Does the fuel pump (not the injection nor the manual priming pump) die a slow death i.e. intermittent failure to work properly ranging from working fine for a while to causing rough idling/ rough running/loss of power/ to stalling out? Or is it either all good or sudden complete death - supplies no fuel at all ever again?

Or what symptoms did you experience which were cured by replacing/rebuilding the pump?

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'83 SD, 2x '85 SD
You are entitled to your own opinions, you are not entitled to your own facts.

If you speak of the lift pump I think it just gradually declines.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

As stated it normally gradually declines assuming clean water Diesel Fuel is being used.

The Vlave and little O-ring are replaceable.

Dirt/Rust btween the Piston and the Pump Housing can casue it to stick in one position. That can be sudden.

If a lot of Water Sits in the Fuel Supply/Lift Pump it can cause rust in the Piston Bore and on the Piston. The Piston moves one time and gets stuck.

A broken Piston Returun Spring can cause a sudden failure.

This is extremely rare but I have see at least 2 Push Rods crack.

I have also seen dirt score up the Piston and the Push Rod.

On the whole they are extremly durable and reliable when pumping Diesel Fuel.

Some of the other types of Fuel Injection Pumps use gear Pumps. I don't think a Gear Pump would last for 30 Years of use pumping Diesel Fuel.

The Van type Fuel Supply Pumps (built into the Fuel Injection Pump) on the Roosamaster/Standyne Fuel Injection pumps and the Similar CAV Fuel Injection Pumps and are extremely reliable but do wear a lot compared to the Bosch Lift Pump.

Diaphram Fuel Supply/Lift Pumps work fine but eventually the Diaphram leaks. Simms Fuel Injection Pumps; often seen on Ford Tractors use them as does some of the Catipillar Fuel Injection Pumps. I am not sure what the life span on one is but I think somwhere with in 4+ years the diaphragm would be shot.

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84 300D, 82 Volvo 244Gl Diesel

Pump symptoms would be lack of suction, pressure and or volume.

The Engine Symptoms would be similar to Fuel starvation. But, People have noted it genreally shows up at idle or the low end and might not be noticed at higher speeds. That is the opposite of what plugged/restricted Fuel filter would do.
But, the above would be if it was worn out. Slower Speeds allow the Fuel more time to leak by a worn scored Piston or leaking Valves. Higher speeds don't allow as much time for the leak by to occur.

If a Piston Stuck or or the Piston Spring broke you ought to have Fuel stavation at all speeds.

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84 300D, 82 Volvo 244Gl Diesel

I have had about 20 Mercedes diesels, most with over 200K and a couple over 300K miles and have never replaced a lift pump.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Has the motor been run on vegetable oil (WVO, SVO) or a blend thereof?

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Mac
2002 e320 4matic estate│1985 300d│1980 300td
Previous: 1979 & 1982 & 1983 300sd │ 1982 240d

“Let's take a drive into the middle of nowhere with a packet of Marlboro lights and talk about our lives.” ― Joseph Heller, Catch-22

I recently cleaned up the lift pump in my '80 300TD (448,000 miles). Since the car was given to me at 390,000 needing a transmission, I've been using a blend of WVO and #2 diesel oil. The lift pump piston was stuck tight. I drove it out, cleaned up everything and checked the check valves, and we're back on the road.

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1980 300 TD

1997 Dodge Pickup/Cummins 5.9 12-valve

Steve, good to see you posting. Merry Christmas.

I have been noticing the 240 doing a slight surging when accelerating. very slight, but there. been thinking maybe the lift pump is getting tired, with 360K on it. This might be the starting symptoms of a tired pump.

I have a rebuild kit and a couple spare 617.952 lift pumps to go through the spiffy up. Maybe this is all she needs.

Charlie

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works