Hi all,

I did a quick search on how to adjust the ALDA to get a bit more power off the line, but came up with nothing on how to do it properly.

All I'm really after is for a bit more scoot when taking off so I can maneuver in traffic a bit easier/safer.

Any help?

Thanks.

Loosen the 10mm lock nut and back out the centre screw all the way.

You must check that the boost pressure is getting to the i/p through the banjo bolts and hoses across from the intake log and across the boost cut-off relay..next to the brake booster.

Most see boost between 9 and 12 psi. I run mine at around 19 psi.

Others will chime in with info' and links to previous posts about extra boost adjustments....it's been covered many times.

You may need to adjust the i/p load stop and torque screws too.

Unless you've taken apart the MW-pump and adjusted the full load, and torque capsule you don't need that much boost. Your just over spinning the turbocharger.

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1981 300TD 4 speed manual
Euro bumpers, zender valance and skirts, H&R springs, billy HD's, leveled sls, real AMG Pentas 16x8 et11, vdo boost/egt gauges intergrated into ash tray, eurolights, led 3rd brake light

Power and torque is like money....you can't have enough.

Before you go popping off about what I need to do, check with me about what I have done.
Seems you didn't read my entire post.

Woops. Did not see the bottom line. Terribly sorry.

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1981 300TD 4 speed manual
Euro bumpers, zender valance and skirts, H&R springs, billy HD's, leveled sls, real AMG Pentas 16x8 et11, vdo boost/egt gauges intergrated into ash tray, eurolights, led 3rd brake light

Apologies accepted. In our haste, we all miss info from time to time. I guess the bottom line looked like a signature line....to defeat that problem, I will make sure my posts end with some space from the bottom in future.



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Doesn't matter. 19psi is too much for anything the stock injection pump can supply. 15psi max is all the engine needs without an intercooler, 12psi with.
More boost than absolutely necessary increases exhaust pressure, especially above 4000rpm when the torque capsule is taking away fuel. The wastegate stays closed more to make the turbo spin faster.

First check your air and fuel inputs and exhaust output for no restrictions - air and fuel filters are fresh, and cat converter not plugged, before you mess with ALDA. When that's good, proceed...

by removing the ALDA off the IP completely first (yes), to see if any adjustment of it would help. (See other threads on its removal.) Just loosen it off the IP, leaving it connected to all its hosework, but not riding the injector pump.

Go for a drive with it off.

If you get immediately noticeable better off-the-line performance without the ALDA, then adjustments will yield expected improvement.

Otherwise with no extra power, then no amount of playing with ALDA (at this stage) will help your more immediate issue (whatever it is - solve that first, e.g. fix your dragging brakes, or hoist that anchor you are towing).

There are 2 ways to adjust an ALDA: shim it up, or play with the screw.

Playing with the screw risks destroying its atmospherically tight enclosure, and aneroid capsules within.

I recommend shimming the whole ALDA up where it meets the IP, or total removal and leave it off.

Note that shimming too much is equivalent to total removal, so you can fool yourself by seeing the ALDA there, yet doing no function. The "sweet spot" of a functional ALDA that you're looking for is where you still get best off-the-line performance without blowing black smoke. Start the shimming process with black smoke, then use thinner shimming to reduce smoke. You drop the shim into the nut holding the ALDA down to the IP, the type I used were copper crush washers. (I seemed to have a lot around I think from oil filter/kits you get from Benz, each one comes o-ring and crushers for the drain plug and oil canister center plug.)

A lot of people remove ALDA completely and reduce smoke with careful input of the right leg. i.e. press less on the pedal.

Black smoke is excess fuel making no extra power, ie. wasted fuel. Either YOU can modulate it with your muscles, or try to let the ALDA modulate it on your behalf. That is all it really does.

And you know that turbo is not in play off the line. You have to spool up to 2500 to make meaningful use of it. So at low speed low RPM launch stuff, that's when the ALDA is "doing its job" (of limiting your power). Worry about tweaking your turbo wastegate etc if achieving top-end power / speed is your issue. Ignore turbo things until you are scooting off the line and smiling.

I'm not a big fan of ALDA's usefulness, that is why mine sits on the bench, not on the car.

Read past posts and endless debate of pro's / con's of what else the ALDA might do in an overboost situation. My stance on that was to install a boost gauge with alarm in the car. At my altitude it's a real treat to see 1 bar / 15 psi boost under hard pressed conditions.

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Cheers!
Scott McPhee

1987 300D

I just added a shim (1.20mm) to my ALDA today and it appears to have improved the 0-2200 RPM Performance. However this is subjective at the moment. I have attempted to measure the baseline prior to this modification using my GtechPro. I hope to retest in the next few days to report back with the new information for further comparsion.

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Eric in Plano,Tx
85 300D 277K overall miles
65K on WVO (2 tank)
Rebuilt Transmission at 245k miles.

96 CE LT1
94 Nissian Hardbody
96 F250 XLT PowerStroke (also runs on WVO)

Well I thought I should chime in here again with my findings.

I completely removed the ALDA, and low end performance improved quite a lot. It don't even 'roll coal' if I floor it from a standstill. I'll be shimming the ALDA and keeping the hoses disconnected so as to keep dirt and crap from getting into the pump.

I think the next thing is to turn up fuel a little bit for more top end power.

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'85 Mercedes 300SD W126
'99.5 Jetta TDI

what is the ALDA? im not new to diesel but new to mercedes. is the banjo bolt that clogs the one on the filter above the IP. im cleanin out the cat soon and im thinkin about muffler removal. air cleaner upgrade soon too. i love this car but this one is so weak. im gettin passed by loaded tractor trailers on inclines and off the line.

Don't forget to post the year/model of your car. The original poster did neither. The OM61x (MW) pumps tend to be a lot lower on fuel delivery after 25+ years than the OM60x (M) pumps, for whatever reason. Measure boost pressure and clock the 0-60 performance with a stop watch, those will give you solid data to work with. If the car is significantly slower than factory spec, you should be able to get it back to spec with some tweaking.

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Check out my website photos, documents, and movies!

The ALDA on my 85 CD is shot. IT's been turned up all the way (by PO) and the car will not even go 5 mph if you try and adjust it down. If anyone has a good one I could use it.

Can you remove the alda on the 85? I did on my 87, but not sure about the 85 and how you would go about it if you can.....

Sure, but you are just putting a band-aid over the real problem... your IP is too low on fuel delivery. But as a cheap/easy fix, it will help for a while. BTW, it's not likely your ALDA is defective; unless something is broken internally and jamming the capsules all the way down. Would be interesting to take it apart and see.

Actually, "the PO adjusted it and now the car won't go over 5 mph" sounds like exactly what happened when I turned the screw too far on mine. The screw shears off and then you have the slowest car in the world. I bet it's been broken internally by ham-fisted screwdriver work...just like I did to mine.

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1981 Mercedes 300TD, 1994 Honda Civic Del Sol
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