2007 sprinter quitting

I own a 07 2500 with about 270k. Unit works great from Monday to Saturday,
Off Sunday. Come Monday morning the van starts but the idle surges between
800 to 950ish. The idle will either clear up or stall. If it stalls the only way to start
Is to remove the fuel line from the filter under the air cleaner. No key on just simple remove and and reinstall, fires up and drives. This issue only occurs when the temperature is cold, no issues in the summer. It's been to dealers and private mechanics but no better, anybody ever run across this issue? Any info would be greatly appreciated.

nelson,
Have you had the pressure output from the lift pump in your fuel tank checked.
Could be the lift pump isn't pushing enough fuel pressure to the high pressure pump to trip
the low fuel pressure sensor.
Or somehow when you loosen the lines to the fuel filter it clears something between the lift
pump and high pressure pump.
Might also have Mercedes Dealer hook you up to the MB SDS system and read your cold start fuel
raail pressure.
Roger

I haven't personal checked the tank pump pressure but I asked the dealer if they checked and they said it checked good. I suspect I will need to check it in the morning after it has been sitting for a day. Do we now what the pressure should be at?

This is a verbatim quote from the service manual CD for 2007 US/Canadian Diesel Sprinters.



-Jon

Will check tomorrow, thanks

Couple things...which fuel line on the filter are you taking off...or does it matter?

Next time it stalls...remove the fuel tank cap, instead of the fuel line, for a minute and see if that lets it start.

I will be checking the fuel pressure today, I also will try the gas cap. Either fuel line works? I was thinking maybe its not the fuel line that I'm removing but maybe it some electrical connection that disconnecting and reconnecting when your removing the air box and engine cover. I will spend some time today disconnecting and reconnecting one thing at a time and see if its not something else.

nelson said:

I will be checking the fuel pressure today, I also will try the gas cap. Either fuel line works? I was thinking maybe its not the fuel line that I'm removing but maybe it some electrical connection that disconnecting and reconnecting when your removing the air box and engine cover. I will spend some time today disconnecting and reconnecting one thing at a time and see if its not something else.

Click to expand...

That's a good plan. Remember to use a "T" fitting when you're checking the fuel supply line pressure to the filter. You'll get a false reading if you just block off the fuel supply line with a pressure gauge.

If the filter's not new, or if you suspect you may have picked up some less-than-fresh diesel fuel, if you suspect marginal contamination of fuel in the tank, you might want to check the pre- and post-fuel filter pressure, aka the pressure differential.

Again, from the service manual:

14 Fuel System -> Fuel Filter


-Jon