This is a kind of continuation of another post that got off track.

I thought I had broken my ALDA. I was fiddling with it and ended up turning it all the way in and tried driving my wagon. I had substantial increase in power!! i mean a huge difference. So the ALDA wasn't broken after all. I was under the impression that you needed to turn the screw out inorder to enrich the mixture and get more power. Why would the opposite be the case for me? Would it have something to do with living at 8000ft? Anyway i'm happy to have more power but am curious as to the dynamics. Also my transmission if shifting really bad now but there was a point when i adjusted the alda that my trans was shifting nice and smooth but I had no power, now it is the opposite. Any Ideas? Thanks again! John

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1982 300TD

The ALDA is an aneroid barometer, hooked up to the boost so that also "measures" manifold pressure rather than just outside pressure.

The anaeroid collapses with higher pressure, so that it takes pressure off a pin in the IP -- turning the screw CCW gives more fuel, CW gives less, I think (being dyslexic, I may have that backwards). It may have something to do with the altitude, certainly, but if you screwed it all the way in you must have been running very rich before (with lots of smoke, too).

ALDA adjustment has nothing to do with tranny shifting except for the possibility that you have a bad vac line that you moved while messing about, and in one position it sealed better. Check ALL the vac and boost lines associated with the blue canister on the fender, including the one going to the tranny. They all must seal properly, and they are all probably bad.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Before adjusting the alda it was still sealed from the factory. i had to cut the little sheet metal cover off to gt to the adjusting screw.

Here is a quote from a repair book
"Here is an added benefit of getting the ALDA operating properly. You may suddenly find your transmission is shifting better.(which I did at one point) If your engine power is lagging behind your throttle setting, your transmission may be "tricked" into shifting at the wrong time. For you turbo diesel owners be sure to clean the banjo fitting and adjust the alda before attempting to adjust your transmission. This little tip can suddenly cure a number of ills."

It does not say anything about altitude though. Thanks, John

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1982 300TD

John:

I also live at 8000 ft (for about 6-7 months of the year) and I haven't found the difference in altitude between my 8000 ft location and my 3000 ft location to be that great. Granted, I don't have quite as much power at 8000 ft, but the turbo almost equalizes the difference.

I hasten to add that everything on my '82 300D turbo is in good shape and is working properly. On a previous car with less than perfect compression, starting was difficult at 8000 ft but, once it was running, altitude didn't make that much difference either. I know that you lose about 3% of your oxygen with each 1000 ft increase in altitude, but the turbo seems to compensate rather well.

I would continue your troubleshooting. I suspect something other than just altitude is giving you a problem.

Just my $.02..

Wes

Phree,
I'm curious, what is the title and who is the author of this repair book you mention?

Thoughts on shifting changes...
A change in shifting after an adjustment to the ALDA would, IMO, most likely be a result of the engine now creating more power in relationship to a given throttle setting. Since the some of the shifting characteristics of the transmission are governed by the throttle positioned vacuum bleed-off valve on the IP, reduced throttle displacement (as a result of increased power) will leave a higher vacuum on the modulator and affect (ie softer shifts) shifting of the transmission.

Does this make sense?

R Leo

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Never a dull moment at Berry Hill Farm.

I have broken off the first connection in the large line going to the brake booster. I tried connecting all my lines to the one remaining connection but the IP connection bleeds off the vacuum so fast that my engine won't shut off. Is there a way to repair that fitting? I just have it blocked off right now and my tranny is flaring on the 1-2 and 2-3 shifts (jumps 100-200rpm before completing shift).

The line to the booster comes only as a complete assembly, but it isn't too expensive. Replace it, and most of the vac problems (including funny shift feel) will probably go away -- if it was brittle enough for you to accidentally snap a fitting off, the rest are probably cracked.

Turbo boost signal goes to the vac amplifier for the tranny, too, so if you got the engine running better and the boost higher, it can make a difference, but shouldn't be that much.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

You need to replace the whole line, because the connector you broke off is more than a connector. It is a metered orrifice which would explain the change in shifting characteristics. I was going to say that how the engine runs has no affect on the trans, because the vacuum comes from a cam driven pump on the front of the engine, R Leo made a good point about throttle position. I think he is spot on.

Peter

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Auto Zentral Ltd.

The name of the book is "Performance Tuning and Repair" Available at www.**************.com It is an excellent book and has helped me tremendously. Thanks everyone for all the advice I'm sure I'll figure it all out eventually. John

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1982 300TD