Hi all-
I recently acquired a 1987 300TD wagon with 190,000 miles. It accelerates sluggishly from a stop, but the turbo works great at higher rpm/speed. 0-60 time is 14 s. I cleaned out the pressure line from the intake and verified there is a pathway for pressure to the ALDA. Not surprisingly, vehicle performance didn't change. I have disabled the EGR and ARV (temporarily, of course), and any improvement of the accel was mild if at all. 0 to 60 time is still 14s.

I applied pressure to the ALDA and it leaks. Specifically it leaks at about 1 psi per second. I pump it to 12 psi, and it leaks down at that rate. In searching the archives, it appears that many years ago, this leakage rate was considered acceptable and not worth fixing. Is that still the consensus?

The ALDA screw is intact, but I don't know yet if it has already been shimmed. Pulling the ALDA will clearly be a next step. But if I am pulling the ALDA off to shim it, I am trying to see if I should address the leakage at the same time. If it is worthy of fixing, what is the best approach? Used ALDA's on ebay are ~$70.

As an aside, elsewhere someone recommends using a ADA washer on the ALDA (part 007603014405). Has anyone tried that part?

Many thanks.

Andrew

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1968 220D, w115, /8, OM615, Automatic transmission.
My 1987 300TD wagon was sold and my 2003 W210 E320 wagon was totaled (sheds tear).

A pressure leak at the ALDA, within reason, isn't of the slightest concern. The boost pressure is more than sufficient to overcome the leak at the rate of 1 psi/sec and the ALDA won't notice the difference.

What you will notice is the much better driveability (and possibly some increased performance) if you simply remove the ALDA and plug the boost line.

It's a little tricky to access on the 603 but two wrenches usually does the trick. You place one wrench on the bottom flats of the ALDA and the second wrench on the nut beneath the ALDA. The upper wrench should be positioned so that it is slightly clockwise (looking down) from the lower wrench. Then, squeeze the two wrenches together with one hand and the ALDA will break loose from the nut.

Your 0-60 time is not bad... a bit slow, but not terrible. It does sound like you need to adjust or shim the ALDA to improve the off-idle power.



This leakage rate is not bad. When the seal is totally shot you can't pump it up to 12psi by hand, it leaks as fast as you can squeeze the MityVac handle. I'd say the seal replacement is optional. I've got a new shaft seal I'd sell for $10 shipped if you want it.




Most likely everything is original/stock. Keep in mind that used ALDAs will probably have the same issue as yours, or worse. No point in replacing the ALDA unless something is physically broken inside. For test purposes you could go for a drive with the ALDA removed and see if there is a major change in power. If so, shimming/adjusting should cure your problem.



I don't think I've tried that particular washer, but it may fit. The bigger problem is the thickness, if it's too thick, they are difficult to file down.

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Dave
Boise, ID
Check out my website photos, documents, and movies!

Thanks Brian and Dave. When I get a chance to pop off the ALDA, it will be interesting to see the performance improvement. While I plan to use the car primarily, my wife may need it on occasion to shuttle kids around (the 3rd row seat was a major selling point for us). Assuming the car smokes significantly upon normal accelerations without the ALDA, I plan to shim it for the long-haul. She probably doesn't want to see much (any?) smoke coming from the tailpipe. As Dave pointed out, my car's accel is not bad currently. I just want it to be a little easier/safer to cross busy roads or make quick left turns across multi lane roads. I also want to keep fuel economy up, so less smoke probably helps with that. Although the jury is out (from older threads on the topic) whether mpg will suffer without ALDA.

Dave-I will think about the shaft seal. As you both say, the current leakage is okay. But "tomorrow" could be a totally different situation.

I will post a followup once I pull the ALDA. Thanks again.

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1968 220D, w115, /8, OM615, Automatic transmission.
My 1987 300TD wagon was sold and my 2003 W210 E320 wagon was totaled (sheds tear).

I accidentally drove my car for a few months with the ALDA effectively removed, loose atop the IP. Long story short, my fuel economy picked up 5-10% after the ALDA was re-installed, and the smoking at low boost was nearly eliminated. When adjusted/shimmed properly, there is no power loss, and minimal (if any) smoke.

