617 300SD starts/dies...why? - PeachParts Mercedes-Benz Forum

crashone · #1 07-05-2007, 10:04 PM

Here's some back ground--Monday the SD drove fine, no problems. Tuesday the SD started up fine , pulled out of my driveway got 50 feet engine dies, restart, move 15 feet, engine dies. I have to start/restart a couple of times to get back in driveway. Tuesday night I changed both filters thinking maybe something plugged one up, still has the same symtoms. Tonight I hook up a bottle of diesel like I was going to do a purge on it, runs a little then dies, I keep restarting (~4 or 5 times) until it seems like it will only get to an idle and then it dies. So I think I have eliminated clogged filters and a clogged tank screen. Now my questions are - what is going on and what do I need to check next. Thanks.

kerry · #2 07-05-2007, 10:18 PM

Shut off diaphragm malfunctioning? Try unplugging the vacuum line from the shut off and see if the situation improves.

Brian Carlton · #3 07-05-2007, 10:38 PM

Fuel pump on the way out?

See how much fuel you get by cranking for 10 seconds. Run the output of the pump into a container.

crashone · #4 07-05-2007, 10:49 PM

Thanks kerry edwards, I just went out and tried that, nope no change. This seems to have happened overnight, MB diesel grimlins showed up I guess.

crashone · #5 07-05-2007, 10:52 PM

Brian, just saw your post, please elaborate. I will try that tomorrow. I was wondering about the fuel pump, would these be the symtoms?

kerry · #6 07-05-2007, 10:54 PM

Try Brian's suggestion, then try an alternative fuel supply in a coke bottle led directly to the primary filter to eliminate air leaks between tank and filter as the source of the problem.

Brian Carlton · #7 07-05-2007, 10:56 PM

Quote:

Originally Posted by crashone

Brian, just saw your post, please elaborate. I will try that tomorrow. I was wondering about the fuel pump, would these be the symtoms?

Run the output from the fuel pump into a container and crank the engine for 10 seconds. You should get about 2 ounces of fuel. If you don't, the pump is suspect. A proper test for fuel pressure is the only sure confirmation.

crashone · #8 07-05-2007, 10:58 PM

"then try an alternative fuel supply in a coke bottle led directly to the primary filter "

I did this, that's how I eliminated the clogged tank screen part. Yes tomorrow evening I will try Brian's suggestion. Thank you for the help.

crashone · #9 07-05-2007, 11:03 PM

Brian earlier today when I did the bottle of diesel trick (like a purge set up) I thought the out flow seemed weak. I thought the out flow would have a little more force to it.

kerry · #10 07-05-2007, 11:07 PM

Quote:

Originally Posted by crashone

Brian earlier today when I did the bottle of diesel trick (like a purge set up) I thought the out flow seemed weak. I thought the out flow would have a little more force to it.

You should have a very strong flow from the return line into the bottle.

crashone · #11 07-05-2007, 11:11 PM

Ahhh we are getting somewhere!! The flow was very weak, in fact I wondered how people could suck a bottle dry as fast as they have reported. I had a fuel pump go out on my truck that was from one start to the next. Thanks again.

Brian Carlton · #12 07-05-2007, 11:29 PM

Quote:

Originally Posted by crashone

Brian earlier today when I did the bottle of diesel trick (like a purge set up) I thought the out flow seemed weak. I thought the out flow would have a little more force to it.

Test the fuel pump as I advised above. Report back.

mbbilbao · #13 07-06-2007, 01:05 PM

primer pump might be leaking and air is suck in instead of fuel

crashone · #14 07-06-2007, 09:34 PM

Well I guess a teaspoon or so doesn't add up to a couple of ounces after 10 seconds or so. I went ahead and pulled the fuel pump. I think might go snag one tomorrow at the boneyard so I can be sure before spending the big bucks on a new pump. Is there any way to rebuild one of these? Thanks.

Brian Carlton · #15 07-06-2007, 11:04 PM

Quote:

Originally Posted by crashone

Well I guess a teaspoon or so doesn't add up to a couple of ounces after 10 seconds or so. I went ahead and pulled the fuel pump. I think might go snag one tomorrow at the boneyard so I can be sure before spending the big bucks on a new pump. Is there any way to rebuild one of these? Thanks.

Yep, a teaspoon won't keep that engine running. A new pump should solve the problem.

Not sure on a rebuild..........haven't heard of anyone doing that..........