WOW! ALDA adjustment makes night and day difference - PeachParts Mercedes-Benz Forum

SoyDriver Matt · #1 06-19-2004, 11:58 AM

Just got done ajusting the alda on the beater 300SD, thanks to the helful advice here, didn't want to get into it until I checked other stuff like the valves and timing, and man, could not the believe the change in acceleration. Used to have to be very patient waiting for a big enough gap in traffic to pull out, so it's pretty pleasant to be able to actually get out of the way when someones rolling up on you too fast. So far I'm up to 3/4 turn ccw, might try a little more, but don't want to push it without an EGT guage....So if you have tried everything else and your car is still a dog off the line, try it, you might like it...but maybe have a backup car incase something breaks internally.

muybweno · #2 06-19-2004, 01:05 PM

yeah i have a question about that too..
i have a 300D 78 and its non turbo... i think on my injector pump there is also an ALDA too...looks like an oldschool service ring bell on a counter top. Do you turn the whole dial? or do you use a flat head screw driver to turn the little pin head on top of that ALDA to make the adjustments...

Also i have a mity vac.... and there is a small tube comming out of that bell looking deal. can i hook up my mity vac to that line and test for pressure that way or do i need an EGR tester?

thanks

gnashd · #3 06-19-2004, 02:33 PM

I had a 76 240 D and that Old School Service bell is the filter for the oil reserve I think. If you open it up you will find a cavity that contains oil for the pump lubrication. Use your dip stick to check the oil level inside. There is a drain plug below to drain the diesel fuel out so you can replace the oil.

SoyDriver Matt · #4 06-19-2004, 02:39 PM

I don't think so, I think he's got an early 123, where the I.P. is lubed by the engine oil, unlike the 115 which does have a seperate oil resevoir, but I think is does have an alda, but I don't know jack about adjusting that type....

muybweno · #5 06-19-2004, 03:21 PM

soydriver matt:

you are correct on the service bell thingy. On most W123 from 77-83 that are the nono turbo US versions they are lubed with the engine oil from the crankcase. that oldschool bell shape deal is the ALDA if i'm not mistaken that sits on top of that injector pump. anyone know how to adjust this? of if i can use that mity vac to measure correct presure going into that ALDA

moxwell · #6 06-19-2004, 04:42 PM

I was going to post my own alda question, but I guess I will just chime in here, hope you all don't mind the intrustion. (83 300sd)

I went to adjust my alda, but I found it was turned all the way CCW already, it would not budge anymore. I have been driving it around for some time now with not much in the way of dark exhaust, none at least that can be seen in the daytime, very little at night (headlights). Can this have a detrimental effect on the engine?
I heard also that the EGR can be blocked off to improve the performance further. Anyone have any luck there?

vwbuge · #7 06-19-2004, 05:50 PM

Word of advice: DON'T GET GREEDY. I adjusted mine also and the difference was like night and day. However, there are quite a few here that took it a little too far and had to ante up for a new IP.

moxwell · #8 06-19-2004, 06:17 PM

in my case, I have only had the car a few months and not knowing how long the previous owner has had it cranked it up all the way, would turning it down some be the recomendation here? As mentioned I do not see heavy black exhaust upon heavy acceleration, in fact the only time I really saw anything significant was when an italian tuneup was performed. The car runs great. What are the signs that an IP has gone bad or is being affected? If any.

wolf_walker · #9 06-19-2004, 07:03 PM

The thing that looks like an ALDA on a non-turbo is an altitude adjustment device.

ALDA helped mine out a good bit as well, I think MB had them turned down from the get go for smog and visable smoke reasons.

muybweno · #10 06-19-2004, 07:08 PM

YES! the altitude compesator..so how do you adjust it on a non-turbo 300D?

SoyDriver Matt · #11 06-19-2004, 07:09 PM

I thought thats what the alda does, is adjusts for the changing air mass at altitude...?

Lycoming-8 · #12 06-19-2004, 11:07 PM

The altitude compensator on a non-turbo engine only adjusts fuel for altitude differences. On a turbo, the ALDA is primarily there to adjust fuel based on turbo boost. It indeed does also compensate for altitude, but that is not the primary function.

#13 06-20-2004, 12:23 AM

It should work the same way as the ALDA for a turbo engine. Less dense air = less fuel (for pollution control), more dense air = more fuel. Try adjusting the flat head screw (the one with a lock-nut on it) counter-clockwise.

muybweno · #14 06-20-2004, 12:40 AM

so on my 300D 78...with non turbo engine:turn the fuel compensator counter clockwise for more fuel---> hence more smoke???

or is it the other way around?

#15 06-20-2004, 12:52 AM

First off, I don't have a non-turbo engine, nor have I seen one up close recently. Having said that...

Based on your description, and knowing how and why the ALDA does what it does, it would seem that turning up the fuel is done in the same manner as it is on the turbo engine.

Try CCW first. If for some reason it decreases your power, turn it the other way. 1/4 turn at a time for safety.