I guess it is just a personality issue. My first go to resource is myself (I am a reclusive parson that seldom speaks to people). Also I sometimes pass on information to other forum members and if I could say you can lift the hood and look at something and easily tell if the update was inplace think that would be a good thing.

Fortunately I have a Federal Car without the evil device on it so I don't need to identify mine.

I have owned my Mercedes for 12 years and I have never called the Mercedes dealer.

Don't know if it is the same now but in the Past the Long Beach Mercedes dealer had a lot of poor feed back on the Internet. A week ago my Wife drove buy the Long Beach Mercedes dealer and she said a few people were picking against it and it was not a labor dispute.

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84 300D, 82 Volvo 244Gl Diesel

I have not read of a way to test the overboost protection valve.

My personal view:
The exhaust gas pressure and flow turns the tubo which intern compresses the air when it turns fast enough to do that. The increased manifold pressure causes the ALDA to give more Fuel.

When you go say up hill the combustion pressure in the cylinder rises and creates a higher flow and pressure of exhaust gas as explained eventually causes a an even higher manifold pressure in which again the ALDA allows more fuel. Kind of a circular issue.

If you are towing a trailer up a steep hill the combustion pressure in the cylinders is going to shoot up and your exhaust flow and pressure will shoot up and since you are sort of lugging the engine you don't want the extra manifold pressure causing more fuel to be delivered. What you need to do is down shift. Anyway in that situation the overboost protection valve cuts off/reduces the manifold pressure/signal to the ALDA and keeps it allowing more fuel.

While the wastegate is supposed to open and bypass the turbo and dump off some exhaust gasses to keep the manifold pressure in check apparently Mercedes felt the need for a back up or perhaps there is some odd situation where the wastegate cannot bypass enough exhaust gas to protect the Engine from being over fueled.

In normal driving you could actually just run a hose straight to the ALDA as some in the past have done and you will have no safety issues. If it seems like you are lugging the Engine switch down to a lower gear if the Transmission does not do that for you.

If you tow a trailer having the overboost pressure switch connected would be a good idea.

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84 300D, 82 Volvo 244Gl Diesel

I definitely recommend the the Monark brand primer pump. Then, you could remove the electric pump that is in there. I got mine from mercedes source. It came with good instructions. I think they are even cheaper on eBay.

I’m an introvert, too. I checked the receipt (from 12/20/1996) and it lists MB part no. 126-490-34-14 for the “oxidation catalyst.” I checked under the hood and the part number is visible on the side of the device. So I would think this would be a way to check without having to phone the dealership.

The letter I received from MB before I took the car in to have the work performed says, in part, “we are happy to inform you that we now have a replacement device (for the trap oxidizer) with sufficient durability, therefore replacements of the trap oxidizer will no longer be necessary.”

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Christopher
'06 Mercedes E350 station wagon (silver/black)
'85 Mercedes 300D (black pearl/palomino)
'85 Mercedes 300SD (smoke silver/burgundy)
'79 Cadillac Sedan DeVille

'05 Toyota Camry (because always running is nice)

'85 Mercedes 300D sold back to orig. owner 8-1-06
'84 Volvo 264GL Diesel, owned 2000-2013

I have a 1985 CA. The original "trap oxidizer" is dull cast-iron. The replacement (forgot name) has a shiny stainless cover. It is more like a catalytic converter (honeycomb ceramic). Rollguy here sells a "test pipe" which replaces it. If you still have the OE, M-B will still replace it for free, I understand.

The blue saucer is good and they continued that 1986+. I added one to my 1984. It is basically a vacuum amplifier for the VCV "signal" to the transmission, plus adds a few features for acceleration.

Your emissions controls likely no longer work and no new parts available. There is a diagram posted many times which shows what parts you can remove, which will clean up ~1/2 of the vacuum stuff in the bay. You can also remove the EGR valve with plates Rollguy sells (~$15). After that, plus rerouting the AC h.p. run, I can now loosen the alternator bolts in 5 min instead of an hour of cussing.

People fuss that the CA air filter is $45 if you can find one. I just stack 2 cheaper filters (Wix 46070), for 1985 Toyota MR2. Others have the air filter housing above the intake manifold on a bracket which shakes & breaks. I added the 1985 air filter to my 1984.

The electric fuel pump will work. However you provide it, the injection pump needs >10 psig at its inlet. I assume the lift pump is still bolted to the block, beside the IP. If the housing is OK, it should be easily rebuildable since the design is common to most Bosch lift pumps and kits are ~$15 (ebay). Indeed, I wondered about adapting another Bosch pump but most have the ports facing in ways that would bump into components in the engine bay. If yours still has the OE white plastic primer pump, lose that for the smaller & better black one (many posts, white one sucks in air).

To check boost, I just tee in a vacuum/boost gage to the tube off the intake and clip it under the windshield wiper to view as I drive, or when more motivated, ran a tube thru the rubber grommet into the cabin. You should see ~10 psig under hard pedal as the engine rpm increases. Don't goose it up or you risk melting pistons.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

Lots and lots of mechanical diesel gensets use engines not unlike the OM61x. Many get a boost pump added in order to provide sufficient flow through a fine filter and water separator, and give both lift (often these gensets are mounted on top of the fuel tank) and extra pressure. Works like a charm.

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Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (116k)
1991 350SD (206k)
1991 300D (228k)
2008 ML320 CDI (199k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (267k)

Past Diesels:
1983 300D (228K), 1985 300D (233K), 1993 300D 2.5T (338k), 1993 300SD (291k)

Hey guys!

This blew up. Thank you so much! All of this is great info for sure.

I did clean the banjo bolt off the intake. Turns out, it's missing a washer haha. So I have to get one of those. I also cleaned the crud outnof the aneroid.

Embarrassingly, that was the cigar hose. It was all cracked so I replaced it with regular hose (stupid of me, I know).

But! I do have parts coming in tomorrow. The cigar hose is one of those parts. Broke the vacuum line from the pump to the brake booster too.

I did hook a gauge up to the threaded port on the intake and the turbo is creating 5 psi- 11 psi. The only thing is I'm not sure if the ALDA is increasing fuel delivery. Any way to test that?

I plan on changing the fuel filters, along with a purge and cleaning the gas tank ( after removing the fuel level sensor, it was apparent there was a lot of crap as my gauge did not work very well) and monark nozzles. This lifter pump, I'm not really understanding very well. How can I test this? And this is what the electric pump might be trying to replace?

As for the air filter, I just ordered a new one as AutoZone sells them for $90 and had no way to get one. But the current one is FILTHY.

I have a lot to learn on this andni appreciate everyone's help. I just want to feel better about the car for my wife.

I've still got the steering slop to take care of, cleaning and replacing fuel filters and doing a proper job of hooking up the vacuum.

You know what really grinds my gears though? Some jabroni butchered the front doors and rear deck lid to install speakers. I took them out because they couldn't even get it right man..

Again, you all are incredible. Thank you so much!