Sluggy 300D. ALDA? Turbo? help! - PeachParts Mercedes-Benz Forum

dufflespank · #1 05-12-2006, 02:06 AM

Hey, I am fairly new to cars, but I find that I am fairly competent with what I've tried so far. I am actually 90% done with the installation of a wvo kit. I've actually taken a break on the wvo and spent my time tuning up my car. Good thing I found this killer forum, it has been very informative.

Anyways. From what I hear and see on this forum, I've concluded that my 300D is out of tune. These turbos are supposed to be FAST, and my benz is a real SLUG. I think my 0-60 is like 20 or 25 seconds or something. My top up-hill speed is 35mph. I have to plan my freeway entries according to which on-ramps are downhill.

Today I took a good, long look under the hood after reading this forum for hours. I don't think I have that Trap Oxidizer, but I am not certain. Can anyone post a picture of one of these?

I also checked out my ALDA. It seems as if my alda unit (the square component on top of the IP) does not have any sort of banjo bolt fitting. Am I looking in the wrong place for the banjo bolt? I also can't seem to locate the switchover valve for the alda. My exhaust manifold lies directly above the alda and all of the other "fun to tweak" components of the car. Pretty bunk. How much of a job is it to remove the exhaust manifold and re-attach it?

And one last super newb question. Where exactly is the Turbocharger located, and how can I verify that it is working? Is it in that oval shaped black plastic casing on the front passenger side of the engine compartment?

Thanks a bunch!

Hit Man X · #2 05-12-2006, 03:11 AM

Bypass the overboost solenoid to see if it's plugged up, mine was on the SDL. If not, the fitting on the intake manifold could be caked up too.

TrapOx looks like a giant football under the hood, you'd know if you had one.

Exhaust manifold is on the passenger side of the vehicle... ALDA on the driver side.

mobetta · #3 05-12-2006, 08:27 AM

the banjo that gets clogged is on the intake manifold. pass. side rear of engine, careful- the old vacuum lines are brittle( dont ask how i know) what year is your car? turbo is under air cleaner assy.

dufflespank · #4 05-12-2006, 09:55 AM

It's a 1987 MB 300D. I thought that the banjo bolt and fitting were attached to the little square alda unit on top of the IP. That's what it looks like on Diesel Giant. Also, I am interested in trying to adjust it via the screw on top. What is the recommended amount of turns? That's what it looks like on Diesel Giant.

Hit Man, what solenoid are you refering to, and where can I locate it?

P.E.Haiges · #5 05-12-2006, 10:25 AM

duffle,

Before you screw around with the ALDA, check the banjo bolt, overboost solonoid, lines from banjo bolt to overboost solonoid and solonoid to ALDA, intake manifold crossover and turbo boost.

The above should all be in perfect operating condition before the ALDA is touched.

P E H

SD Blue · #6 05-12-2006, 10:33 AM

Sneak what vehicle you are talking about into your signature (under User CP).

On your vehicle the alda set-up will have slight changes. If I recall, from what I have read, there are barbed fittings rather than banjo bolts. Clean and check for no obstructions before making adjustments.

Also check/change fuel filters, transmission fluid levels.

2.5Turbo · #7 05-12-2006, 11:09 AM

Mine had the same problem, but wasn't nearly as slow as yours

Not sure if it's the same on the 603, but on the 602 engine the pressure line hooks up to a fitting on the end of the intake manifold. It's pretty obvious, it's above the IP, and is the only fitting on the manifold that has a hose coming off of it. Mine went directly into a rubber 90 degree elbow fitting. Don't confuse the hose with the wire coming off the pressure sensor. Disconnect the hose and look inside. Is it all gunked up? It most likely is, and needs to be cleaned. Clean out the hose, and then take the fitting out of the intake manifold. Clean that up, getting all the gunk out of the tiny hole that they expect to not get clogged with EGR crud and blowby oil

. Mine was totally caked. A cup of solvent, a 14ga wire, and a bunch of paper towels later, my car was getting a 12.5 second 0-60.

Put it all back together and it should be giving you sub-12 second 0-60 times. Your model is the pre-606 hotrod MB turbodiesel, it should be faster than any other diesel up to 1995, and it still may be slightly faster than the non-turbo 606 cars from 95-97, but I don't have any specs. Just make sure the head doesn't crack

dufflespank · #8 05-12-2006, 08:11 PM

Hey!

So, earlier this afternoon, I pulled out that fitting from the intake manifold. Fortunately, it was totally clogged! I used some degreaser, some wire, water and paper towels to clean the fitting out. I also cleaned the thick, out rubber hose on both ends of the vacuum line. Is the switchover unit the small black device right beside the windshield wiper fluid? I think it is, but it looks nothing like the ones I've seen in pictures of slightly older models. Both ends of the line were pretty gunked up, so I removed it and ran a pipe cleaner down it to get rid of the gunk.

