New 1983 300D Turbo
 

What's up. Just bought a 1983 Mercedes 300D with a Turbo.302k on the odometer and it runs. Needs pretty much everything, previous owner did not take care of it. New battery. I have new glow plugs for it and it supposedly has a new glow plug relay, but the glow plugs in there don't work. The dash light GP symbol does not correlate to the glow plugs I don't think so though. Anyways, I will post some pictures up later! Oh btw I paid $500 for it. It does run amazing though.

Troubleshooting glow plugs is pretty easy.

What should happen is:

Turn key to "run"
Glow plug light illuminates
Glow plug light shuts off
The engine should now be able to start

The relay energizes when the key is turned to the run position. The relay provides current until either the key is turned to "start" and released back to "run", or the timer times out the relay after ~1 minute.

You have parallel glow plugs, so if one is dead the others will still work.

If you put the key to "run", wait 10 seconds, crank the engine, and it starts within 5 seconds of cranking, at least the glow plugs have some function.

Anyway, we'll need more info from you to diagnose further.

Lot of basics to do.
New set of copper/bronze fuses
ALL fluids and filter changes
Adjust your valves.
Fluids include your radiator.

You have a GP relay on the drivers side fender. They very seldom go bad.

Welcome to the forum!
And remember ... the only stupid question is the one you dont ask

Good advise so far.

The relay has a fuse too, remove and inspect carefully, they are know to obtain a hair line crack.

I posted a pic of the location in post #14 here:
http://www.peachparts.com/shopforum/diesel-discussion/365934-well-my-240d-glow-plugs-failed-morning.html

Welcome aboard, Rookie! Lots of great advice on here, not much from me. My M-B Diesel is in an S-10 race truck that's pretty stripped down so the Mercedes body, suspension, and brake stuff I haven't dealt with. The good news is that there are guys who have and they're willing to share their experiences without a lot of ego - good folks!

My glow plug system is really basic, using a continuous duty Ford starter relay so it doesn't apply to your situation.

I have done some serious engine work (new crank seals and main bearings, new turbo, new injectors, etc) so I'll chime in if I actually know something. Otherwise I turn you over the the experts.

Dan

Ok thanks for the tips guy. They are very welcome. So I found out that my glow plug relay is full of water.. How that happened I have no clue. I assume the previous owner is responsible. It would make sense that the glow plugs are burning out. Well that and they are the crappy auto lite ones. I have another question though. The transmission on this will shift without the key in or brake pedal held down... Any clues on how to fix it??? It is almost an electrical mess, but I am slowly but surely figuring it out. My sunroof ain't working either. I am waiting on parts for a brake caliper rebuild for all. Unless somebody has all 4 for sale and they are in good condition lol. Thanks guys!!!

The bit about the shifter moving in and out of gear without a key in the ignition or the brake pedal pressed isn't an issue.. that's just how it works. No shift interlock in these caars.

BTW, as advice from someone who bought a basketcase 300D and eventually parted it out: go around the car and tally all the costs that you will incur bringing it back to whatever state you are trying to get it to. Then, look at what cars in that condition are going for. You may find that you can spend quite a bit less money in the end by buying a nicer one and keeping this thing as a parts car.

Oh, and don't worry about not getting "repair experience" from a $2000-$3000 300D, if that's what you are trying to do with this car. Any 30-year-old car will definitely give you that.

I appreciate the advice. Yeah I bought her as a fixer upper. My daily driver is a 2013 F350 6.7L Diesel. Part of finding everything that's wrong is half the fun!! I tried searching but is there a symbol table??? Like what everything means?? The doors have some kind of electric lock but I don't see a button for it. Once again thank you for all the help

The doors have vacuum locks :). They are operated by the plungers -- there are no buttons. I don't exactly remember which plunger operates all doors (I think it's only the driver's plunger), but I do think that both exterior door locks operate all plungers... I've never had a 'Benz with working central locking, so I'm guessing what I think I remember reading in the owner's manual.

Speaking of which do you have an owner's manual for the car? If not, I may be able to dig up one to send to you... it may not be the exact year, but not much changed for your car between 1982-1985 that would be reflected in the owner's manual.

