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TurboDiesel newbie

4K views 40 replies 11 participants last post by  Captain Caveman 
#1 · (Edited)
Ok.. I bought this '83 300SD very recently. Neat car, but it's not in great shape. Depending on how things go with it I'll fix 'er up some, or if it starts being a money hole we'll make a beater out of it.

Radio is broke, seat switches are destroyed, the injectors likely need refreshing or the pump looked at (it smokes), etc... You guys might be stuck with me awhile. :D


My door locks cycle non-stop.. lock... unlock... lock... unlock.. until the battery goes flat. Gah. Not fun, so I unplugged the vac pump. heh

Sadly, I don't have a knack for search terms, but yes I will continue to work with that.

Does anyone have a thought or idea about the door locks?

oh - Thanks!

-CC
 
#2 ·
The switches for the power locks are located in each front door, and in the trunk. They're actuated by the key locks. Perhaps you can't get the key to work in one of those? I'd start there. One could be jammed up somehow.


As for smoking and things like that, the injection pumps seldom require any kind of service. Unless it was abused with some concoction of improperly heated artery clogging waste fryer oil, the pump should be fine.

Compression check the engine with it warmed up. You'll want to wear gloves! You want to see numbers in excess of 300PSI (bare minimum) for an engine that will run well. They can actually run smoothly with worse compression than that, but will never really run correctly. You don't want to see a deviation of more than 20PSI across each of the five cylinders, as a rule. Unbalance will cause poor running.

There are many filters. If you have not yet, change them. Two in the engine compartment, and a screen in the tank itself.

Inspect the entire fuel system for leaks, as air in the system can cause undesirable running. The manual primer on the lift pump is a common source of trouble if it's leaking.

After that, search 'diesel purge.' It will help you clean your injectors without removing them from the vehicle, and can actually help with the smoke.

If that doesn't work, remove the injectors and take them to a local diesel repair shop- it's typically inexpensive to have them cleaned and pop tested.

Once your fuel system is in good order, the car will run a lot better, and you can focus on the other things.
 
#3 ·
+1

All good stuff - on the compression tests, get the numbers for before and after valve adjustment. Leaky fuel return lines can be a source of air in the system, not to mention fuel/oil leaks. Clean airfilter - if the existing one is soaked with oil that won't help...remove the oil filler cap an see how much blowby there is when hot...
 
#8 ·
Ack. My compression gauge only goes to 300psi.

Lesse... I have a box of motorcycle specific stuff, a box of 4x4 stuff, a box of engine stuff (ODB and Ford EEC readers, *gas* compression gauge, re-ring tools, etc..), a box of machinist stuff, box of fabrication things, box of..... y'all get the picture.

I need another box. For diesel stuff. Gah.

:D
 
#9 ·
I appears I have two seeping injectors.. and one that actually leaks enough to pool a little fuel in the injector to nozzle threads.. it's "smell-able" with the hood closed.

I's very tempted to go through these myself, clean and freshen them up some... A reasonably mechanically inclined fellow can handle this, yes?
 
#10 ·
First replace the braided jumper lines. When these fail, it's a small leak that runs down the injector giving you a false sense of where the leak is.

Do use new heat shields as mentioned.

Have the injectors tested, no need to replace anything that is fine.

If you do take the injectors apart, pay close attention to how it came apart, there are shim/s and a spring. They must go back in the same order and same direction.

Also, you'll need to lap the joints, make them as flat as possible so no leak can occur. There is no seal ring there.
 
#11 · (Edited)
Parts ordered: role of return fuel line, 10 injector heat shields, and a few oddities....

Looking for a local that can test the injectors, plus scanning pick-n-pulls for interior switches and panels.

After reviewing how the injectors go together, going through them doesn't seem to be a big deal really.. patience and delicate handling of parts comes natural to me. :)

It seems my journey has begun, there goes a box of nitrile gloves.... heh

You know it was weird... most of the local parts houses can get injectors, but not heat shields. I asked why they do that, if the shield is required to change an injector?
 
