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Old 11-17-2012, 05:20 AM
Flyingman's Avatar
Flyingman Flyingman is offline
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Location: Miami
Join Date: Sep 2009
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Mein Auto: 335d
Supposedly DEF is metered to inject at some % (1-3%) based on fuel flow measured. This makes sense as it is just a chemical reaction, so many parts per million of DEF to each part of fuel. 1% would be 10,000ppm of DEF?

I suspect your metering is out of whack and is injecting more DEF than it should, so this would be a defect and they should fix it.

Look at it this way, you calculate you may burn 30mpg and you expect 13,000 miles between servicves. 13,000/30 = 433 gallons of Diesel will be burned between services.

The DEF tank holds some 6 1/2gallons, so 6.5/433 = 1.5% of DEF being consumed.

The rate of injection is just too high on your car. They should fix that!

If your getting only 20mpg I would expect you will run out of DEF before you reach 13,000 miles.

Good luck!

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