New Owner/Injector pump bad?
 

Hey, I just bought a 1978 240D, which doesn't run. We were told by the mechanic that the injector pump was bad. We put a battery in it and it turned over fine, all the gauges work and the body's in perfect condition, 175k miles, for $800. I got the Hayes manual and it said the pump could only be tested by a professional with all the right equipment, etc. How much does a new pump cost, or would it be better to have the original one rebuilt, and what cost would that be?
I'm looking to run biodiesel in the car after I get it running good, so I assume the either new or rebuilt pump would have seals that would be compatible for the biodiesel, correct?

thanks in advance for the help!

Luke

well
 

if i had a dollar for every mb injection pump that was changed unfairly i would be rich. mb injection pumps are really rugged and seldom go bad. i would get a second opinion before changing one. i have paid for several to be changed myself and it never has fixed the problem being chased....NEVER.

so i say do the basics... change fuel filters both. air filter. add fuel injector cleaner and fungicide to the fuel let it sit over night and try the next day. if it doesnt start try pulling it.

the last thing i would suspect is the ip.... the last.

tom w

Check the archives or your Haynes manual for how to prime the IP. Check also simpler things like a bad key switch causing the stop lever to stay down, a bad fuel pump on the side of the IP, etc.

Sixto
95 S420
87 300SDL

I know absolutely nothing about these diesel mercedes, I'm used to working on a big block Plymouth Valiant. How is the fuel pump checked, how can you check if the stop lever is staying down.

I'll do the fuel filters, air, and the fuel injector cleaner. Is the fungicide a thing just for diesels, I assume you can get it at a parts store?

Thanks
Luke

fungicide
 

is available at truck and or tractor supply places. yes, diesel only.

tom w

Loosen the big bolt at the center of the big spin-on filter. Move the plunger of the primer pump (either a loop like the dipstick handle or a knurled cover that pops up on it's own when you unscrew it). Fuel should leak out of the loose center bolt. Crank the engine with the starter. Fuel should leak out of the center bolt.

The stop lever is propped up at about a 75* angle when the engine is running. You push the lever down to about level to cut fuel and kill the engine from under the hood. If the lever is down for whatever reason, fuel will not get to the cylinders. It will stay down after you shut off the engine using the key switch until vacuum bleeds from the shut-off valve. When you turn the key to ON, it should instantaneously pop back to near vertical. If it's stuck down as you're cranking, pull it up, hold it that way and start the engine.

Sixto
95 S420
87 300SDL