78 240d no start!
 

My 78' 240d is a no start. Here are the things I have done so far:

Changed pre fuel filter and main filter
checked pop pressure and pattern on injectors (perfect with no leaks)
Upgraded to pencil glow plugs and all of them function properly with bypass solenoid
All air is bled out of fuel system
have upgraded the manual primer pump

I have not cleaned in tank screen and don't think this is a problem since when I push the manual primer, I get PLENTY of fuel

I have not rebuilt or replaced lift pump

I just adjusted the fuel pressure relief valve spring, but car is not around and I haven't tried it again. It was maybe close to 3/4 of the 1.24" (somewhere around there) stock length.

When cranking, it does not seem like the injectors are firing at all as there is no smoke or unburned diesel coming out of the exhaust like usually when cold before it starts. Also, it doesn't even TRY to fire. One day it ran fine like usual, then the next day nothing.

Could a bad lift pump make it not get enough fuel to the IP in order not to build enough pressure to pop off injectors? I know some vehicles will still run with a bad lift pump, but I don't know about the 240d.

I also removed the vacuum from the back of the injector pump to make sure there wasn't vacuum there stopping the fuel

have you tried using an auxiliary fuel source and putting it higher than the injection pump so that it gravity feeds into the pump? and when you do that check to make sure fuel comes out of the return line when you are pumping the manual primer pump. another thing is take off the injector hard lines and crank the engine over by hand and make sure the pump is squirting nicely at the injection pump.. it should be a huge squirt that hits the hood... so make sure to be out of the way..

I have not done this yet. Is this a good test for performance of the lift pump?

Thanks

Have you tried loosening a fitting on the injector feed pipes to see if fuel comes out when you crank the engine?
Are you certain the glow plugs are working?

I did loosen the injector lines while cranking at the injectors. A small amount comes out, but the last time I put the new injectors in and bled it, I thought I remembered MUCH more coming out than now. just kind of barely dribbles out.

I am positive the glow plugs are working. I checked to make sure they were getting 12 volts as well as took them out and plugged them up via jumper cables and every one was glowing red at the point.

The usual problem with any engine failing to start is a lack of fuel or ignition.

Did you do all of the work after it failed to start or did you do some of it before? If you did it before, then what did you do last before it failed to start?

Is there plenty of fuel in the tank and is it good fuel (no water in it)?

I ran my car out of fuel once and had a devil of a time getting it going again as I did not realize it was out. I changed glow plugs etc and it still would not fire. I finally poured a 5 gallon can of fuel into the tank and it fired up with only a little bit of cranking.

It has ran fine for the past 3 years I have owned it. Parked it one day recently and the next day is when the no start problem began. The valves were adjusted in the past year.

I have thought about the water in the fuel possibility since I live in West TX currently and the days can go from 20 degrees at night up to 70 during the day at times. (wonder about the tank sweating) There is not much humidity most of the time though. The tank is about half full and I have not added any to it during this problem.

When I get back, I plan on supplying the fuel from a can or jug to see if that changes anything.

Alright, been out of town and busy lately but finally got some time to tinker with the old girl.

I hooked into an external diesel supply to the inlet of the lift pump and bleed the whole system. The 5 gal can of fuel was above the engine. Although it almost seemed like it kiiinnda wanted to try and start, it wouldn't.

I took off the hard lines from the IP to the injectors and turned over. Seems like barely any fuel is pumping from the IP. Almost just like a few measly drops are popping out. I expected much more.

If the lift pump is bad, would it be able to start at all? I also removed the line from the lift pump where it goes to the main fuel filter to see what kind of volume it was putting out. It was between a teaspoon and tablespoon per spurt. I started another thread about what kind of volume I should be seeing here but never got any replies.

Put a new lift pump on and that did the trick. It LIVES

Congratulations on an easy fix.