Ok guys. I have adjusted the valves, replaced the fuel filters, replaced the air filter, made sure I have the proper amount of air in my tires...in short I have done everything I can think of and my wife's 300D is still getting about 18 mpg. I have read as many posts as I can find. I need any other helpfull hints you all can provide. Fuel isn't as cheap as it used to be and I would like to get as many mpg as possible.

Thanks in advance,
Mike

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Mike

'80 300D
'84 300D
'85 300D
'87 300D

Mike,

When I had the 123, I found the mileage slowly dropped from 27 down to 23 or so, over the course of four years and the addition of 100K miles. I did all of the things that you did and nothing improved it. Finally, someone else drove it and clearly noticed that it was low on power. You needed to really press your foot down to get it to take off at all. He commented that this was not normal. I was quite sure that the cam timing had to be off by quite a bit because the IP timing was adjusted carefully to be right on spec. I never followed it up to confirm that I needed a new chain before I sold it, but, it is my suspicion that the timing chain was sufficiently stretched to cause very poor performance.

If it is not the chain, the only thing left is low compression on one or more cylinders.

check to see if you have any dragging brakes by feeling the rims after a drive. If one is hotter than the others, that's the dragging caliper. Also, check for fuel leaks at every connection of the fuel system.

Poor perfromance can also be caused by badly worn injectors.

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Never a dull moment at Berry Hill Farm.

Whoa, 18 sounds really low. Does it smoke much? You might have to adjust the pump
a bit, someone may have overdone it at one time. (Too far out on the aneroid.)

Another idea, what about the odometer gear? If it's slipping a little...it'll show less than
actual travel...which would translate into a false mpg reading.

Not too long ago I swapped in a set of used injectors with about half the mileage of my old ones. I cleaned them before installing them by soaking each one separately overnight in carb cleaner. I also used new heat shields as it is highly recommended to do that whenever you replace your injectors. I used to get around 21 MPG's with the old injectors. At my most recent fill up today I got over 24 MPG's, not great for a typical 300DT but it was higher than what the sticker price EPA statement of 22 MPG's for my CA emissions model. It also has more power than before and it idles much smoother as well.

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DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012

I'm not lacking any power in this car. She gets up and goes pretty good. I know I don't any fuel leaks anywhere...I have done a thorough search and fixed the two I found. I had a leak around on of the injectors and the bypass hoses were leaking a little. how do you know if you have worn injectors? I did replace one of the injectors a few months ago because it was leaking diesel. I had hoped this would solve my poor mileage problem, but it didn't even buy me 1 more mpg.

thanks,
Mike

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Mike

'80 300D
'84 300D
'85 300D
'87 300D

I too had thought I had enough power because that was what I was used to. After I replaced the injectors with "newer" ones I felt a significant difference.
When replacing injectors, its recommended to change all of them as a set. In a gasser, you wouldn't just change one spark plug.

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DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012