#12 ·
CC,
If you have a Car Quest Auto Parts store nearby, they use WorldPac and can get most anything, within reason. and they use MB part numbers as a rule. Just don't buy any Uro/ADA rubber bits, as stated before, they are junk and you woill redo the job in 6 mo or less.
Good luck with your new ride.
BTW I have Shown rabbits at the Fairground in Shelbyville. I'm a transplanted Hoosier.
 
#13 ·
CC,
If you have a Car Quest Auto Parts store nearby, they use WorldPac and can get most anything, within reason. and they use MB part numbers as a rule. Just don't buy any Uro/ADA rubber bits, as stated before, they are junk and you woill redo the job in 6 mo or less.
Good luck with your new ride.
Actually, yes... I DO have a CQ in shelbyville.. forgot all about that. Thanks!

BTW I have Shown rabbits at the Fairground in Shelbyville. I'm a transplanted Hoosier.
I assume you mean the four legged kind? :)

Pretty cool!
 
#14 ·
Yepper $ legged. Netherland Dwarfs. Actually won a best of Show the last time I was there. That was in the early 90's.
 
#16 ·
Anyway....

Took the SD out for a drive today, after replacing fuel return lines. The amount of fuel evident around the injectors went down markedly! Still have a little smell tho, it needs more attention.

Drives very good! The tranny shifts are a bit sluggish and late sometimes, and the engine doesn't shut off unless the brake is depressed. Odd, but ok I'll figure that out with better diagrams of the pneumatics I hope.
There's a little noise in the right front suspension... steering, braking, etc. all seem great, time to inspect that too.
Fluids/filter changes are on the agenda, and a peek at the valves. (.004/.014 IIRC)

One of the wood panels on the rear driver side was separated from the aluminum, I sprayed some 3M adhesive on it and wrapped it firmly in shrink wrap until it set. It worked! lol (the wood already had a crack in it, I'll live with that)

The body is rougher than I thought.. well the whole car is really.. which makes it great to learn all the particulars for a SD! :)

This thing is enjoyable to drive. I thinks I likes it.
 
#17 ·
Today.... went over some stuff, re-installed a door panel that was off when I got it. Found several MORE items to repair.
Added to the list: right rear window problems, fuel gauge is fruity, vacuum leak in the dash somewhere, drivers headlight adjustment links are broken.... sigh....
On the upside, once this car is squared away, I'll know ALL about it. :)
 
#18 ·
this is the best way to learn about your car
 
#20 ·
sounds like you've got a good amount on your hands! But from what I've read you seem to be off to a good start.

This might be helpful too, Mercedes posted up all the service manuals for the 80/90s vintage cars. Here's yours:
Untitled Document
 
#21 ·
Thanks for the kind words JD!
 
#24 ·
Been making a few more drives i the ol girl. It rained on the way home from work this morning... and I gotta say, windshield wipers are pretty cool! :)

In process of accumulating more parts, gonna try to make a weekend out of it. Hopefully with these things in mind (in order):
valve adjust
tranny fluid/filter
front suspension inspection
dash work (heater, inst. lights, cig lighter)
seat controls

Will it ever end? lol
 
#25 ·
Will it ever end? lol
The SD's are a resilient bunch. My green one has gone strong for a number of years, only needing basic maintenance stuff.

Just today I flushed out the power steering system. Prior to that it was groaning something awful. Not any more it seems. I had to replace some fuel lines as well. Not bad IMO. Got 24 mpg at fill up today.
 
#26 ·
Congrats on the SD. I'm about a year in and its a love hate!! My tip is catch Macco on the half off single coat with gloss ($500). pay for the quickie body work. Important: pick a light color cause every wave from maaco wil show. however....I can drive the bucket down the street without being picked on cause its a combination of parts from 6 Junk yards. When you are all set for th the $4000 professional body shop paint job (in year 5 of your resto)....maaco will be ready to come off.
 
#27 ·
more kind words.. thanks folks, I need it. lol

...

CarQuest! them guys got parts! valve cover and injector heat shields came in same day as ordered. Sweet! although.. it appears I may not use the heat shields for awhile.
 
#28 ·
Did a valve adjust today, and it sure did need it. I used plain strait wrenches... and I see what the fuss is about the "special wrenches" for the job, they sure woulda been nice!

