Greetings!

I have a 78 240D that I bought from the executor of the original owner’s estate. It has 205k on it and I bought it for $1,000, running. However, it had been sitting for eight years, so it needed new brakes all around and a new set of tires. I’ve put about 1,000 miles on it so far and really enjoy it. After a recent 120 drive, I pulled it into my “ghetto barn” (Costco tent garage) to change the alternator belt. When I was done, I attempted to start it up, with no joy. I thought I might have air in the injector tubes (that had happed recently after a valve adjustment), so I loosened the injector caps at the injectors and turned the car over. Nothing, just a slight weeping of diesel out of the #3 and #4 caps. The next day I checked the primary fuel filter. Clogged solid. After replacing it I tried again. Nothing. Today I changed the secondary fuel filter and primed it good. Still no change. So I did the following:
1. I removed the secondary fuel filter and put a catch cup under it. I then pumped the primer pump and fuel came out of the filter housing just fine.
2. Replaced the filter and disconnected the banjo fitting from the big injection unit. Pumped the primer. Plenty of fuel came out. With the banjo fitting still off, I cleaned out the catch cup, screwed in the primer pump, and then tried starting the car. Not a drop of fuel came out of the banjo fitting. At this point I started suspecting a bad fuel pump diaphragm. Later however, I had the misses try to start the car over while I pumped away at the primer pump, hoping to manually pressurize the fuel line and get some type of ignition. Nothing. I even loosened the injector caps again and had her turn the car over while I pumped the primer. Nothing. No fuel coming out of any of the injectors.
3. One last bit of information: the primer pump leaks like a sieve when I’m pumping it. Not so bad with the filter off or the banjo connector disconnected, but with the both of them on, lots of diesel squirting out!
I would greatly appreciate any help I can get from the forum members to get this resolved. I’m hoping it’s just the fuel pump and not the injector unit. I’m pretty good with a wrench; I did all the brakes and the valve job already. I look forward to your replies.
Many thanks!

 

If the primer pump is leaking, then the first thing to do would be to repair that leak. Any leaks anywhere will cause it to either run rough, or not at all. Air in the fuel system is public enemy #1