I took the car for a test drive, and there was definitely a noticeable difference! Before the cleaning, my car could never hit 4000 rpm. Now, it can, and my 0-60 time is probably 12-15 seconds. I'll have to time to it to verify.

This is such an easy fix, and so worthwhile. I also changed out my fuel filter last night; that may have helped too. The filter must have been old. It said "Mercedes-Benz" on it.

Should I tweak the alda unit to improve performance?

Diesel Giant · #9 05-12-2006, 08:13 PM

Here is how to get that system up to snuff.

http://dieselgiant.com/mercedesaldaboostsystemservi.htm

Hit Man X · #10 05-12-2006, 08:26 PM

Quote:

Originally Posted by dufflespank

Should I tweak the alda unit to improve performance?

YES, it helps quite a bit off a dead stop performance. Search for me as the thread starter. You'll have pictures, info, testing, etc.

Jadavis · #11 05-15-2006, 06:44 PM

Quote:

Originally Posted by dufflespank

Hey!
I think it is, but it looks nothing like the ones I've seen in pictures of slightly older models. Both ends of the line were pretty gunked up, so I removed it and ran a pipe cleaner down it to get rid of the gunk.

What the heck does it look like? For some reason I thought that the photos on the diesel giant were for the 603 engine. Boy was I wrong. I guess I'll go back out and see if I can find it by function and not by match the photo.

I did find out that I have the dreaded 14 head.

I just got my 1987 300D Turbo this week. I am waiting on my plates to arrive.

-Jim

Jadavis · #12 05-15-2006, 08:16 PM

Quote:

Originally Posted by Hit Man X

YES, it helps quite a bit off a dead stop performance. Search for me as the thread starter. You'll have pictures, info, testing, etc.

I looked up your thread, here it is.
ALDA tweak complete - 300SDL

I have a couple of questions.

1- What is the black plastic thing to the left of the ALDA? On mine the collar at the base is broken and it looks like fuel is leaking from there. I would love to fix it!

2- On the engine you show in the photos what do you clean to restore power like the way you clean the banjo bolt on an earlier engine?

3- How do you adjust the ALDA without removing the intake manifold?

Thanks,
Jim

Jadavis · #13 05-16-2006, 08:36 PM

This is a cross post from where I posted on another thread:

Man, the history and tribal knowledge on this site is crazy! The injector cleaner I would have thought of, but the rest of the fixes were way past what I would have figured out.

I patched the broken line with a piece of vacuum line and a couple of hose clamps. (See the post above.)

The info from some of the other threads showed me where everything was.

Yesterday I changed the air cleaner.

Today I took out the overboost protection solenoid/relay. It was plugged solid. I cleaned it out with brake cleaner and reattached it to the firewall.

I cleaned out the barb fitting on the intake manifold. It was plugged solid. I cleaned it out with brake cleaner also.

I ran a hose directly from the intake manifold to the ALDA. I ran it around the parking lot a few times and didn't notice anything.

I took out the main fuel filter, then filled the new one with SeaFoam injector cleaner and installed it. The rest of the can went into the fuel tank.

It still was only running 25 second 0-60's for the first few runs. On about the 4th or 5th run I noticed that I was getting close to 60, it was no where near 25 seconds, and there was a HUGE cloud of black smoke behind me! After about 3 more runs I was down to 10-12 second 0-60's.

I think that the injectors were dirty and the ALDA was stuck from not being used for so long. Between it poping free and the injector cleaner life is good!!!

The boost doesn't really start kicking in until 3000 rpm. I'm going to run it for a week or so and see if it continues to improve. After that I tap the keg on the top of the ALDA. The plastic cap is still intact.

I'll change the clear prefilter tomorrow. It looks clean, but I've changed everything else so I might as well change it also.

I think I'll take the old owner for a spin in his old slow as heck car. (I've had it for less than a week! )

I was so happy with it working I had to come back and edit this to mention a new problem. When I turned the key off the rpms went down but the car did not die. I'll take a look where I was working and see if I can find a loose vacuum line. I must have bumped one loose.

-Jim

(Now for a few key words so that people searching can find this easier. 300D 300DT 1987 ALDA Overboost protection relay solenoid over boost banjo bolt slug no power dog no turbo no boost piece of junk)

bfdiesel · #14 05-18-2006, 06:47 PM

Sorry for getting on your thread. I have a MB 300D 1985 with similar sluggish problems. Could you tell me what is the ALDA and where is it located.

SD Blue · #15 05-18-2006, 11:43 PM

The Alda is located on the Injection pump. It has a boost line (looks like a large vacuum line) attached to it. Here is a pretty good desscription, with photos:
http://engine.articles.mbz.org/diesel/alda/