An otherwise good running OM617

[ashedd]

I am just thinking out loud here.. please join in/comment if you feel the need.

I have this '85 TD that up until last winter ran GREAT. I mean it has like 1* of chain stretch, it's starts right up in the cold, it's fast(seriously it is), I use to drive it to Detroit quite frequently.

Sometime last winter I needed to drive the TD, I think I had a flat on my DD.. anyway, 4 miles in to my 8 mile trip it started running rough. It was all I could do to keep it running by the time I got to my destination. I was having to rev it pretty good at stop lights. I finally(lot's of pedal pumping) got it started for my trip home, same thing.. barely made it home.

I settled on lift pump/primer failure. I ordered a new primer and lift pump spring kit. Got it running and it started doing the same thing, running very very rough. I could see that the primary filter was "draining" while running then filling back up once empty. The gap in fuel was causing air to go through the IP. It would smooth out when the filter filled with fuel. So I cleaned the tank screen, drained the tank, blew out the hardlines with compressed air, pulled a vacuum on both the feed and return with no leaks noted. Hooked it all up, same thing. I then decided that I had the rubber lines(which I replaced all the rubber lines) at the tank mixed up. I traced the lines, looked at pictures and got them as they should be. Same engine issues. So I figure I have a hole in the feed line somewhere, they look pretty bad in spots. I test the theory with a remote container of fuel being fed to the lift pump. It ran fine for about 20 mins like that.

Fast forward to today. I had it running off a remote container and it started the same old crap. I thought perhaps this diesel I had was bad, so I go fill my can/remote tank with fresh D2 from the gas station. Get home and it's still running rough. Then the primary filter started doing the fill and empty cycle again, THEN it died. I could not keep it running with the throttle, normally I can.

I primed the poop out of it till the return line ran clear new D2 in to a jar. I cracked all the injector lines till fuel started squirting out while cranking. I tightened them all down... crank.... crank..... crank, I run the batt down three times. Nothing!! It's charging again now.

My general feelings:
I have been slowly working on it to sell. If I can't get the thing to run, then it's a lost cause. It's in the way, I'm sick of looking at it. I am toying with the idea of calling the scrap people to come get it. Problem is it's got lots of new parts. Do I pull those off and sell them? Try to part it out? Keep jacking around with it to get it to run? I would imagine that my next steps to getting it to run are: Check compression(remember it ran great originally), swap out IP's(which I don't have a spare for a 617), pull valve cover and check valves.

There are a few things I think that are worth a few bucks: Bosch Euro headlights w/orange turn signals, New water pump(?), brand new(never been driven) down pipe, SLS shocks, SLS pump, new R4 compressor, Just put new motor mounts on it yesterday(dunno if I want to pull them off).

So what are your thoughts?

[tangofox007]

Originally Posted by ashedd

I settled on lift pump/primer failure. I ordered a new primer and lift pump spring kit.

What, exactly, did the "kit" include? Your symptoms sound a lot like a sticking fuel pump suction valve.

[ashedd]

Plastic "valves", springs and maybe copper washers. I thought I was getting a rebuild kit but I guess that is something different. I had my old, dead reliable, SD here at the time but I was too lazy to pull the lift pump off of it and test it on my TD . I have since sold that old rusty SD, and I miss it. My TE gets crappy crappy MPG's.

[tangofox007]

I replaced the valves and springs in my fuel pump ('82 300D.) It was like having a new engine. Or at least another 15 hp. Original symptoms were slow starting, sluggish performance for the first block of driving. And I could see the fuel moving backwards when using the hand pump. And performance was much better on a full tank than a near-empty one.

[jt20]

Originally Posted by ashedd

I primed the poop out of it till the return line ran clear new D2 in to a jar.

First problem. If you managed prime poop out of it, there's definitely something awry other than the fuel system.

Personally, I think you're giving up waayy too quick. Last summer, the very same symptoms struck my engine dead going up a very steep hill (ie.. high fuel demand).

I primed, I tightened, I replaced washers and the relief bolt... it started great... then died.

WTF happened? Primed again, same thing.

It was the crush washer on the primer pump. Somehow jiggled itself loose.


----------


If I was you:

-Replace the pressure relief bolt

-Check all fuel banjo fittings and replace , or at least, flip over all the crush washers.

-Make sure none of the hard, clear fuel lines around the IP can spin easily at the banjo connection. Thats a good indicator that the plastic line does not have a good seal on the metal.

- O-rings on the fuel filter bolt

-at night, use a flashlight and put it on the clear fuel lines to look for bubbles.

- tighten everything again and mark each one off on a list as you finish

[ashedd]

I'll be honest since I seriously doubt I will ever sell this car to a forum member..

I was hoping to get $1500 for the car. But a MB person would never pay that. The rust is pretty ugly, but it looks good. The tailgate is very rusty with holes, the pass fender bottom has a rust hole, both rear wheel well corners have large rust holes. Then there is the floor.... I think there are 3-4 holes the size of your hand. And the interior is pretty worn out. The car has 302K miles on it, but otherwise ran good.

I fear that once it's running again I will be hard pressed to find someone to give me much over $500 for it

So I dunno...

[ashedd]

Originally Posted by jt20

the relief bolt...

If I was you:

-Replace the pressure relief bolt


-at night, use a flashlight and put it on the clear fuel lines to look for bubbles.

Pressure relief bolt is a new one on me. What exactly is that? I will also do a search.

Clear lines???? mine are all brown/orange... doubt I could see anything through(or is it threw?) them.

Thanks for the help

[tangofox007]

Originally Posted by ashedd

Pressure relief bolt is a new one on me. What exactly is that? I will also do a search.

Right side of the IP, where the return line attaches. But that would not explain the supply line draining, upstream from the fuel pump.

[jt20]

I agree w/ tango that the relief bolt will not be the primary cause for this failure, but it could certainly exacerbate an air ingression.

Next time you have the engine running, run fuel hose from the injector return lines into a container and cap off the barb on the 3-way banjo bolt that lies face down on the fuel filter housing. (the white line on the left in the photo)

[ashedd]

I am going to cut my losses and part it out. I have a thread in the parts section. I am sticking with w124's.

Thanks for the help guys.

[panZZer]

Originally Posted by ashedd

I'll be honest since I seriously doubt I will ever sell this car to a forum member..

I was hoping to get $1500 for the car. But a MB person would never pay that. The rust is pretty ugly, but it looks good. The tailgate is very rusty with holes, the pass fender bottom has a rust hole, both rear wheel well corners have large rust holes. Then there is the floor.... I think there are 3-4 holes the size of your hand. And the interior is pretty worn out. The car has 302K miles on it, but otherwise ran good.

I fear that once it's running again I will be hard pressed to find someone to give me much over $500 for it

So I dunno...

Yup , I got a pretty little 81 teal green CD to go but dont want to deal with an insider either, just a new guywith some cash like I was when i bought it.