Yeah, the linkage that connects to the IP, at the IP there is a bellcrank attached to the shaft which runs into and through the IP itself. I don't recall exactly how the bellcrank is attached permanent or held in place with a nut or something similar. You would want to using a mirror I'd guess make certain the shaft turned when the bellcrank is rotated.

It seems illogical that the linkage or bell crank are the cause of this particular problem as the engine would normally start an run with the throttle not actuated at all, but it's prudent to check as the obvious and simple things before diving deeper into the IP. Unlikely but it could be something has occured that no one has observed before.

You've eliminated the IP vacuum shut off because you've removed it completely if I read your posts correctly. One thing that I would check before opening up the IP would be to remove and inspect the ALDA, it's concieveable that it has somehow failed mechanically and a piece or part of it has dropped down and is somehow interfering with the rack, unlikely but? The ALDA mechanism responds to pressure which causes it's internal Bourdon chambers to be compressed allowing it's actuator pin to rise and thereby stop impeding the rack's movement. It's concievable that something has failed and as a result somehow the rack is impacted. Removing the ALDA would serve to eliminate it as a possibility of something that affects the rack's free movement, again unlikely but you're faced with trying to most easily eliminate the potential problem sources before diving into the IP.

OM601, 602, 603 Lift pump Repair kit



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__________________
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1983 300D
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Lift pump removed and dissassembled....

there appears to be no service parts...I expected to find a rubber diaphram or something that could be removed, inspected, replaced, etc....

there are two check valves of some type but there seems to be no way to take them apart to inspect the actual rubber parts...

One valve is the top, output fitting...I can easily blow through it but can't suck anything at all back through it...so I would venture to say that the output side holds good fuel pressure.

The other check valve that is operated my the IP driven piston also I can blow through easily but can't seem to suck any air backwards through it...this is the check valve that actually moved back and forth thru the lift pump body, first drawing fuel into the pump body on the back stroke, then forcing it through the first check valve on the forward stroke, and finally forcing it through the second "output" check valve on the next back stroke as it simultaneously draws in the next gulp of fuel into the main pump body.

I'm no expert but I believe the lift pump is fine...

I guess I will be removing the side plate on the IP next and seeing what I observe on the "rack" thing...

__________________
1987 300TDT
1981 VW MKI Caddy 1.6 diesel, waiting on engine swap
1983 D-50 Power Ram 4x4 "Mitsubishi" 2.3 turbo diesel
assorted gas powered crap and motorcycles

RIP: 1984 300TDT, 1982 300TDT, 1984 190D 2.2, 1992 300D 2.5, 1987 300TDT, 1982 Maxima LD28, 1983 Maxima LD28, Isuzu C223 P'ups X3, 1983 Holiday Rambler 6.2 Banks turbo diesel, 1984 Winnebago LeSharo 2.1 TD, 1985 Allegro 6.5

I had removed both the ALDA and vacuum shut off and tried cranking it...still no fuel delivery

__________________
1987 300TDT
1981 VW MKI Caddy 1.6 diesel, waiting on engine swap
1983 D-50 Power Ram 4x4 "Mitsubishi" 2.3 turbo diesel
assorted gas powered crap and motorcycles

RIP: 1984 300TDT, 1982 300TDT, 1984 190D 2.2, 1992 300D 2.5, 1987 300TDT, 1982 Maxima LD28, 1983 Maxima LD28, Isuzu C223 P'ups X3, 1983 Holiday Rambler 6.2 Banks turbo diesel, 1984 Winnebago LeSharo 2.1 TD, 1985 Allegro 6.5

I removed the side plate from the IP...the rack moves very freely...the throttle lever moves it forward and the manual fuel cut off lever moves it backwards....I'd say the IP rack is fine...

I'm pretty sure the lift pump is good...

next I'll finally pull that check valve on the back side of the IP....but looks like I gotta pull the intake manifold or at least some of the injector lines to access it...

__________________
1987 300TDT
1981 VW MKI Caddy 1.6 diesel, waiting on engine swap
1983 D-50 Power Ram 4x4 "Mitsubishi" 2.3 turbo diesel
assorted gas powered crap and motorcycles

RIP: 1984 300TDT, 1982 300TDT, 1984 190D 2.2, 1992 300D 2.5, 1987 300TDT, 1982 Maxima LD28, 1983 Maxima LD28, Isuzu C223 P'ups X3, 1983 Holiday Rambler 6.2 Banks turbo diesel, 1984 Winnebago LeSharo 2.1 TD, 1985 Allegro 6.5

IMO, until this is resolved, further diagnosis is not possible.

The FSM is clear, the word "Minimum" is deemed irrelevant by other members, when it is critical to correct function per Mercedes Benz.

A minimum delivery quantity of 200CC in 30 seconds must be attained.

My best guess is the lift pump is so weak it is allowing air pockets in the injection pump fuel body = the area that supplies your delivery valves = no fuel bypass means no self purge of trapped air in the fuel body.


.

