Is it leaking or drinking??? - PeachParts Mercedes-Benz Forum

Actros617 · #1 09-04-2008, 03:50 PM

Recentely I was filling up 2.5 gal and going on 27 round trip (highway driving @ 60 MPH), and every time i return home it would sit slighty above where it was sitting before i fill up my tank with 2.5 gallon, so i am think i am getting around say....hmmm 13 MPG

I have a lot of smoke no matter how low i adjust my ADLA so that's not the problem, so i am thinking it must be leaking somewhere i dont smell diesel but is there places when it will leak only when driving, or is my injector is OVER feeding my engine, Heck i can even see my gas needle MOVE VERY slowly going on the high way at 60 mpg, the gas needle HAUL @$$ to R at 90 mph

.... Also out of all OM617 Turbodiesel i ever driven (W123 and W126) this one flys like a rocket, I can beat my dad's 300SDL (and the 300SDL engine and drivetrain is very well taken car of) Anyways suggestion????

babymog · #2 09-04-2008, 04:43 PM

I would find out what's wrong with Dad's '87, sounds like a pig if the '84 beats it.

Lots of fuel, check timing, injectors, valve adjust, brakes dragging, alignment, air filter and intake problems, and finally injection pump if all else fails. Lots of things can cause bad mileage including a lead-foot.

bustedbenz · #3 09-04-2008, 04:49 PM

Quote:

Originally Posted by Actros617

Recentely I was filling up 2.5 gal and going on 27 round trip (highway driving @ 60 MPH), and every time i return home it would sit slighty above where it was sitting before i fill up my tank with 2.5 gallon, so i am think i am getting around say....hmmm 13 MPG

I have a lot of smoke no matter how low i adjust my ADLA so that's not the problem, so i am thinking it must be leaking somewhere i dont smell diesel but is there places when it will leak only when driving, or is my injector is OVER feeding my engine, Heck i can even see my gas needle MOVE VERY slowly going on the high way at 60 mpg, the gas needle HAUL @$$ to R at 90 mph

.... Also out of all OM617 Turbodiesel i ever driven (W123 and W126) this one flys like a rocket, I can beat my dad's 300SDL (and the 300SDL engine and drivetrain is very well taken car of) Anyways suggestion????

I'm going to just point out the first possible problem here before we even get too far into the technicals of the engine - watching the fuel gauge is by no means an accurate measure of what is happening for fuel economy.

These gauges are rather notoriously inaccurate. I don't think it's even physically possible for an injector to push enough fuel through the engine, 90 mph or no, to perceive the needle moving as dramatically as you describe.

The first thing we need before we even start diagnosing fuel system problems is a good baseline of your mileage. Pull up to the levelest diesel pump you can find, and carefully fill the tank right up until the fuel is ready to spill out of the filler neck. This way, you can fill consistently each time.

Now drive 200 or 250 or 300 miles or however far you feel safe running it if you really do suspect a leak that rapid - maybe take a clean (as in, dust-free) yardstick and stick it down in your tank to verify that there is still fuel in there, if you get nervous - and then fill up again, at the same pump, to the same level. Divide the number of miles you went (according to the odometer or a gps) by the number of gallons it consumed, and tell us the number.

winmutt · #4 09-04-2008, 05:45 PM

Pop test the injectors. If you have one stuck open in can certainly cause lots of smoke and poor economy. Also verify you IP timing.

pawoSD · #5 09-04-2008, 06:23 PM

I second the test on the injectors.....if one is dumping fuel you're looking at bad things happening to the engine.....

Actros617 · #6 09-04-2008, 07:06 PM

The 300SDL is in great condition it runs just fine it has lots of pick up enough to tuck you into the seat, anyways i am going to do a pop test soon if i have time in my hand, as far as maintance is all up to date Valve adjustment is done, all filters changed oil chaged 2 months ago trany 2 1/2 months ago no leak in the the engine bay but may perisit somewhere, Unfortunatly my odometer is broke i just look at where it was and google map my every day destination 2X and got 26 and attempt take a pic of where it was and compari...