuator is an easy job, nowhere near the risky/dangerous operation as some would have you think. You would have to make several obvious mistakes in a row to get a runaway.