I have a spare injection pump that the previous owner said was almost new. I am thinking of putting it on my 1985 300D, but was wondering two things. First, is there any way to determine whether the pump is as good as represented without putting in on the car? Second, is there anything I should do to clean or pre-lube it before firing it up? It has been sitting in a dusty shed for the last four years.

Yes, an injection pump repair shop can run it on a test stand.
What is your location?

Gilly

An injection shop will check it out for about 250.00. It is a lot of trouble to bolt it on to have to take it off again to have it repaired. I was thinking of building my own test stand, but with all the special fittings and the H.P to turn the pump, it would not be cost effective. If you want to take a gamble, as I have, bolt it on. I would make sure it turns, and the throttle arm should easily move before doing so.



PeterG

I don't think it would be that much just to run it on the test stand. Maybe if it needs some work done it may add up to that much.

Gilly

I am in Leesburg, Virginia, not far from Washington, D.C. or Frederick, Maryland.

I would definately spend the money and have it run on a test stand. There was a post a couple of months ago by a fellow member that bought a used pump, installed it, and it ruined his engine because it went full throttle and wouldn't shut off. At the very least, check the shut-off valve for proper operation.

STOP!!!!!!!! DON'T START ENGINE BEFORE READING THIS!!!!!!


Regardless of whether or not the pump is tested by the shop, do the following test BEFORE starting the engine! After complete pump installation, connect a vacuum source like a mity vac to the shut off diaphragm on the back of the pump. When applying vacuum to this diaphragm, the STOP lever should move as if you were pushing it with your hand. If it does not move DON'T START THE ENGINE!!!!!!!!!!!

If you do start the engine and the stop diaphragm is not connected internally, the governor mechanism is not captured and the engine will run away to max RPM with no way to start it except opening the injector lines and doing it VERY QUICKLY.

Even after checking the shut off. Have a 17MM open end in your hand before starting. If the engine were to run away, quickly open the lines at the injector enough to relieve pressure. This will make a mess, but will save your engine. You don't need to remove the line, only a half turn or one turn will relieve pressure.

Don't ask how I know all this. I will just say that I learned it too late, you now have the benefit of knowing this earlier than I did.

Good luck,

According to Yahoo, this place is about 40 miles from you, take it there:
http://www.dieselpump.com/

(in Temple Hill, MD)

Gilly

Thank you.

Better, quicker and less messy way to stop runaway engine is to block off the intake airway.

Take off the air hose to the air filter to be prepared. If the engine runs away, just cover the air cleaner intake with small flat stiff anything such as a board or heavy cardboard. Engine will stop immediately.

P E H

P.E.,

Sorry but that won't work as you described it. Been there, done that! There are too many air leaks around the air cleaner plus the EGR.

When I had my mishap, I ripped that hose off and covered the intake to the air filter and I only lost about 1/2 its RPM. It was getting hot very fast and I had to bale.

If you are to rely on blocking air, you better have the air filter assembly off and EGR plugged. Believe me, once it gets max RPM, you will have to block ALL air or you won't kill it. Been there, done that.

Have a great day,

Larry, I was chatting this morning with a local MB tech and asked him about the scene you described. I knew he had an experience with a runaway Mercedes diesel.
He said he was working at a dealer in New York in 1978 and one of the techs replaced the vacuum shutoff on a 123. None of them were aware of the potential for a runaway engine at that time, and so no precautions were taken.
He said the tech started the car and then walked over and began filling out some paperwork. He said the engine started to slowly build up speed, and by the time the tech paid heed the engine was running at a very high RPM.
He thought there would have been enough time there early on to have pushed the stop lever in and effectively shut down the running, but the delay by the tech prevented that.
Is that what you saw, or did the one you have just take off out of control right off?

Larry,

I Never tried it on an EGR engine, but it always worked on non EGR engines. Even if it reduces the engine speed to 1/2, that would keep from damaging the engine until some injection lines could be loosened.

I was in the Army and one time a self propelled Diesel powered Howitzer engine ran wide open and couldn't be shut off. A poncho in the air cleaner caused the engine to shut down.

Sounds like another good reason to block off the EGR valve.

P E H

You could also pinch off the fuel hose that runs into the suction pump, down by the prefilter. Or barring a handy needle-nose pliers or something to pinch it off with, one good tug on the prefilter would probably just pull it off the suction pump, or the hose would seperate from the prefilter. A little messy, probably about the same as loosening all the injection lines, and a bit faster.

Gilly

ps When I went to tech school for Diesel mechanics, the instructor just had a lunch tray handy that he liberated from the school cafeteria. He wrote "The Big Switch" on it with a marker. That's what he used for handling runaway Detroits. He started using that after one of the guys used some shop towels and they had to pick pieces of shop towels out of the turbo and blower.

OKAY GUYS!!!!!!!!!!!!!!!!!

Go read the thread I started shortly after my disaster.

Covering the intake snout on other engines may very well work but it didn't on mine and don't expect it to work on any other 616 or 617. Been there, done that!!!!

There is plenty enough fuel in the pump to run the engine at high RPM to destroy the engine. Pinching the fuel line will do nothing.

Go back and read what I said in the first post of this thread. When the shut off is not hooked up internally the governor runs away and the stop lever is INEFFECTIVE. I cut my hand pretty bad from yanking around on the linkage so hard. THAT'S WHY I SAID TO SEE THAT THE STOP LEVER WORKS WHEN APPLYING VACUUM TO THE PUMP.

Folks I have been there and done that. I posted my experience at the expense of SERIOUS PERSONAL EMBARRASSMENT in the hopes that it would prevent someone else from destroying their engine. So, if you don't want want to listen to me then don't.

I don't remember the name of the thread, but if you will read it you will understand what you need to know to prevent this from happening to you.

Unless you've been in the situation and lost a recently rebuilt engine that you put your all into, then don't second guess my warnings without knowing what the H$LL you're talking about!!!!!!!!!

Have a great day,