Mercedes-Benz Forum banner

injector pump recomendations?

1082 Views 3 Replies 3 Participants Last post by  Scheissmeisser
I picked up my ebay 300DT. It turned out to be a bit of a beater. Hit hard once on the left side fixed by earl shieb. Put 300 miles on it right away got 31 mpg!( a little too good to be true) Ran ok out on the highway exept for a balance and alignement problem.
Car was unbelievably gutless of the line. When got home on the sugestion of a buddy who knows these cars I adjusted the alda valve out some. Made a big difference in off the line performance. I adjusted it all the way out to the stop and still no black smoke. When I told him I'd gone out to the stop he said the injector pump is probably wore out. He recomended a guy in ca. to overhaul it. But for $800.00 ouch! Is there a less expensive route? The car is running real good right now. What harm will I do continuing to run it on the lean side if I dont run it real hard?
Not open for further replies.
1 - 4 of 4 Posts
Well, I'm somewhat new to diesels (but not to turbos), but it is my understanding that the...

Well, I'm somewhat new to diesels (but not to turbos), but it is my understanding that there is no such thing as a "lean" condition in a turbodiesel, at least where it will cause a problem. Since the fuel is injected at the point in the compression stroke where you are past the point where detonation is a problem (you don't ever compress a fuel mixture before ignition), you can run them "lean" and you will just experience a drop in power.

So I would say you are probably ok to run it as is.
lean conditions

Thanks I did'nt know that about turbo diesels. I've just seen where on turbocharged gasoline continental aircraft engines can melt a piston with a faulty injector creating a lean condition.
Also I was looking real close today running her down the highway when I get on it I can see just a tiny bit of black smoke. So I can probably back off the mixture a little and figure the injector pump will last a little while longer. [8D]

By design,diesels ALWAYS run on the lean side of a stoichiometric mixture.If your injection pump were actually "worn out",you'd have serious starting and/or driveability issues.Most "injection pump" problems are cured by just changing the fuel filters.
Since,as you said,adjusting the ALDA improved your car's performance,I'd say that that your injection pump is just fine.Short of abuse,MBZ injection pumps last as long as the engines.
FWIW,the $800.00 quote is in the ballpark for a rebuilt injection pump.Plan on an additional charge of several more hours of shop labor to R&R/re-time the pump.[:0]
1 - 4 of 4 Posts
Not open for further replies.