1987 300D Turbo ALDA adjustment - PeachParts Mercedes-Benz Forum

Bolognablake · #1 05-03-2011, 11:19 PM

1987 300D, 215k miles. ALDA cap is intact. plenty of power under boost, can't get out of it's own way at idle.

How the heck are you guys adjusting it in place? I can get to the top of it at all. Black magic?

Please advise.

Thanks.

vstech · #2 05-03-2011, 11:27 PM

Are you starting out in 1st gear?

babymog · #3 05-03-2011, 11:37 PM

From across the valve cover with a long-sharp Craftsman screwdriver I have managed to twist and sever the metal band around the black plastic cap. Usually this destroys the cap also.

Once the cap is removed, it is as difficult to see and touch the adjustment, spray it first with your favorite penetrant for good juju. Loosen the lock-nut, in some cases the adjustment will turn with it. In such a case, you can stick any small piece of flat metal in to hold the adjustment after loosening the lock-nut and adjustment together 1-1/2 turns CCW, and then turn just the lock-nut back down to snug (don't over-tighten).

I have done this several times on my various 603 and 602 turbo cars. However, it seems less frustrating to buy the $15 intake gasket from NAPA (Victor Reinz brand, next day) and just remove the intake which gives the opportunity to do glow-plugs if necessary, clean the intake of EGR gunk, etc and I doubt that a first-time ALDA adjustment is possible with it on in any less time than it takes to R&R the intake (not including the extra day's worth of "while I'm in there" stuff that will happen as soon as you remove the intake.

It helps to have long, slender, but fairly muscular fingers, a high threshold for pain, and a child nearby so that you can't swear or throw things.

woodboat3 · #4 05-04-2011, 12:25 AM

This thread suggest 6 minutes to remove and replace ALDA with intake on. That is quick
OM603 ALDA removal instructions

Bolognablake · #5 05-04-2011, 01:00 AM

Good call. I didn't think of adjusting off the vehicle.

sjh · #6 05-04-2011, 03:34 AM

This was my first posting from 6 months ago. I don't know why I used some many frames to say what I did but live and learn.

My earlier diesels (115 & 123) had easy access to the the IP and ADA so when I saw the ALDA buried in the 124 I had a challenge.

I can now change my ALDA setting in less than 3 minutes. Hope it helps.

Adjusting the ALDA in a 602 Engine

babymog · #7 05-04-2011, 11:20 AM

Quote:

Originally Posted by woodboat3

This thread suggest 6 minutes to remove and replace ALDA with intake on. That is quick
OM603 ALDA removal instructions

I've tried to remove the ALDA with everything except the washer-bottle in place, and don't have a large wrench short enough to make it work in a 124. Perhaps if your wrench is shorter, or the hex in the right position to get it started (mine never are), but no luck.

Bolognablake · #8 05-04-2011, 12:12 PM

Quote:

Originally Posted by woodboat3

This thread suggest 6 minutes to remove and replace ALDA with intake on. That is quick
OM603 ALDA removal instructions

I was able to get it off in like three minutes using this guide.

I adjusted it 1.25 turns CCW and it feels like I'm driving a normal car! It'll even spin the tires, Haha.

No smoke under normal acceleration, just a slight puff under WOT (while performing the wheel spin test).

Thanks again guys!

woodboat3 · #9 05-04-2011, 12:37 PM

glad it worked. I might even try it. My 300SDL runs so well right now I was afraid to touch the ALDA.

Bolognablake · #10 05-04-2011, 07:19 PM

Quote:

Originally Posted by woodboat3

glad it worked. I might even try it. My 300SDL runs so well right now I was afraid to touch the ALDA.

If it makes you feel better about it, my 300D ran (still runs) great, I was just tired of putting my foot to the floor to start from at every stop light just to keep up with traffic.

It does just fine now. The only problem is I have to relearn how to drive it, i.e. I only have to stomp the accelerator pedal 1/4 of what I used to take off.

winmutt · #11 05-04-2011, 10:09 PM

There is no way to take my ALDA off. It seems some people are clocked out far enough to do it. I suppose I could do it by adjusting the pump but I'd just as soon not do that.

33rain · #12 08-18-2012, 12:09 PM

Hi,

I just bought an 1987 300d. The guy I bought it from had removed the ALDA from the injector pump. Being more interested in fuel economy then power I re-installed the ALDA, however doing so lead to a significant loss of power, more then I find tolerable.

I plan on removing the ALDA for the moment. But long term should I leave the ALDA off? Will this effect fuel economy if I drive conservatively? Will adjusting the ALDA solve the power issues and if so could some one point me in the direction of a guide to adjusting the ALDA. I get the impression that you turn the screw on the top of the ALDA but I'm not sure.

Thanks

sixto · #13 08-18-2012, 01:34 PM

The ALDA needs a boost signal to function properly. There is a fitting on the intake manifold above the ALDA. A line from that fitting goes to the overboost protection solenoid to the ALDA with a split to the transmission vacuum amplifier. If you post a picture of that section of the engine, we can help you get a boost signal line in place or confirm you hooked it up correctly.

It's possible the previous owner removed the ALDA because it's broken Do you have a MityVac with pressure outlet to see if the ALDA holds about 15 psi? Don't apply vacuum to the ALDA!

Sixto
87 300D

33rain · #14 08-18-2012, 02:00 PM

I'm pretty sure I connected the ALDA correctly. The guy I bought it from showed me the lines to reconnect. Perhaps I just needed to hit the accelerator harder then I was expecting when the ALDA was installed.

Unfortunately I do not have a MityVac to test the ALDA.

I have attached an image with the tube I connected to the ALDA circled. I apologize for the image quality.