__________________
ASE Master Mechanic
https://whunter.carrd.co/

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
2003 Volvo V70

https://www.boldegoist.com/

I'm a certified dumbass....GP relay fuse blown....

grabbed one from an old spare relay and it fired right up...

the fuse is so oxidized I can't read the rating...it is 50 or 80 as I recall...I'll need to buy some spares

__________________
1987 300TDT
1981 VW MKI Caddy 1.6 diesel, waiting on engine swap
1983 D-50 Power Ram 4x4 "Mitsubishi" 2.3 turbo diesel
assorted gas powered crap and motorcycles

RIP: 1984 300TDT, 1982 300TDT, 1984 190D 2.2, 1992 300D 2.5, 1987 300TDT, 1982 Maxima LD28, 1983 Maxima LD28, Isuzu C223 P'ups X3, 1983 Holiday Rambler 6.2 Banks turbo diesel, 1984 Winnebago LeSharo 2.1 TD, 1985 Allegro 6.5

What about all the ongoing claims of "no fuel delivery"?

You cannot have led us that far astray............the vehicle had to have fuel delivery.............

All of the above statements had to be complete BS.............

well that really puzzles me...I cracked hard lines and got nothing more than some residuale fuel draining...cranked an nothing noticed...I expected high pressure spray...I really screwed this trouble shooting episode up...

sorry guys but I am a certified dumbass on this one...

the first times I checked for fuel I guess I assumed massive quantities for only a few seconds cranking...

doing the 30 sec test into a measuring cup was later...tried starting it again and still no start...

I totally F***-ed up not double checking the GP fuse :-(

totally my bad on this guys...I'm not ashamed to admit I'm a dumbass...but I am :-(

__________________
1987 300TDT
1981 VW MKI Caddy 1.6 diesel, waiting on engine swap
1983 D-50 Power Ram 4x4 "Mitsubishi" 2.3 turbo diesel
assorted gas powered crap and motorcycles

RIP: 1984 300TDT, 1982 300TDT, 1984 190D 2.2, 1992 300D 2.5, 1987 300TDT, 1982 Maxima LD28, 1983 Maxima LD28, Isuzu C223 P'ups X3, 1983 Holiday Rambler 6.2 Banks turbo diesel, 1984 Winnebago LeSharo 2.1 TD, 1985 Allegro 6.5

your Mark Twain signature quote is most appropriate...

__________________
1987 300TDT
1981 VW MKI Caddy 1.6 diesel, waiting on engine swap
1983 D-50 Power Ram 4x4 "Mitsubishi" 2.3 turbo diesel
assorted gas powered crap and motorcycles

RIP: 1984 300TDT, 1982 300TDT, 1984 190D 2.2, 1992 300D 2.5, 1987 300TDT, 1982 Maxima LD28, 1983 Maxima LD28, Isuzu C223 P'ups X3, 1983 Holiday Rambler 6.2 Banks turbo diesel, 1984 Winnebago LeSharo 2.1 TD, 1985 Allegro 6.5

The issue was your expectation of a "high pressure spray" from the IP.

For everyone else on the thread, and yourself, there is no high pressure spray from the IP. It only delivers a very tiny measured quantity of fuel on every revolution. From a quick calculation, each barrel would deliver .0006 ounces of fuel per revolution at an average road load (2 gallons per hour). It would deliver much less at idle. So, you can expect the tiniest dribble of fuel out of the hard lines...........nothing more.

Ahh........forget it...........we all screw up sooner or later.

I recently broke a screw on the distributor cap of the Dodge..........couldn't get it out and then broke the mounting ear on the distributor (aluminum) trying to extract the remaining stud.

Now, I await a replacement distributor for it.


These vehicles can challenge the best laid plans from any of us.

u r totally right...I'm stuck in that "gas" fuel injection mentality when trying to visualize the fuel flow out the injector lines...constant high pressure in the fuel rail right up to the actuall injector

__________________
1987 300TDT
1981 VW MKI Caddy 1.6 diesel, waiting on engine swap
1983 D-50 Power Ram 4x4 "Mitsubishi" 2.3 turbo diesel
assorted gas powered crap and motorcycles

RIP: 1984 300TDT, 1982 300TDT, 1984 190D 2.2, 1992 300D 2.5, 1987 300TDT, 1982 Maxima LD28, 1983 Maxima LD28, Isuzu C223 P'ups X3, 1983 Holiday Rambler 6.2 Banks turbo diesel, 1984 Winnebago LeSharo 2.1 TD, 1985 Allegro 6.5

Members FYI:
The rough figure is 0.003 CC per firing of the injector at idle.
= 0.0001014421 ounce.

The (brain busting) fun part is calculating the total delivery valve, injector line, injector volume = how many engine revolutions to expel the air, and achieve stable ignition on all cylinders after major injection system service.


.

__________________
ASE Master Mechanic
https://whunter.carrd.co/

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
2003 Volvo V70

https://www.boldegoist.com/

Hello Odie,
I found your thread and hopefully my experiance from five minutes ago wil be helpful to others that are having a similar problem.

I am fortunate to have Tony the Mercedes fixer here in Eugene. The guy is sincere,meticulas and everything I could hope for as a backstop for my DIY maintenance.

Here is the situation 87 Wagon diesel. Runs PERFECTLY, 1000 miles on complete filters oil maintenance........ My daughter drove it home last night as ussual, this morning it cranks over fine but no start. I found no fuel at the injector but plenty at the lift pump.

Tony's first question was about the stop lever position. It was sitting close to horizontal (3/4" from full off) instead of upright (fuel on). Tony had me disconect the vacuum line and it snapped upright. Car starts right up and continues to run smoothly! (We do need to use the stop lever to turn off the car with the vacuum removed to turn the engine off).

The next step will be to replace the fuel shut off valve.
Does anyone have a repair procedure for teh shut off valve?

Hopefully this note will get someone rolling again.

Best regards,
Nolan