Diesel performance and altitude...
 

Have many here had bad experiences operating diesels at high altititudes? If so, when closer to sea level, do the problems go away?

Thanks for your thoughts

Jim,

I live at 6500' and regularly drive at altitudes of 3000' - 8500'. No problems.

The only "problem" is a loss of power at high altitude. A non-turbo diesel suffers much worse. A turbo car will be affected less, as long as the boost is up. I live near sea level and my car has very good power. But when I drive up in Reno, which is over 6000 ft elevation, the car becomes noticeably more sluggish off idle. When I return to sea level the car goes back to normal.

High Altitude Problems
 

Dave,

I just got out west and caught up with my 300TD that made the 1800mi trip the week before. Before I arrived my wife warned me that the car was like it's original self with no power to accelerate. Dangerously slow.

I knew right away that the long trip must have plugged the pressure line to the ADLA. AS soon as I arrived at DIA I removed that and sure enough -- plugged as could be. I cleaned it out (I've been using carb cleaner spary does that make sense? Or is there something better?). Everything seemed to be fixed, but I still thought it was a little slow off the line.

By the next day when I headed out to the mountains I was sure that I had severe low speed power problems. Even in the foothills around 8000 feet. If I wasn't in the the boost I was a turtle. I also noticed that I had no black cloud on full throtle acceleration.

Could this be something more than just my ALDA needing adjustment? It seems to be reducing fuel at the higher altitudes more than it should.

I also burned quite a bit of oil on the steep stuff (Old Falls road to the visitor center in the Rocky Mountain National Park and a forest road to a cabin in the foot hills. Steep enough to make the whole family nervous escpecially when the engine felt like it wouldn't pull us away from the edge!)

Anyway it seems that altitude affect was clear and present in my case. Thanks

I took a trip thru oregon, idaho and utah a few months ago. It did fine on the freeway ect, but in traffic, it was terrible. I had to run with the airconditioning off in towns if I didn't want to hold up traffic. Once the turbo kicked in, it took off. Some where in the past we had a thread about this, and it seems there was a way to adjust for altitude in the injection timing or something. Might do a search if your curious.

This Winter, I used my 240D to go in the mountain (at a altitude of 2000m).
Everithing was OK except :
- the lack of power to climb the hill (but how can it be different with only 72hp for a car fully loaded weighting maybe 4000lb ;) )
- the difficult start in the morning due to the low temperature
- the strangest phenomena to finish : when I was going down the hill using engine brake, time to time the engine was running jerky and shaking the whole car. I was obliged to accelerate a little bit to stop that. Once I left the moutain, it didn't appear anymore.

The "s" gear...
 

I don't know about euro 240Ds, but US delivery ones with auto trans have a gear setting marked "s"...which stands for "slope," in case you don't have an owners manual anymore.

This setting IS a help in getting up long, steep hills.

Yes the Euro trans have that but not mine because I got a stick shift ! ;)

JimB+

I was out running everything in my '80 300SD on the interstate near Vail CO (about 10,000 feet) everything on the road, even the V8s. 60 MPH minimum in "S" at 4000 RPM on the steepest slope. Man was that fun. Can't wait to try the '87 300 SDL there.

P E H

Hi Mike,

Hmmm, that's odd that the ALDA line plugged up so soon after the new head installation. :confused: The ALDA shouldn't have too much effect at high altitude on a turbo car, but you may be correct in your theory. Hopefully the car returns to normal at low elevations (below ~2000 ft). If not, something isn't right. Assuming the head/cam/chain is all fine after the repairs, I'd suspect the I/P especially if it hasn't been calibrated or replaced in the last ~100kmi. Wouldn't hurt to check the injector spray pattern either, again if it's been 100kmi+ since last checked...but I'd do an Italian tuneup first. :D

Bummer about the oil consumption! I still have that problem with my new head, due to the screwed up valve seals (or guides). But yours should have been OK, or so I thought... Before the seal problem I was getting about 5000-7500 miles per quart, or at the add point when changing the Delvac-1 at 10kmi intervals.

Keep us posted...


Regards,

Yup - off the line up here where I live (9600 ft) its mighty slow - but once your going the hills dont do too much to slow you down - I just got back from WYO and I couldn't believe the difference! ALSO at lower levals I noticed the engine ran much quieter for some reason - why I dont know, mabe the truck stop fuel did me good!

actually I have had altitude problems with the car being too rich and failing to start-up at high altitudes. Iif anyone has messed with the fuel enrichment adjustment that is normally sealed (on the top of the ALDA) they will know what I'm talking about...I'm not sure how to get it back to normal, just need to trial and error.

I noted this same phenomena in another post but I live at just 3200 feet and just ran down to seal level.
At sea level the car runs great with NO smoke. At home it smokes like a bad dog and like one of the previous posters I shutoff the a/c regularly when taking off from an intersection. Not for the addl power mind you though but to limit the smoke curling out the back.

I have a pneumatic governor that has a line from the intake manifold to the back of the IP and I fear that something in there has gone bad as it does not seem to limit the fuel for the altitude as I thought it is supposed to.

BTW- great relief to see the car quit smoiking as I was sure that I was in for a big project i.e. rebuild...

Altitude 8000 +/-
 

Well, I live at around 8000' and commute to work, 40 miles, which is about 4500'. My 84 CD run's just fine but there is a bit of a difference at home, not quite as much pick up till the turbo kicks in. The TD was about the same. I will say that the climb up Sherwin Grade, 10 miles @ 6%, is not a challenge for the CD and wasn't for the TD either.


84 300TD 150,000m(sold)
84 300CD 200,000m
01 Toyota Sequoia Limited 15,000m

Just experienced this phenomenon on a trip from the Valley to Tahoe this past weekend. Would someone be kind enough to explain why this is? Power was extremely weak up to boost. Tahoe is ~6,200 feet elevation. Performance appeared back to normal <4,000 feet.