Where there different ALDA's produced? If so I would be interested in seeing what part #'s people had.

If I understand the ALDA correctly, it should hold a vacuum correct?

Has anyone measured the travel of the ALDA plunger and what readings did they get at what boost?

I understand its just a "environmental" device but I am not to keen on removing it. It seems that if it was performing optimally there is no reason to remove it.


I am almost certain that the fuel curve is not matching my air curve and I am wondering if the spring (11) under the aneroid capsule has weakened. I don't believe that fuel enrichment is occuring as soon as max psi is attained. If max boost was occuring at 2500 rpm I am not really feeling it until 3200. (example).


I drove a euro 300TD that really had some kick to it. Did they have ALDAs? I dont seem to remember it smoking particularly bad?



According to this the overboost switch vents at speeds greater than 2000rpm and <0.3bar the over boost switch vents for a cleaner environnent. Guess I should reinstall that bit. However since I switched over to maual transmission it appears to be stuck open. Where is the electrical signal generated from?

__________________
http://superturbodiesel.com/images/sig.04.10.jpg
1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

Im interested in learning about this as well. Some ways to check if the ALDA and switchover valve are working correctly are what I need...

__________________
-------------------------------
'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car

The ALDA will hold pressure, not vacuum. If you apply vacuum to the ALDA, you'll likely damage it permanently. Furthermore, it won't usually hold pressure completely. A bit of a leakdown past the seals is normal.

I did apply pressure to the ALDA with it on the bench, but never put a dial indicator on it. I'd guess that the travel is about .150" or so.

The ALDA responds to boost. If you get max psi (13 psi). the ALDA will have travelled all the way to it's stop. You won't get any more fuel even if you removed the ALDA from the engine.

But, at part boost, you can shift the curve of the ALDA so that it provides more fuel at a given boost. That tiny screw on the top will allow you to do this. Turn it counterclockwise about 1/2 turn and see how the vehicle behaves. If it doesn't smoke, then give it another 1/2 turn. Make sure you loosen the locknut first, and don't force the shaft. If it won't go and you break off the tip, then you are SOL.

If you go too far, you'll get black smoke on deep pedal below the onset of boost (below 2000 rpm).

My concern is that its not reaching that stop. I suppose I can pull it and manually pull the pushrod on the bottom to see what the max travel is and then see if its reaching it at 13psi.

__________________
http://superturbodiesel.com/images/sig.04.10.jpg
1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

Do an accurate timed run at 13 psi.

Then, remove the ALDA and do another timed 0-60 run.

I'll bet you that the times are identical.

However, this is provided that the ALDA sees 13psi and is functioning properly. If the ALDA is not working...........removing it will result in a massive performance increase.

This is off-topic, but...

I thought the main purpose of the ALDA was to adjust the fuel mixture based on atmospheric pressure differences due to elevation changes, not environmentally related at all.

__________________
-justin

1987 300TD, 1987 300TD
2008 R32, 2000 Passat Wagon

It also adjusts fuel qty based on boost pressure.

__________________
http://superturbodiesel.com/images/sig.04.10.jpg
1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

There is no doubt it is seeing 13psi. I am using the ARV nipple on the ALDA. I certainly do plan on removing to atleast get measurements on travel.

__________________
http://superturbodiesel.com/images/sig.04.10.jpg
1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

That is the main purpose of an ADA (yes, no L). It is found on all naturallly aspirated engines (errr.. US spec ones at least, some euro ones don't seem to have it)... There really isn't a reason to inject less fuel at altitude except for fuel mileage and soot production (which both can be argued as environmental issues ).

The ALDA does that as a side affect, and adds more fuel when there is more air available to burn it (under boost conditions). If the ALDA is removed, my understanding is that the injection pump acts like there is full boost all the time. This will result in lots of black smoke off idle... I don't know if there is any performance benefit to removing it completely, but I haven't heard of anyone benefiting from adjusting it to its max position (with the initial point being the "ideal" setting of a puff of black smoke on take off).

__________________
John Robbins
'05 E320 CDI - 240k
'87 300TD - 318k

This has been the most informative thread on the ALDA. I have never seen a cutaway of the ALDA, this helped me understand what it does. Can someone tell me how to check the boost. I have been working on my motor for a while but I'm not sure if the boost is correct or the ALDA is working properly. I have never seen BLACK smoke from the exhaust at any speed or acceleration. I don't have a tach because the stock tach is for a gas motor (I have the Diesel motor in a Jeep Wrangler). I have lack of power on hills and on takeoff. I would really like to know if I have it hooked up properly and adjusted correctly.

If you are in San Diego I could meet you somewhere. I was also looking into putting in an intercooler. Any help would be great. Thanks Jon

I disassembled an IP that did not have a functioning ALDA. You could remove the boost line going to the ALDA and the 0-60 wouldn't change at all. Long story short, I ended up killing that engine, and in grabbing the ALDA shim to use on my other SD, I noticed that there was very little vertical movement possible. Especially when compared to my other IP.

Another datapoint is that the turbo only generated 8psi of boost. I sold the turbo to another forum member, who was able to get 15psi (with no wastegate mods or boost controller). This tells me that there wasn't enough fuel to push the turbine to 15psi (IE, the wastegate was still closed at 8psi like it should have been).

As an easier step before you remove the ALDA, just disconnect/block the pressure line from the manifold and see if the performance changes. This will tell you if the ALDA is positively changing your performance any (ie, adding more fuel/responding to boost).

The overboost protection circuitry is to protect the engine (boost pressures above 16psi) and protect the transmission (the conditions you pictured plus I think those are only applicable below a certain speed). The tranny protection is because of the whole you can "powerbrake" to allow the turbo to spool up, and towing a load up a hill provides a similar experience that might generate enough torque to waste the tranny. I'm not sure what you mean by "stuck open" but if the valve in-line to the ALDA is venting, you won't get any of the ALDA's benefits. I would try bypassing that to see what difference it makes as well.

Good luck!

__________________
John Robbins
'05 E320 CDI - 240k
'87 300TD - 318k

Search the forum for how to adjust the ALDA... there are TONS of threads on it out there Should be some on checking boost as well.

__________________
John Robbins
'05 E320 CDI - 240k
'87 300TD - 318k

Just plug the boost gauge inline. I paid abotu $25 shipped for mine. Do the ALDA cleaning per diesel Giants website. Lack of power from takeoff is screaming for ALDA adjustment. Lack of power on hills is perhaps a boost problem. Get the gauge plug it in and drive around. Black smoke == to rich. No smoke == to lean.


In my particular case I think I have narrowed it down to two issues. I have a leak on the T3 flange on the exhaust manifold. I also believe I am not getting full travel on the ALDA. ForcedInduction noted in another forum that if one of the capsules is ruptured you only get 1/2 travel. That sounds pretty much like what I am experiencing.

__________________
http://superturbodiesel.com/images/sig.04.10.jpg
1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42