Yeah no owners manual at all. I have a half rigged diesel maintenance manual lol.

Oh, and nice truck, dude! How is the 6.7 stacking up so far?

Even if you keep the car and fix it up, I would still make a full inventory of what needs to be replaced. Can't hurt, and that way you can plan everything out.

I think you can get old repair manuals for the car through STARTEK, a website on which Mercedes publishes repair manuals for older models. If they ask for a credit card number, they aren't going to charge you anything, they are just doing that to confirm where you live.

As far as an owner's manual, I have a decent 1983 240D/300D/300CD Owner's Manual sitting next to me. It's yours if you want it -- just PM me a mailing address. It's handy for educating yourself on how all the features in your car are supposed to work.

Ok, so I was poking around my engine just looking at what to tackle next. I stumbled upon the ALDA and what looks to be an upgraded switchover valve. The line that goes off the ALDA is just chilling and not connected to anything. The switchover valve looks to be hooked up to the automatic transmission valve thing next to the ALDA. The Banjo bolt line is connected to the switchover valve. Also when I took the banjo bolt out to clean it, it was covered in black OIL and soot. I figured out the Glow Plug issue for those are didn't catch it above.

Anybody ever create a simpler linkage system? Anyways, once again thank you for the advice and help.

Ok, so I have started tackling unbolting pieces from the engine, yet I am stuck. If somebody can show me a video or something how to get the turbo, exhaust off. Do I have to take everything off in pieces? Because I have everything loose and it still feels like something is holding it on there. I unbolted the turbo drain pipe from the bottom as well, trans dipstick, banjo bolt and line to switchover valve, air filter assembly, etc. Any help would be great.

Ok pretty big update for you guys. I will post pictures later....I am bad at that, yet know from my long time internet forum membership(2002 on the first one) that pictures run the interwebs. Anyways, here is a list of everything done;

Turbo rebuild including new shaft
Valve Cover Gasket(Did not adjust valves, I have some homemade wrenches, but I couldn't get it figured out, will attempt at a later date)
Exhaust Manifold Gasket
Temperature Sensor(One by the glow plugs)
New Glow Plug Relay(Old one got water in it and was badly corroded)
New Glow Plugs
Re-routing and deleting of Vacuum lines(Car vacuum door locks and associated systems have been removed completely; leaving only the Transmission, climate control, ALDA, and the bolt on the backend of the exhaust)
Emergency Brakes replaced(Car would move before with the shifter in neutral even with the E-brake applied
Brake Calipers all around rebuilt(Car came with Bendix, but at some point the passenger rear got switched out with ATE
New brake hose from hardline to brake caliper
New Tires are on the way(Going with Michelin Defenders)
Fuel Filters(Primary and Plastic filter)
Oil Filter
Transmission Pan Gasket and Filter
Oil Pan Gasket
Oil Change
Transmission Fluid Change
Powersteering fluid and filter change
Thermostat with rubber gasket and paper gasket


I still need to go buy coolant for it, as it has green coolant in it and rust in it. I presume a flush will be needed too. I also have numerous other gaskets, o rings, etc that once we complete our move to Louisiana, I will rebuild almost everything on the engine with the exception of the Injection Pump, Transmission, and bottom end of the motor. I have new freeze plugs, valve seals, in the process of buying all the different valves, etc. Not looking to make this a really nice car, but a solid commuter. As far as interior goes, I need to find a backseat, and get the fronts and backs re-up holstered with either leather or cloth(Haven't decided). I am gonna do some sort of sound blocking/all weather liner that will limit the noise that gets into the inside. New Stereo, with speakers and bluetooth system for phone calls.

It's been great learning everything on these engines and how simple they really are. The turbo was pretty easy to rebuild and I really learned a lot from doing it. The next MAJOR thing will be getting the whole electrical system unscrewed. Basically nothing really works as far as the switches, windows, or sunroof. If anybody has any recommendations, I am all ears.

P.S. My idle speed its right at or below 1000 rpms. What can I do to try to adjust it?? Rack Damper Bolt? Idle screw in between the block and injection pump??

