I purchased an 87 300d this weekend. It has 300K on it and has a couple of issues.

1. its low on power, in the Cummins world we called it deadpedal. Doesn't even smoke good if I stomp on it.

2. Shifts funny 1-2 hard and the other two shifts are like mush.

Was reading through the Steve Brotherton writeup on vaccum and found that an aneroid attached to the governor might be causing these issues by not telling the IP that there is boost and thus not getting the needed fuel. Also saw some other posts about climate controls leaking and causing issues. How do I plug them and the EGR off for testing?

Thanks, Jim

Welcome to the forum.

Read through this thread and educate yourself on the "ALDA". My suggestion, though unorthodox, is to remove it and plug the supply line. The difference in performance is astounding:

ALDA removal........OM603


With regard to the shifting issues, you'll need to get a vacuum gauge or a Mityvac to monitor and/or adjust the transmission vacuum. Note, however, that you can firm up all shifts, or soften all shifts, but you can't soften the 1-2 and firm the 2-3 and 3-4 without transmission modifications.

There is lots of info on this engine and all of it's quirks. Use the search function and you will start seeing lots of threads with GSXR as the author. He also has a writeup on what to look for on your 1987 300D turbo. There are also several other experts on that engine that frequent this forum. Your engine is an OM603.960.

These engines have been known to crack heads, but there was a poll done here a few months ago and the cracked heads were in the minority.

__________________
Doug

1987 300TD x 3
2005 E320CDI

superior info already, going to check out some of the suggestions.... Hope that laserjet has a fresh toner in it :-)

so I ordered the primary and secondary fuel filters to rule them out.

I've been looking at all the stuff on here and I'm quite honestly a little overwhelmed. So I need to ask a couple of dumb questions to clarify things.

Looks like I'll need a mityvac to do propper testing, where do I buy one?

I've read a ton on the ADLA and I see that some want to just remove it and others insist that propper adjustment is the real answer. What is a baseline propper adjustment for it? All I know about diesels is that you can seriously alter your power with the Injection Pump and turning a few screws.

Will the mityvac act as a boost guage also so I can test the turbocharger?

Looks like the vaccum map on the 603.960 is pretty simple. Am I missing something?

I purchased the same manual as is online in CD form but its not as nice as my helms was for my Hondas.

You can get a MityVac from Sears thought that's not necessarily the cheapest place to get it. Harbor Frieght is pretty cheap (in all senses of the word) and they have unbranded units for pocket change. Make sure the one you get has a gauge unless you have a separate vacuum gauge. It's also useful to have a relief/pressure port with a nipple. Some have a hole you can't connect a hose to.

You'll have to decide if you want a metal case or plastic case MityVac. I have one of each. I can't say one works better or has lasted longer.

The MityVacs I have don't have a pressure gauge so I can't use them to check turbo output. Besides, the engine has to be under load for the turbo to generate boost. The spec calls for checking in gear at WOT at 4000 rpm or something like that.

The proper way to set the ALDA is with the IP on a bench. A good enough way is to break the seal on top of the ALDA and turn the adjustment screw until you just get smoke when accelerating. On a 603 you can remove the ALDA altogether but the experts here disagree on the consequences.

When you've read enough to decide that EGR and ARV are not for you then the only vacuum needs are the key switch, ACC and transmission modulator. The cold shift modulator takes up most of the plumbing. Don't be surprised by big black lines that go nowhere. Those are vacuum system vents.

Sixto
93 300SD

For ALDA adjustment, I forgot to mention DaveM's way of fitting a shim between the ALDA and IP. Same effect as relaxing the setting using the adjustment screws but you can do it without pulling the intake manifold.

Pull off the ALDA and see if there's an improvement in how your car runs. That will help you decide what needs attention. Whether you put it back or keep it off is up to you but I would get the car running right with the ALDA on before experimenting with it off. I'm only proposing this shortcut for diagnostic purposes.

Sixto
93 300SD

Lots of visuals at www.w124performance.com/images

Sixto
93 300SD

I'll start with fuel filters and a fresh tank of fuel, then I'll plug off vacuum to the climate control and get me a mityvac, see if I can't trace the problem down. Might just put on a boost guage and a EGT guage. Any convenient kits for those guages specific to Mercedes or should I just look to some of the performance diesel places that I get stuff for my Diesel trucks?

i have all the extra guages on my truck too for when i tow 10000 lb loaded trailers but they are superflous on a car like ours with high mileage save your money for the tranny rebuild after you have elimanated the cheap easy scenarios

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commercial fisherman diesel in my blood in my boats trucks and Dear old Dad has had me drivin them since i got my first license in 1968
1986 300 SDL 427654
1999 Chevy Crew Cab Dually 225423
1986 300 SDL 287000 Dad's
1987 190 Turbo 158000 Mom's (my inheritance)