1975 240d - No fuel at injectors 1 and 2 - PeachParts Mercedes-Benz Forum

ahawks9er · #1 07-09-2011, 06:28 PM

Hey all! Long time lurker, first time poster. Here's my dilemma:
Car ran great until running out of fuel after developing a hole in tank-to-lift pump supply line.
Replaced damaged line and inline filter.
Replaced injector return lines while I was under the hood.
Primed system with Monark HD priming pump (newish.)
Attempted to purge inj. lines by cracking the inj. nuts as I have done before. I got fuel out of injectors 3 and 4, but not out of 1 and 2. The car will not run on the back two cylinders alone and after much cranking, I decided to adjust the return fuel check valve spring to 27mm after reading somewhere that this could help with a weak lift pump.
Still no fuel at injectors 1&2. After four hours of cranking, I'm about out of ideas so I'm hitting the forums! Any help is appreciated.

I am considering:
Tank screen
Weak lift pump
Stuck delivery valves
Setting up a temp. fuel tank (like when doing diesel purge) in an attempt to remove any tank supply problems.
Fogging the intake with WD40 to try to "run through the air" in the system (if thats the problem)

-=DeanstuD=- · #2 07-09-2011, 06:33 PM

I don't have your answer, but welcome another Portlander.

ahawks9er · #3 07-09-2011, 06:52 PM

Thank, bud. I wish I was here posting under better circumstances.

I've also considered pulling the glow plugs to let it crank over easier and just keeping... on... cranking. I really don't want to kill my starter if the problem is something else.

I think I have a 1980 300d I could steal the lift pump off of if they are interchangable, but it doesn't look like a fun job.

-=DeanstuD=- · #4 07-09-2011, 07:50 PM

There are so many people who know better than me..... I would say you haven't primed the system though you say you have. "I" would take of my spin on filter and make sure it was full of fuel, then I would crack the to lines you haven't seen fuel from and pump the primer pump until I saw fuel. I then would tighten them down and hold my foot to the floor and crank the starter until it runs and runs well.

I have never done the old engines with the hand pump. I only have changed lines and filters on the 603 that has no pump.

I know you have probably already done all this, but I would do it again and again until I saw the fuel at the lines you haven't seen it at. "I" certainly wouldn't go to all the trouble of swapping out a lift pump. Certainly not yet.

I think you spin on filter isn't full, and I think it will take 2.7 million pumps of the plunger to fill it.

ahawks9er · #5 07-09-2011, 08:00 PM

Ya know, that's fair. Maybe I only pumped 2.6M times

I have a canister filter instead of a spin on, but the principle is the same. I guess I should make absolutely sure that I'm getting fuel out the return side, but I thought I was. I'm mostly struck by having fuel in only half my injectors, but maybe there's not much in those two either.