Actually for 19.8 gallons.

Seems pretty low to me, even for city driving.

I typically have gotten around 400 miles to a tankful for city and 600/hwy.

The car is running fine and there are no leaks, so I will chalk it up to bad fuel and monitor my driving habits closer, as I have been flooring it all the time for the hell of it.

I also filled up at a truck stop, hoping for more quality fuel.

Any thoughts? I use redline routinely and there is no nailing or injector knock to speak of, giving me no indication of any injector problems so I am a bit befuddled.

It does miss periodically at idle and I will be running some diesel purge as soon as the UPS guy gets it here.

Thanks

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Enough about me, how are you doing?

Most I got out of that car was 420/430 miles per tank. Normal was ~350. I think I got 500 once.

I got 600 per tank on the way down here from Jersey. Have almost always gotten 400 in city per tankful.

This last tankful yielded an average of 18.3 miles per gallon, which is no where near the 25-30 others have posted.

18.3 is not bad, but I sort of was expecting in the 25 mpg range.

We'll see if the purge improves economy any, if not I will go ahead and get the injectors replaced.

Thanks

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Enough about me, how are you doing?

Stumbling idle can also be valve adjust..... and if valves have tightened up (gaps have narrowed) it makes sense you are losing engine efficiency.

Another culprit might be injector pump timing - does the engine blow alot of unburnt fuel??

Does this particular engine(603?) have any particular way to check the valves? Or is it best done by an indy?

Thanks

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Enough about me, how are you doing?

It's a throttle, not an on/off switch !

These are opposing concepts..."flooring it all the time" and concern about mileage.

If you want mileage, start by driving like it...if you want performance, get a muscle car.

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Diesel-guy

Are you certain that the odometer/trip odo aren't slipping, giving you a falsely low mileage reading?

Even with me flooring it all the time and with two fuel leaks (fuel leaks fixed and foot fixed by discovering a bypassed boost fuel control valve one of these leaks was brief, but it was one of the fuel return lines popping off the injector), I've never gotten below 22mpg...granted, I've got a smaller car, but I've always been under the impression that the OM603 is more efficient than the OM617...?

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2001 VW Jetta TDI, 5 speed, daily driver
1991 Ford F-350, work in progress
1984 Ford F-250 4x4, 6.9l turbo diesel, 5 speed manual
Previous oilburners: 1980 IH Scout, 1984 E-350, 1985 M-B 300D, 1979 M-B 300SD, 1983 M-B 300D
Spark-free since 1999

and if you want a throttle get a gasser - diesels don't have them

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1982 Mercedes-Benz 300CD
1982 Mercedes-Benz 240D - stick

Valve adjustments are not rquired on the 603 engines. That went away with the 617 eng. Speed definetly affects fuel economy. In my '87TD (603 eng.), driving between 75-80 I only get 26 mpg highway. However when I have been caught up in traffic and forced to travel at a slower rate, I definetly see a difference. Traveling at the forementioned speed I would go about 115 miles per quarter tank. When I got caught up in that slower traffic, I noticed that I had gone 190 miles had only used up 1/3 of a tank.

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1999 MB SL500 (110,000 mi)
2004 Volvo V70 2.5T (220,000 mi)
2014 Tesla Model S 85 (136,000 mi)
MBCA member

fuel does make a difference. on a lengthy highway run from ct-fla last year i noticed quite a bit of fluctuation in mileage achieved and different fuel sources. all the time the speed/weather conditions were consistent.
up here i get better mileage from a hess station i go to as opposed to citgo. go figure.

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1984 300D Turbo - 231k....totalled 11/30/07 RIP

Haynes, Diesel 123 series manual, pg. 47 , section 18 - "THROTTLE linkage check and lubrication". etc.

MBZ Factory Service Manual, Engine 617.95 at 30-300 - "Adjusting throttle linkage"

I could have used the term "accelerator pedal", but it is still connected to the "Throttle linkage". How about "speed controlling device" or "Diesel fuel metering device" ?

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Diesel-guy

18.3 miles per gallon is still pretty good for a car this large/heavy.

If this were a 1987 Coupe Deville(gas) it would be sucking me dry, so I am not complaining at all.

I was more curious how others posted mpg in the 25-30 range.

Thanks

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Enough about me, how are you doing?

There are no valve adjustments on a 603. I would check timing chain stretch first and then do a compression test.

Or, as Mr. Burns called it on the Simpsons, the "acceleratrix."

"Acceleratrix", I like it !

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Diesel-guy