I think the is the first time I've ever adjusted valves that lost clearance due to usage.
That's a testament to MB cam and follower design..

..

Seat switches came in, as well as tach amps (I got spares!).. ElRojo is the man.
He did inform me about a seat switch difference (Gen2 to Gen1), but I'm charging ahead on that tomorrow I hope.
Seat switch thread here (with some good diagrams):
http://www.benzworld.org/forums/w126-s-se-sec-sel-sd/1649003-seat-controls-gen2-gen1.html

Tach amps seem to try and work properly, the tach does act weird though, so I suspect the crank pickup needs some attention.

I guess this thread is turning into a "build" thread of sorts, but it's more bringing a beater back from the brink than anything. :D
 
#29 ·
Fixed the dash lights today. Removed the rheostat, observed a wasted coil and corrosion in there and soldered/bypassed the thing.
Oddly, the dash lights are about right and not too bright at all. :)

Plus, I think this is my first try with the autoguide app. Nice!

Sent from my Droid using AutoGuide.Com Free App
 
#30 ·
Keep it up CC....these are GREAT cars and worth the effort. I've had my SD a little over 5 years now and still love it. You're right about the dash lights though. I had new put in my 400E and had vastly better visibility on the gauges....putting the SD in the shop this coming Monday for a few odds and ends and new dash bulbs are on the list...
 
#31 ·
Alas, my solder job seems to have failed - the dash lights quit again. *grumble*

Dash lights became secondary however, when the ignition tumbler failed and ceased to function. *major grumble*

So, it's out to the car a few minutes at a time every day, try the key in the ignition, hoping for that one time it turns to the 1 o'clock position.. and remove that sucker.

In a week, failing all other options.. it'll be a forced extraction (not looking forward to that!).
 
#34 ·
Haven't been on in awhile, figured I'd check in.

My ignition tumbler turned one day, I removed it and flushed it with cleaner.. and it does work. It won't be in there long however, and I did discover that removing the "key" that holds it in place means I can get it out when/if it fails again. heh

Sadly, I'm not having much time to fool with the car. The new gal in my life is on my mind more than the Benz... and frankly I *really* should have waited for a better opportunity on a 300SD. The more I look, the more I find wrong with the ol' gal (the car, not the GF!).

I really like this car, but it needs a lot of work.

Also, it appears to have some grounding issues. Opening the sunroof makes the tach jump all over for example. Weird but true lol.

Been thinking about alt. fuels lately. I'm such a stickler for things, WMO or WVO would have to be virtually perfect for me to run it.. meaning it's probably not worth it for me.

Today, we'll get some work done on it and see how it goes. This car is going to eat my wallet alive if I don't pour tons of elbow grease in it. :)
 
#35 ·
Well, after a hiatus from the Benz, I'm back to fixing the thing up some.

The heater control had several bad solder joints in it, the aux. water pump sticks sometimes (a sharp tap with an extension gets it going), and the monovalve is getting a kit this week lol.

Fixed some issues with the passenger door not latching correctly, and been chasing power seat gremlins (like the disconnected motors, for example). Fixed the dash lights again, and some other doo-dads.

Next up, a diesel purge and some underhood stuff....

I love driving this old car. Man it's addictive. :)
 
#36 ·
Better replace the Aux water pump, because it will fry your ACC controls if it goes bad and it sounds like it is headed that way.
 
#37 ·
I was thinking of installing an inline fuse holder to it permanently (one amp?), to forever prevent that. It'll be unplugged until it's fixed. :(
 
#39 ·
Well, I've taken a different route I guess, and still fixing the old gal up.

Fortunately, most things so far have been more labor than anything.

It is ugly tho. heh

Couple Pics Here
 
#40 ·
I figured out that if I start the car, set the heat for what I want, then get out and tap the monovalve, it works until I shut the car off. :-/

Next up, speakers and tranny service...
 
#41 ·
Monovalve is installed! If you park the rear end of the car uphill, little if any coolant is lost. :)

Since I installed a radio, bypassed the fader etc.. .. my cigar lighter quit. heh
 
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