Pinging diesel

[downunderdave]

Originally Posted by Farwest

Little bit of related info from a google search on OM642 Mercedes Benz Diesel Engines at a Site/Forum by autospruce.com....lists a few issues you have noted in this thread...BUT...you seem to have covered them ???
Merc pumps are EXTREMELY finnicky things...a tiny mix of water and a doide in the pump 'smashes' sending engine into limp mode...diode is internal of pump and a 'shield'(was how my Merc Man explained it) protecting the diode is designed to 'shatter/break' when water is present in pump...not talking about the fuel pump...I mean the actual internals of the Fuel Injection Pump...may have NO bearing on what your experiencing...but...symptoms are the same...NOW....replacing the Pump is ULTRA expensive...however...a GOOD Diesel Engineering Shop CAN pull the pump to pieces..replace the diode and 'shield'...in effect rebiulding the pump...for a fraction of the cost...my suggestion...find the best Mercedes TRUCK Mechanics shop and approach them...this is a COMMON fault...MAY NOT be whats wrong with yours...only passing on what Ive learnt from experience with Merc Diesels..GOOD LUCK.....HOPING its not your problem to be honest...freakkin EXXY !!!!

ps: after 'cactusing' 2x pumps...I fitted Dephi inline Water Seperators to every Benz I had and fitted them to EVERY new Benz I bought prior leaving the Dealership..WAS a Fleet Buyer...the Delphi added an extra inline Filter, which cant hurt, and didnt effect the 'draw power' from the tank...only speaking from experience...NOT Mechanical knowledge...which I have a little of...but am smart enough to know I know nothing

Thanks greatly for this info. My mechanic did find water in the diesel, so I'm now worried about the pump diode. Really appreciate the info.

[Clarky]

Now I'm not trying to dismiss this post but I have removed my HP pump from my OM642 (06 and 09 model) and it has no electrical connection to anything, it is purely mechanical. Not saying other vehicle's with the OM642 engine don't have a different HP pump setup but the Jeep is not one of them.

One problem the pumps do have is the screws holding the pump housing together can vibrate loose allowing then to separate and leak diesel. You have to pull the pump off the block to do them back up, that's how I know there is no electrical connection.
And for added info the HP pump is not timed to the engine so you can't put it back on wrong.

Now if this is referring to the fuel supply pump from the fuel tank then I have no idea as I have never touched it.

Originally Posted by Farwest

Little bit of related info from a google search on OM642 Mercedes Benz Diesel Engines at a Site/Forum by autospruce.com....lists a few issues you have noted in this thread...BUT...you seem to have covered them ???
Merc pumps are EXTREMELY finnicky things...a tiny mix of water and a doide in the pump 'smashes' sending engine into limp mode...diode is internal of pump and a 'shield'(was how my Merc Man explained it) protecting the diode is designed to 'shatter/break' when water is present in pump...not talking about the fuel pump...I mean the actual internals of the Fuel Injection Pump...may have NO bearing on what your experiencing...but...symptoms are the same...NOW....replacing the Pump is ULTRA expensive...however...a GOOD Diesel Engineering Shop CAN pull the pump to pieces..replace the diode and 'shield'...in effect rebiulding the pump...for a fraction of the cost...my suggestion...find the best Mercedes TRUCK Mechanics shop and approach them...this is a COMMON fault...MAY NOT be whats wrong with yours...only passing on what Ive learnt from experience with Merc Diesels..GOOD LUCK.....HOPING its not your problem to be honest...freakkin EXXY !!!!

ps: after 'cactusing' 2x pumps...I fitted Dephi inline Water Seperators to every Benz I had and fitted them to EVERY new Benz I bought prior leaving the Dealership..WAS a Fleet Buyer...the Delphi added an extra inline Filter, which cant hurt, and didnt effect the 'draw power' from the tank...only speaking from experience...NOT Mechanical knowledge...which I have a little of...but am smart enough to know I know nothing

[Clarky]

No need to apologies my fellow Jeep addict.
The point of the forum is to discuss and help each other out. My knowledge has only come about through trial and error and lots and lots of hours scrolling through various forums looking for answers. We don't always get good info from the interweb.
Back when I began my Jeep journey I was forever mixing up all the info in my head, confusing swirl motors with turbo actuators etc.
It's a Jeep thing

Originally Posted by Farwest

As I said...not from Mechanical knowledge from experience...pumps were on Benz Sprinter Vans...I imported them for a purpose similiar to Dueschte(German) Post...up and down freeways constantly...I couldnt see...or find...anything like what my Benz Man was talking about...no wiring...no electrics...the engines I had may not have even been whats being discussed....they were 5cyl turbo...4cyl turbo engines...I do not know what 'engine model/type they were...my apologies for adding material that may not be relevant...its the wisdom from members here that helps me

[downunderdave]

My ongoing thanks guys. My Jeep still is with the mechanic. He is a good friend of mine, so he is working on other cars as well. Still stumped about the isue though. Any further ideas greatly appreciated, and when, well hopefully when, the isuue is resolved I'll post it here. Many thanks, Dave.