I have an 85 300D, the vehicle lost power and shut off while driving. It would not start again. I performed the following troubleshooting:

-New fuel filters, Primed system, No start.
-Added 5 gallons of Fuel to tank, primed system, No start.
Towed car home...Started Reading the forums.
-Cracked air bleed valve at filter housing and cranked, fuel pulsed out of the valve.
-Cracked Injector 1 nut and cranked (WOT), NO FUEL TO INJECTOR.
-Cracked remaining injector nuts and hard lines at IP and cranked, No fuel coming from IP.

After researching the forums, I'm still not clear on how to effectively troubleshoot the Lift Pump. If the Lift pump becomes dry, does it need an isolated priming procedure? How likely is it to be a mechanical failure?

I used a jumper car while trying to start the car to keep the starter going, and cycled my functioning glow-plugs every time. The tank is 3/4 full of Diesel.

What type of primer pump do you have, the "twist" and prime or the "push" and prime?

I don't know what the "air bleeder valve" is??

But if you cracked a line, that allowed all the fuel to drain out of the ip, it will take a bit of hand priming, cranking etc to prime all the air out of the injection pump....specially with new filters...

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Hey coolj, thanks for responding!

I have a black, later style prime pump. I see it moving fuel well in the primary filter.
The "Air bleeder valve" or fuel bleeder, this is a common diesel/heavy equipment term, a general one for a valve used to bleed air out of the fuel system and prime it. In the case of this motor, I used the banjo bolt at the top of the filter housing, usually works well for me whenever having to prime the system.

How does air get introduced into the IP system? Are there more common causes?

There are three bajo bolts ontop of the fuel canister plus the one bolt that holds the spin on filter on.

The three banjo bolts, plus the canister filter bolt shouldn't be touched as that can lead to air being introduced...

Typical when a person changes the spin on filter, they will fill the new filter with clean diesel or purge/seafoam. Tighten it down and prime a bit...Then start the car, while holding the accelerator down...Until the engine runs smooth...

If you don't fill the filter with air, even pumping the primer for a half n hour may not remove all the air...

What you do is, to crack the hard lines at the injectors...Crank the car while you or a helper looks for fuel to come out of the hard lines and then start to tighten them down in the order fuel is seen. This will rid the system of air...

Air can be introduced in the system by the users, bad crush washers/seal ring, oring on bolt that holds spin on fuel filter, and hoses. Very seldomly air can also get in on the element housings as the type M pump has rubber origins and both M/MW have crush washers.

If you have a good battery, try to purge the air from the injection pump as described above..

Since you have been using a banjo bolt as a bleeder, there is a good chance a crush washer/seal ring is bad....

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I have read pages of threads regarding fuel delivery issues. If its been said before on here, I tried it. Right now we (Diesel Mechanics) have a diesel purge IV hung from the hood and a line going directly into injection pump. Forget starting the car, just seeing the pump move fuel is our intent. All hard lines are disconnected.

The Haynes manual troubleshooting no longer applies to this situation.

I don't use the Haynes manual, I use the FSM that are published by mercedes themselves. Here is a link...

W123-dokumentacja cz. 2

The injection pump, will not move fuel with out the car running/cranking to power the lift pump to pressurize the injection....

These cars work a lot different then american diesels or tractors...

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The priming pump moves fuel through the injection pump and main filter circuit, removing any air. If you installed the new filter "dry" then you'll need to pump and pump and pump to get the air out, OR you can remove the center bolt and fill the filter up with fuel and then you may only need 50 to 100 strokes of the pump to remove any air in the system. You will feel a change in the amount of force required and hear a change in the sound the pump makes (if the shop is quiet) once you have primed the injection pump.

Note that the primer pump DOES NOT push fuel out to the injectors.

If you get all the air out, and suspend the fuel source so the lift pump doesn't need to do anything but pass fuel under pressure (what you describe as the "fuel IV") then cranking the engine and holding the accelerator linkage wide open should get fuel out to the injectors, and if the hard line is loose at one of the injectors, you'll see fuel weep out there.

If the car has been operated with WVO or "biodiesel" or something other than pump diesel, all bets are off, you may need to source a new injection pump.

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Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

Problem solved. Heated the IP with a torch, Removed the injection pump delivery valves, sprayed stuff down, blew stuff out, checked the plungers were moving, topped off and primed everything with Melt Down. Cranked until it idled. Diesel/Stanadyne mix for the fill-up.
I just about gave up on the situation, we tried one more time and the IP started moving fuel to the injectors, we still are unclear definitively, it's running.

