PEH:

The hand pump, I think, is under pressure all the time. If the piston seals go, usually when it is used after being screwed down for a long time, it leaks. Could have started when the fuel filters were changed, and leaked enough to get substantial air into the IP as it was driven.

The old 220D did exactly that -- it was hard to start anyway (low compression), but with bad fuel lines and a bad hand pump, would run if you got it going, but would be nearly impossible to start the next day.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Psfred,

I think the hand pump is under suction when screwed shut and the main pump is drawing fuel thru the hand pump because it is closer to the fuel tank than the main fuel pump. So if the hand pump leaks, air could be sucked in when the main fuel pump is drawing fuel thru the hand pump. I thought once the knob was screwed down that it sealed the hand pump, but I suppose that seal could leak too. I have had hand pumps that leaked when they were manually pumped but they still pumped fuel and didn't affect operation of the engine once the handle was screwed shut.

I wonder why MB left the hand pump off the newer 6 cylinder Diesel engines. I ran my 6 cylinder out of fuel once and it started without doing anything but adding fuel but I had to crank the engine for quite a while. I would rather have pumped a hand pump than put all that strain on the starter.

P E H

PEH:

I know what you mean. I intend to change the fuel filters on the E300D with the engine hot, and to fill the main filter when I install it. I have now idea why the left the hand pump off, except maybe they figured the newer lift pump would work fast enough to make it unnecessary. It is entirely possible to run the battery flat before the car starts with a fuel line leak, let alone an empty fuel filter!

You're right, the hand pump is under suction whilst the lift pump is operating. The new style pump is sealed, much better.

baporter:

If you are still seeing air bubbles in the clear lines, you have not managed to get the air out. Either the hand pump is leaking air in on the suction stroke (entirely likely) or you have a loose or bad suction line from the tank. Check the suction line carefully -- it will leak back into the tank, not out onto the ground unless the car is parked on a steep hill nose down! The rubber under the fabric braid can be rotten without the fabric showing any deterioration, too.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Psfred,

I looked at the main, actually the only, fuel pump on my 300SDL 6 cylinder yesterday and it different than the pump on the 5 cylinder engines. So maybe thats why no hand pump, the new fuel pump has a high enough capacity to quickly pump enough fuel to prime the engine.

I found out one thing though, the 300SDL wouldn't start after running out of fuel with only one gallon of fuel poured into the fuel tank. It did start after the second gallon was added.

I checked the fuel mileage on the 300SDL yesterday. It got almost 36 MPG on a trip from TX to PA. I won't complain about that. That's as good or better than some of the little piss ant cars get and the 300SDL is a big sedan.

One question: Why are you changing the fuel filters? Are you experiencing a loss of power or do you just think it is time for a change?

P E H

PEH:

I have no idea when they were changed last, and I've put about 4000 miles on since I bought it. The main filter is sort of corroded, and the gasket doesn't look too good, so I figure I will change it next oil change. Should be in the neighborhood of 180,000 miles.

I'm jealous -- I only got 31 mpg or so on the trip to Florida. I've pulled the control line off the air bypass -- maybe I should put it back on, it seems to cut the boost at highway speed with low load and might reduce fuel consumption. I did drive at almost 80 the whole trip, though, to avoid being run over.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Psfred,

If you are not experiencing a loss of power, the fuel filtrs are OK. Usually dirt that gets in the fuel tank gets there at one filling because the source of fuel had dirt in it. Therefore even a new filter can get clogged almost as fast an old filter. This happened to me in Colorado where I plugged 3 filters shortly after a fill up.

I only change the filters when I notice a loss of power or the filter starts to leak thru the metal skin which has happened twice. I always carry extra filters and change them as needed. I keep the old filter, clean it out and use it again. I know others out there wouldn't do this, but it works for me.

P E H

I have not been able to get the car started now since my last post(about 1-1/2 weeks)

I finally broke down and took it to a mech. He told me that the compression in the #1 was 280, #2 180, #3 200, #4 210, and #5 210, with the #2 injector not working.

My question is: Is it worth it to have him do a valve job est. at 400-2000 dependant upon what is wrong or just scrap the car?

The car is sitting at the Mech. shop. Talked to the Mech. again today and he said that the valves were not too loose or too tight. I guess the compression test does not lie. Problem is he wants 1000 to start, because he does not know how much damage there is until he takes it apart. And to see if the valve job would even be worth it. I am weary because he quoted that the job depending on what is wrong with it is between 400-2000. What even gets me more is that he is a very reputable Mech.

I would figure that he would do the leak test.

Any advice?

I have a similar problem and would like to know how to do a compression check?

Thanks, Goodmite