Diesel RVs: Re: [diesel_mercedes] Loping OM616 injection pump test video

Just so Bogy ;

It can have a lot of crud in there gumming things up plus water drops too big to allow the passage of fuel ~ I found both plus rust , I *think* the rust may have precluded the valve from working properly .

The steel pipe is a red herring ~ if the cylinder gets sufficient fuel to run off idle , it's passing plenty of fuel and isn't blocked .

I was told the discharge volume is the primary change made when fiddling with the 13MM nuts and plate .

Timing is critical too .

Maybe Brian can find you a used 616 IP *BUT* I recently tried chattnig up a fellow who was removing the IP from an '85 300D , he was fairly pleasant but made it clear he had NO IDEA how to check for a good used pump and was only taking it to re sell on E-Bay so CAVEAT EMPTOR ! .

BTW : I too prefer to learn thed hows and why's of things before making repairs , most of the time when I mention teaching myself it means I already have several spares , all the Tech info and books I can find plus lots of discussions under my belt .

Knowledge is worthless unless shared .

-Nate
Bogy wrote :

Nate:

Are you then suggesting, possibly, that perhaps the check valve is not seating properly? What else could be wrong inside there. Forgive me, but it is my nature to want to know WHY something is the way it is - not just WHAT to do or not do. By the way, I can get fuel to move down the line to bleed the line when reassembling. So there is fuel moving out toward the injector when the line is "open" or "cracked open" at the end, but not when the injector is tightly attached.

It's too late for me to not touch the 13mm ATF nuts. That is how I equalize fuel delivery on a per stroke basis between the outlets. 5-6 revolutions of the shaft produces less than 1 mm of difference in the height of the fuel (in clear plastic pipes 3mm in diameter) across all four outlets by rotating these outlets. I know it affects the injection timing too. so what is more important - exact timing or amount of fuel delivered?

I have had 2 new intake screens on this rig in the last 400 miles. I have also taken off the tank and cleaned it out thoroughly. There was a trace of water in it and some of that was getting into the intake screen and even the main filter. I always pour out the contents of my fuel filters when I change them. Amazing how much water can be in the bottom of those things. That is why I pulled and cleaned the tank - I noticed some water in the clear intake screen.

Otherwise thanks for the hope that it is only a dirty or faulty outlet part.

Bogy.

"Hardware eventually fails. Software eventually works" - Michael Hartung

From: "vwnate1@... [diesel_mercedes]" <diesel_mercedes@yahoogroups.com>
To: diesel_mercedes@yahoogroups.com
Sent: Sunday, July 31, 2016 7:44 AM

Subject: [diesel_mercedes] Loping OM616 injection pump test video

Very good Bogy ;

Now , remove the # 4 injector pipe from the IP and using a 15 MM six point deep socket , remove the delivery valve and swab down in the open hole with clean Q-Tips and some brake cleaner or engine starting fluid ~ the amount of crud and tiny water drops I found in my worn out IP amazed me .

The elements in the delivery valve were also rusty (!) before I found good one , I made do my wire brushing them well before washing HOSPITAL CLEAN then re assembling .

DO NOT touch the two 13MM ATF nuts on the top of the IP !! .

Failures like this are why Mercedes wants you to use a CLEAR PLASTIC fuel intake screen .

Change it ASAP , Auto Zone and Pep Boys both stock the correct clear plastic version .

-Nate
Bogy wrote :

Let's see if this works.

"Hardware eventually fails. Software eventually works" - Michael Hartung

__._,_.___

Posted by: vwnate1@yahoo.com

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