ALDA adjustment - what causes it?
 

I have read many posts on the adjustment of the ALDA (mine is a 85 300TD CA) approx. 160K miles) My question is : What happens (either in IP or otherwise) that causes us to adjust this part? Is the pump going out of it proper setting? - Due to age, etc. Is it the engine? By the way - I had an extra ALDA (untampered) - I had been adjusting mine - had screw maxed. Had new one put on with shim - When I checked mpg - I gained 5 mpg!


Thanks

Steve

The calibration of the pump tends to be on the lean side. This prevents overfueling the engine and the resultant black smoke. So, slight adjustments to the ALDA on older engines tends to give a little better pedal response at lower speeds by adding more fuel. It's a fine line, however, before you start wasting fuel and the fuel economy drops.

FWIW, the ALDA on my wagon is cranked out to the stop...sure it smokes a bit on heavy acceleration but adding some B100 or WVO practically eliminates the smoke. I cannot figure out why but, my economy actually improved after the adjustment (24avg before, 26avg after). Having the ALDA there makes all the difference in the world!!!

just curious here.. does a 240D manual trans have the ALDA? I could not see one on mine..... :confused:

No ALDA (it's a turbo thang). However, there is an altitude compensator on the n/a injection pumps.