Altitude adjustment for MB 300SDL

On a recent trip to Taos, NM my 300SDL did not like the altitude (8000 ft plus) I barely could get it started every morning, it smoked heavily (Very embarrasing!) and lacked its usual "OOOOMPH" until it was hot.
A repair shop in Santa Fe replaced my glow plugs and charged an exorbitant amount of money! NO CHANGE in performance, however....the car still did not run right. I know now, that I got taken to the cleaners by the shop....a hard lesson to be learned, especially when you're on vacation! Now, someone told me about an Altitude sensor or adjustment, but was somewhat vage about that. Any one with some more info on this? THANKS
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Forget it.
The ALDA is an altitude adjustment that's used to add fuel to the motor for brisk acceleration as the turbo's boost increases.
At high altitudes the air is thinner and the atmospheric pressure is less than at sea level so the ALDA actually reduces the fuel to prevent smoking which is caused by too much fuel for the available oxygen. The smoking proved there was plenty of fuel
No, the problem with your motor is that its compression, while still OK at sea level, is marginal at such altitude. The canary in the coal mine signal.
A compression test will be truth time before the overhaul.
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T.G. Lambach wrote:

Thanks for the (somewhat depressing!) info, T.G. The car is a 1987 with 160k miles on the engine....barely broken in for a Diesel, don't you think? My previous one had well over 500k miles on it, when it got distroyed by a mechanic! But nevertheless, I'll check the compression (difficult to do with crossed fingers!)
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First, try to determine if anyone "tweaked" the ALDA's adjustment (from factory spec). Some guys think cranking it toward more fuel will increase power which it does but also makes the motor smoke and generally use more fuel than otherwise. There's a balance between power and smoke.
But as to the hard starting, high altitude works against any motor. The test for yours will be when the weather turns cold. If it then is also difficult to start then the compression ought to be checked, otherwise chalk it up to altitude and keep those fingers crossed.
ALDA is on the top rear of the injection pump and has a plastic line going to it from the intake manifold.
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Also make sure the ALDA is not broken. There is a ceramic piece inside that can be broken by "adjusting" it.
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T.G. Lambach wrote:

Thanks again T.G. I think ,I just had a lucky break.....it got a little cooler here last night at 3000 ft elevation (Well, cooler for Southern California is about 55 degrees ) The car started, no problem, no smoke either. I also found the plastic line disconnected with a small screw in it to plug it up....It must be the line you're refering to. I don't know why I didn't see this before. Someone must have tinkered with the ALDA for exactly those reasons you describe. May be this is it. I'll keep you all posted> Of course to really test it, I will have to go back to Taos! I know my wife wouldn't mind! Thanks again
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It's sealed at the factory; if it's still sealed it's original.
Was your previous car a 4, 5 or 6 cyl diesel?
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Richard Sexton wrote:

It was a 5 cylinder engine (300sd)
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The 5's last forever, the 6's have issues.
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I purchased a 83 300TD whit 24000 miles, imported and modified for the US.
The car was having a problem whit the acceleration, and sometime did smoke.
First time when I was in Lake Tahoe for skiing, the cold car went to "crawl mode",
and stayed in that mode until it warmed up.
I investigated the reason, and find the altitude regulator nearly disconnected.
Some "skilled mechanic" who worked on the US conversion,
broke the adjustment seal and loosened the connection.
I made it home. At see level I adjusted the Altitude sensor so that it barely pulled on the
connection arm. The car was perfectly functioning, not smoking anymore,
no problems whit altitude, and no problems whit cold start.
I put 230000 miles into the car and never had any problem whit it.
I replaced whit a new S430. Now I have much more problems.
Pete

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PM wrote:

Thank you, too Pete for your help. Just a little personal story in addition to yours: I thought my previous Diesel would be able to go a million miles. My wife brought the car in for a simple oil change. When the mechanic tightened the oil filter cap, (after changing the oil) he pulled one of the studs out of the housing ! ! ! He let her drive the car home without telling her or even temporarely fixing it. It takes less than 5 miles to lose 9 quarts of oil, you'll leave a tell tale streak on the road and the engine gives out after one more mile. What a nice fight that turned out to be. I was on the road because of my job and he tried to blame it on my wife the car mechanic.... (She wouldn't know the difference of radiator or the spare tire.) It took 3 month to get them to pay for a new (used) engine. I sold it to after that. The old engine had over 500 k miles on it...I hated to lose that car Good luck with your 300 td

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colonel klink wrote:

Pete, I meant to say Good Luck with your new MB.

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colonel klink wrote:

Pete, I meant to say Good Luck with your new MB

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