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1979 Mercedes Engine Dies - What could be the problem?

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  #11  
Old 02-13-2007, 12:11 PM
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Default RE: 1979 Mercedes Engine Dies - What could be the problem?

As I understand it, the injector pump rarely conks out, but it's mechanical so of course it does occasionally belly up.You might tryloosening the fuel injector lines at the top of the fuel injectors and havesomeone crank the engine while you check for a healthy fuel flow. But I don't know how to check for the needed pressure... For all I know, even though you're getting what seems to be enough fuel from your tank and throughyour fuel filter, it maynot be enough to feed the engine.There still may not be enough fuel pressure there to the IP to keep the engine running and, even though it gravity flows, it could still be partially blocked. The only true way to test that is by switching those incoming and outgoing fuel lines as I discribed in the first post. If you haven't done that, then, IMHO, you haven't yet eliminated that problem...

Theres a couple of very smart mechanics on this forum, such as forcedinduction, who might know how to test the IP. If not, there's adozen or moreof really smart MB diesel mechanics at some old man That's where I go when I really need help.Henry Schuman, who has been aMB dieselmechanic for decades, willeven get you the best prices on new and used MB parts. Or others there may be willing to trade parts, etc.... In my book, some of those guys are genuis'es at tinkering....
 

Last edited by ForcedInduction; 07-26-2011 at 11:38 PM.
  #12  
Old 02-13-2007, 12:20 PM
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Default RE: 1979 Mercedes Engine Dies - What could be the problem?

Charles,
Thanks for the tips. I will try that again. I had replaced the fuel filters but will try that again. What is still is wierd is this
Why would you get diesel spray/mist coming out of the exaust pipe, when I KNOW the glow plugs are working.
ALSO, the engine isn't cranking as easy as it use to. I had put a new battery in it and same thing. It is like something is restrictingthe engine down. Hopefully the compression check shows everything ok. I am afraid of a blown head gasket. I don't know what else it could be.

Do you know ifairenters theInjector pump. If so, is there a flap or something that would stop the air from mixing with the fuel. I think the fuel just gets sprayed into the injector with no air. Just not sure what the vacuum hoses are going to on top of the injector. Do you know.
 
  #13  
Old 02-13-2007, 12:27 PM
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Default RE: 1979 Mercedes Engine Dies - What could be the problem?

Maybe a broken or burnt piston? But probably not. It seems to me that it's usually something simple... Believe me, if those guys at some old man can't come up with some answers, no one can....
 

Last edited by ForcedInduction; 07-26-2011 at 11:38 PM.
  #14  
Old 02-13-2007, 12:40 PM
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Default RE: 1979 Mercedes Engine Dies - What could be the problem?

BTW, did you also replace the heat shields when you replaced the injectors? And were they put in with the right side up? Is it leaking fuel at the base of the injectors? Also, since you smelled raw diesel at the tail pipe it sounds like it's not firing... so I can see why you ordered the compression set....I don't remember if you tested the glow plugs....But since the engine is hard to crank... it's probably not a broken piston top....Maybe it still could be a burn't piston.... dieselgiant.com has a picture of a burnt piston in an old MB engine here: http://www.dieselgiant.com/mercedes6...einternals.htm
 
  #15  
Old 02-13-2007, 12:47 PM
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Default RE: 1979 Mercedes Engine Dies - What could be the problem?

diesel fumes coming out of the exhaust pipe
Unburnt fuel may be the effect of a burnt piston. Still leaning towards bad glow plugs as well. When was the last time those have been changed?
 
  #16  
Old 02-13-2007, 01:20 PM
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Default RE: 1979 Mercedes Engine Dies - What could be the problem?

ORIGINAL: sfk

ALSO, the engine isn't cranking as easy as it use to. I had put a new battery in it and same thing. It is like something is restrictingthe engine down.
A common problem is a corroded ground connection on the starter... In fact you need to go through all of the ground connections, from the battery to the relays, to the starter....

Do you know ifairenters theInjector pump. If so, is there a flap or something that would stop the air from mixing with the fuel. I think the fuel just gets sprayed into the injector with no air. Just not sure what the vacuum hoses are going to on top of the injector. Do you know.
I can't see how those lines have anything to do with your problem/problems...That's for the vacuum engine cutoff. dieselgiant.com has a pictorial about that.... it's great... shows how to remove all vacuum lines, and brake line around the ALDA and then remove the ALDA so you can look into the pump in order to see how to connect the vacuum engine cutoff switch...
 
  #17  
Old 07-10-2007, 07:45 PM
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Default RE: 1979 Mercedes Engine Dies - What could be the problem?

check your engine harness as well..
 
  #18  
Old 01-08-2008, 07:06 AM
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Default RE: 1979 Mercedes Engine Dies - What could be the problem?

I am the one who posted this Question.

I took the engine apart and #2 piston rings were shot. (I could move the piston slightly with one had. I'll try to post a photo. Thanks for your help.
 
  #19  
Old 01-10-2008, 09:32 PM
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Default RE: 1979 Mercedes Engine Dies - What could be the problem?

Just as a final follow up in case anyone else has this problems

It turned out to be the #2 cyclinder. The rings broke, so when I took the head off, you could move the piston back and forth a little. I am now swapping engines.
Thanks for your help
 
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