Note that if the car has been driven gently for many years by a previous owner, it may smoke noticeably at full throttle / high RPM, but the more you drive it hard, the smoke should gradually go away (at least until you drive the car sedately for a while, which will carbon it up again). As a general rule, it's a good idea to give the car at least one full throttle blast to the redline through the first 3 gears (speed limits permitting), at least once per tank of fuel.

BTW - if the engine is in top shape with proper fuel delivery, you 0-60 time in the wagon should be roughly 12 seconds, maybe less, if you're near sea level (assuming flat road, accurate speedo, stopwatch used, etc etc). The sedan is about 1 second quicker.

Near where I live, there is a 6% grade for a few miles which I have used in my 220D to work the engine for a while at full load. I tried the same hill in the "new" 300TD, and it was impossible to drive at full load without going way too fast. It is going to take some getting used to a car with 2.5X the HP of my old one. So I appreciate your suggestion of simply doing a full throttle blast to redline. It is intimidating to drive a car up to the redline, but once I am certain the car is in decent order, it will be a good method to keep the carbon minimized. Thanks.

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1968 220D, w115, /8, OM615, Automatic transmission.
My 1987 300TD wagon was sold and my 2003 W210 E320 wagon was totaled (sheds tear).

Just to close the loop on this thread, I finally took the ALDA off today for the first time. It's adjustment screw cap was not previously removed, so I decided to shim it. I used one of the copper oil filter washers/seal-rings, as they are the right ID and OD. I didn't actually measure the thickness, but elsewhere on peachparts it was suggested that they are sufficiently thick to be equivalent to no ALDA. I wanted to try the performance of no ALDA combined with relatively stock appearance.

As you all suggested, the performance from a stop is remarkably different. Even with high expectations/hopes, I was pleasantly surprised. I was unable to see any smoke during accels, and the shifting didn't seem much different. It did smoke a little bit at idle while cold, which it didn't do previously. If that persists, I will probably put a thinner shim in. I do like the power when doing a left turn before on-coming traffic, but I also don't want my kids to smell the car when sitting at a traffic light.

I drive the car so few miles that I don't yet have a good handle on the fuel economy, so unfortunately I won't be able to share if shimming the ALDA was detrimental. Previous fuel economy has been 25-29 mpg, but that is for only 2 tanks. Also, I recently bought michelin low rolling resistance tires, so that would complicate any direct comparison to previous values. The car desperately needed tires, and the cost differential for LRR tires was small enough to justify their added expense.

My 0-60 time is now ~13 seconds, which is plenty good for me. The bottom line is the car feel safer in traffic, which is a great thing. Thanks again for all the help.

Andrew

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1968 220D, w115, /8, OM615, Automatic transmission.
My 1987 300TD wagon was sold and my 2003 W210 E320 wagon was totaled (sheds tear).

the one thing I noticed with the alda removed is the trans tends to shift itself a tad too quickly in traffic. because the pedal is not pushed as hard the bowden thinks you're at speed and shifts for economy.

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Dave and others like to run the hell out of the engine periodically to "blow the carbon out". I don't disagree with their approach, however I offer an alternate:

On the 300SD, I have used 5 oz. of PowerService for every tank. This has occurred for the past 75K miles, religiously.

The SD gets driven sedately, never past 3200 rpm unless an emergency arises, and typically runs between 2000 and 2800 rpm. Most accels are done without boost at 2000 rpm and the engine is allowed to gradually climb to 2800 for the highway.

The engine has no smoke, no carbon buildup, starts instantly at all temperatures, and gets a steady 29 mpg.

I conclude that my approach is also an option for keeping the engine from fouling itself on carbon. Since my approach is an ongoing continuous approach, rather than a hit and miss occasional approach, I prefer it.

The cost of the PowerService (about $.13 per gallon) is negligible in the grand scheme of things, and might even be free if it's contributing to the fuel economy.

Brian,
What PowerService Product do you use?
Diesel Kleen, Cetane Boost or both?
In the past, I have used Lubro Moly's Diesel Purge ala DieselGiant's method
of running on straight Purge to clean the system.
Diesel Purge Mercedes diesel maintenance tips


Jeff

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1984 300SD 300,000 miles--two tank WVO setup
2.88 diff & 500SEL anti-squat rear end

This:

DIESEL KLEEN® +Cetane Boost®: Max HP Formula ? use during non-winter months for the ultimate in performance.

If it is really cold, I'll switch to this:

http://www.powerservice.com/dfs/