Allow this to provide hope for any other person with similar issues.

Need help with similar sounding problem. 1985 300SD.
Started and ran normally until stopped running last week. Weather, 65 degrees, sunny. Drove 2 blocks. Accelerated from stop sign. Lost power, ran rough and engine stopped running in less than half a block. Tried restart several times. Coughed and ran rough a few seconds and died. Gas pedal down runs a bit longer but still rough and dies.
Changed primary and secondary fuel filters. Filled secondary filter with oil. Primed primary until full of fuel. Still no start. Coughs, revs rough a second or so and dies. Use only pump diesel always. New Bosch glow plugs last yr. Never touched in fuel tank filter. Next thing to try will be loosen nuts on top of fuel injectors 3/4 turn and see if fuel comes out.

I am not a pro. From your fix procedure, why does the IP need heating with torch. Is it propane torch or something else? How difficult is removing delivery valves and cleaning out? What is "Melt Down"? What is "Standyne"? Hope to get my old diesel running again. Hope I do not need a new injection pump.
Thanks again.

I wouldn't and I am sure others here would agree....Not to use a torch to "heat" the ip....That is a very bad idea....

I also wouldn't suggest playing with the delivery valves or springs....another bad idea....as there is a crush washer that needs replacing, certain torque procedure etc....

Start a new thread, that way we can help and not continue on this thread...

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Pretty much everything you did is ill advised. Heating the IP with a torch is a horrible idea and specifically condemned in the manual. Removing the delivery valves is a very sensitive procedure and I really hope you didn't mix and match ANY parts between cylinders. You sprayed stuff down and blew stuff out with no delivery valves installed? The parts inside the IP are lapped to the hundred thousandth of an inch. You just introduced particles that will score the precision element bores and cause a loss of fuel delivery. Huuuuuge problem. You filled up with Melt Down which is an emergency use antigel, probably high in percentage of alcohol. That washes away the lubrication of the elements. It's fine to add antigel to the tank when absolutely necessary, but it's NOT OK to add it straight into the IP.

You got it running, but you've seriously abused the IP and I'd be surprised if you go on with zero issues. Next time, utilize the factory manual that Mercedes-Benz wrote for techs and don't do things before making sure they won't cause damage. A diesel tech that's used to working on Power Strokes isn't going to be at home on a Bosch IDI engine...

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'84 190D 2.2 5MT (Red/Palomino) Current car. Love it!
'85 190D 2.2 Auto *Cali* (Blue/Blue) *sold*
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Calm down guys, it is his engine and his risk to decide. He didn't say how hot he heated the IP. Why the need to keep delivery valves matched to IP ports? Aren't they just simple spring-loaded check valves? You do need to insure the parts are oriented correctly (isn't intuitive and FSM photos aren't super clear). That said, I have only removed #1 for drip timing and would keep them matched just for practice, but doubt it would matter. The main thing is to never loosen the 2 clamp-down nuts on the ports. That can throw off the volume adjustments that hopefully someone did on a Bosch injector test machine. As long as he turned over the IP while the delivery valves were out, it should have flowed any debris out of the ports. I have done the drip timing several times and never replaced the brass "crush washers" and have had no leaks. I just polish them a little on 600 grit sandpaper. I think the torque spec is just so they stay tight and don't leak, not rocket science. Does everyone always torque the injector tube nuts? Didn't think so.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

Was this car on alternative fuels like waste vegetable oil? Either currently or in the past to your knowledge?

Heating the IP with a torch is what's bad. It's uneven.

The delivery valves can probably be moved without issue, but if he removed the plunger and such from inside, bad things will happen. I wouldn't even move delivery valves after all this time.

The torque on delivery valves is important. If you tighten them too much, you'll seize break something or mushroom out the crush washer. Too loose and you'll leak fuel internally. On an M pump, torque is CRITICAL. Tighten the DVs too much on those pumps and you'll crack the IP body!

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'84 190D 2.2 5MT (Red/Palomino) Current car. Love it!
'85 190D 2.2 Auto *Cali* (Blue/Blue) *sold*
http://badges.fuelly.com/images/sig-us/302601.png
http://i959.photobucket.com/albums/a...0/sideview.png

But one must remove the innards from the #1 delivery valve to do the drip method of timing the injection pump. That should probably be done every 200,000 miles or so. When you do so, be very careful to note the order and orientation of all the internal parts. You sure don't want to have to unscrew #2 to figure it out. There is a photo in the FSM, but hard to make out the orientation of the big disk.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans