My 78 300D has an altitude compensator. It is a diaphragm looking thing on top of the IP. Do you have one? If so, check for functionality.
My car does not always downshift when it is convenient. I have my control rod set optimally for most driving conditions and reduction of flare. If I need to, I drop the shifter down instead of flooring it.
I had the idea of setting up a microswitch that I could adjust, and maybee I could make it bypassable, as when I travel around Vermont I would like to control downshifts a litte better.
I dove a 2.2L automatic Plymouth minivan X-country. The thing was a dog but the only place that It could not bring me was the high altitudes of AZ becaouse it was a carbureted engine and was running way too rich over 7K ft.
My stock 77 Puch Maxi blows right by kitted bikes on steep hills. The kitted dudes would often soft sieze too.
If I were to do it again, I would in my 300D with a ped on the back.
The Haynes manual describes setting up the linkages for max. travel. Check you linkage for wide open throttle.

Make sure your air cleaner element is not restricting air flow.
Check that linkage as suggested. Also, verify that the (on the firewall) throttle bushing is not shot.

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Codifex
1981 240D ChinaBlue (Got her running with a donor engine.)
1983 300DTurbo w/sunroof.
1984 300TD manual sunroof. (Electrical Gremlins)

I did the same, but up to 14,000 feet with two other passengers and a fully loaded car. It was slow, no question about that, but it will get you where you want to go. As previous posters have mentioned, 25 mph seems a bit too slow, how steep was the grade?

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79 EURO 300D
80 240D

14,000ft? did you have to bring oxygen for you and the 240?

Charlie

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

Forget oxygen, didn't the Top Gear crew take Viagra to prevent edema at that altitude?

Sixto
87 300D

^^^......hahahaha

Well, I think it was closer to 13,000, but I rounded up for effect . My friends, along with myself, were on our way to Colorado Springs, Colorado and decided to take a side route which led us--and presumably my car--to the highest point it would ever see.

Pikes Peak (which you can drive) is north of 14,000 feet, according to Wikipedia.

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79 EURO 300D
80 240D

Most 240ds are very old. Most have been neglected from my viewpoint. They are also about the only car on the market that you have to use everything they are capable of delivering more often that any other car I can think of.

So it is up to the owner to get them back into the best possible motor output condtion. The majority I have seen of them can be improved With a little effort.

Every little bit helps and is nice to have when the car is worked hard. Examine throttle linkages critically, rebuild the lift pump, Put the higher pressure spring in it at the same time. Or rebuild the lift pump from a five cylinder and install it, check the fuel pressure available in the bottom of the injection pump. Change or clean all filters, adjust the valves, Have the injectors checked, check for chain stretch and injection pump timing. check for brake calipers that are dragging a little more than they should be.

A lot of the mentioned items have not been even looked at for too long a time on many examples of the 240d. You may pick up a noticeable horsepower increase by doing them.

Most items are only labour intensive rather than cost intensive. I would not take a 240d into mountain service without checking at least most of them. Even more so with the automatic.

I take my 220D all over Colorado. I live at around 8,000 ft and work around 6,000ft. On the weekends I go up to 10,000 often. I have also been to the top of Pikes Peak (14,000 +). You will be fine after addressing a few other problems. Go enjoy the drive!

My 1982 240d could only make it to the entrance of Pike's Peak toll road before calling it quits. At that time the valves were severely out of adjustment and the accelerator linkages as well. My estimate was maybe 50% of the accelerator linkage travel was left to the pedal. It's a different animal today with the adjusted (and repaired) linkage and properly adjusted valves. I plan someday to return and complete the journey.

The car was only there because it was being driven to it's new home in St. Louis after being purchased in San Diego.

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Own:
1970 Mercedes 250c, 1976 International Scout II, 1982 Mercedes 240d, 1997 Honda Accord Wagon, 1998 Acura Integra Type-R, 2009 Mazda5.
Owned:
1974 International 100 pickup, 1975 International Scout II, 1981 Mercedes 240d, 1985 Mercedes 300SD, 1988 Honda Accord, 1988 Ford Thunderbird, 1991 Honda Accord, 1996 Geo Metro, 1996 Ford F150, 1996 Dodge Grand Caravan, 1997 Honda Accord, 2003 Acura TL-S, 2003 Yamaha V-star.

well thanks for all the responses! well i checked the linkages and many of you were right, with the pedal at the floor i still have PLENTY of play in the linkage before getting the IP fully open. looked at the FSM but I don't have the adjustment screw that it mentions as part of the full throttle adjustment.

think i should just lengthen the final (i have 4 total) rod? i think i would need an inch or more and not sure if i can get that from just adjusting that one linkage???

too many times the car has kept me from getting to work in a timely manner in the morning so i'm not going to mess with anything tonight, but will try any suggestions tommorow evening.

also, for what its worth, the engine was swapped on the car and i do remember that the linkages didn't quite go together the same. can't remember what the problem/solution was and the FSM doesn't have a good overview of all the rods so i have nothing to compare to.

I live in the Springs and my car gets around town just fine, though there is a hill a few blocks from me (the one just east of Woodmen and Union, for those of you familiar with the Springs) that my car struggles with if I'm not flooring it when I approach it. I start up that hill and my speed drops dramatically. I find that if I don't manually downshift (by this I mean taking the stick down to S, as my car is an automatic) upon my speed dropping to 40, it won't downshift at all and I'll lug up that hill (though it'll automatically downshift on its own if I end up dropping to 20).

There's one other hill far more massive than that one: the climb on Fillmore just west of I-25. Have never attempted that in my car, never will

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1983 240D, 272K+ miles (odo broke)

My 240D and I have lived in Tennessee, Mexico, Colorado and Arkansas. I have driven it everywhere in all kinds of weather and altitudes. Follow the advice of keeping your car in good condition. I keep my valves adjusted and replaced the timing chain at ~150K. Make sure all your linkage is correct.

Keep your foot in it and drive it like you stole it. If it's well maintained you can't hurt it.

Also, on the shifter, S = Slope.............use it! They made the auto trans manually shiftable for a reason. Shift it, you won't hurt it. I always thought it was worse to lug a diesel rather than rev it.

Clay

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2002 E320 Sedan 93K Designo Mocha Black Metallic!
1995 E320 Wagon 205K Black Wagon
1982 240D 183K SloPoke

I believe each of these cars are the final production year for that model.

Still not enough attention is given to making sure the fuel pressure in the base of the injection pump is where it should be. Especially on the 616 engines. The cost of this oversight may be the loss of the first connecting rod bearing over a very long time period.

The lift pump also puts out less operational pressure than the 617s. So filter restriction is a more serious issue in lowering the available fuel pressure. Much earlier than on the 617s anyways.

The 616 will run with lower fuel pressure than it should have. Many things seem to be effected as a result. Certainly power is lower and that to me is important alone. It is also reasonable to conclude that fuel milage may be lower as well.

It is such simple fuel supply system it is a shame not to keep it up to what it should be. Also if you know it is in good shape fewer problems may arrise from it. So it is preventative in nature as well.

The european examples of the 616 use a different fuel injection pump that for whatever reason does not seem to cause the same issue. That is the number one rod bearing failures.

As far as I can find out failure on those european models are almost unknown in comparison. Where almost every time a rod bearing failure occurs it is on the number one cylinder on the american injection pump versions.

You cannot optomise power output until you are sure you have decent fuel supply pressure. It to me is the most neglected area of the 616 cars.

To go on a long trip without having a clue of what you have does not make a lot of common sense to me. If it costs a lot of money to put it into good condition yourself I might semi understand. It generally speaking does not though.

Just because the car runs is no indicator of the condition one way or another. You have to check it to really know. The exception perhaps is if the car is giving very close to thirty miles per gallon on the highway. I feel you cannot get it with low fuel supply pressure at this time.

alright alright. so many success stories of mountain adventures that no one noticed that (maybe) i found the problem, but am still unsure of how to progress. any thoughts. if not i'm just gonna start readjusting stuff and see if i don't break anything....

The best way I've found to adjust mine:
There is a plastic bushing on the firewall that is operated by the pedal linkage. There is a straight rod (maybe 10" long and horizontal) from that bushing to the Rube Goldberg linkage on the injection pump/engine. At the front end of that rod is a curved adjustment slot with a bolt holding it in position on the linkage. Loosen the bolt (10mm wrench) slightly and rotate the assembly so that you get full linkage travel with full pedal travel. Also check the integrity of the aforementioned plastic bushing.
Hope that helps.

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1983 M-B 240D-Gone too.
1976 M-B 300D-Departed.

"Good" is the worst enemy of "Great".