Holy cow....that is some good work! Like, 80% of your list I still need to do to my W123, and I keep putting it off...

Nice man!

As far as the electrical system goes....Check the basics first, and check the fusebox that is under the hood on the drivers side. Some people have reported difficulties getting the lid off, since you need to kinda twist it to get it out. I personally never have had a problem, it's pretty damn straight forward.
Anyway, check your fuses. They should be copper. In most of these cars they have been replaced with metal ones at some point, and the metal corrodes the fuse box and introduces all kinds of nasty electric gremlins.

The solution? Buy all copper fuses (you can get them on this website, they are dirt-cheap), throw away all the old ones and sand the contact points on the fuse-box lightly, to get rid of the corrosion.

The attachment shows how to adjust the idle.

Ditto on fuses. When my windows or sunroof stop working, I know to go straight to the fuses. One tip-off is that one fuse supplies diagonal windows. I remove, sand the ends, re-install w/ silicone grease on the tips. Eventually, I'll replace all the tin ones w/ gold ones.

Also, the #8 fuse (cabin blower) likes to melt the plastic. If yours isn't melted yet, it likely will. I traced the problem in my 1985 300D to a bad factory crimp under the fuse-holder that gets high resistance, thus heat. I soldered across it, plus powered the blower relay box via 30A relay straight from the battery (search for my post).

You can quickly check glow-plugs from the connector at the GP Relay Box, using an ohmmeter to BATT-. Should be <100 ohm. The dash lamp isn't sufficient since requires ~3 GP's to be open before it warns you.

I believe the above poster has misplaced a couple of zeros.

Yes and no. It would be silly to get hung up on the exact resistance measurement. It is more of a binary measurement (yes/no). If bad, you will read infinity. If good, you will read less resistance than your ohm-meter can resolve. I said <100 ohm because simple. Always short DMM leads to get a "zero", which might be 5 ohm on some. Then you have wiring and "poor contact" resistance.

If really interested, there are many details to a simple resistance heater. They can short internally so it gets hot in the middle, not at the tip where you want it. You would have to look down the injector hole or test one in the air to see that. The cold resistance just verifies continuity. As it heats up, the resistance greatly increases. If you calculated expected power (P=V^2/R) from the cold resistance, you would get an unreasonably high value. Ditto for an incandescent light bulb.

Thanks for the clarification.

Whats up guys!!! Overdue for a update!!! This forum is a great resource and I appreciate everybody's input. To those who posted and I didn't get back to you, I'll explain.

To recap, I bought this car for $500 and I did not hear it running and had to tow it home on a trailer. It was a Montana car, but luckily had been taken care of as far as the exterior is concerned. The bottom has undercoating on it, and there are only 2-3 spots of LIGHT rust. Other then that, everything is solid. I got that joker home(I was in Washington State at the time) and did the things I said above. I drove it around the corner and stuff like that, but never really took a trip with it. So I get stationed in Louisiana, have to pay more then I paid for the car to tow it here with us. I didn't end up getting the Michelin Defenders, but I got the Champiro GT Radials for it. So I have been starting the car up every week just to make sure that nothing sits for too long and everything keeps moving and gets lubricated. I also want to add that I have no exhaust at this point, because the exhaust to downpipe connector piece broke and I haven't been able to find another one. So that being said, I am driving the car full time now and love it....except that fact that my engine bay is black and sooty from no exhaust. If ANYBODY has one of the connector pieces that I can connect a downpipe to please let me know!!! I should add that I have the Garret T3 Turbo.

Stuff that I have done in addition to the above things:
Changed out all the lightbulbs in the dome lights with LEDs
New Lightbulbs for my climate control module.
Soldered a jumper wire on the back of the rheostat so I can see my instrument cluster in the dark.

Things that I need to do:
Rebuild my injectors
My Tachometer rarely works, it's very intermittent
Speedometer Bounces
Coolant Flush, Fill
Repair my cruise control, It does not work AT all.
Replace the Windshield
Replace windshield wiper fluid motor and Lines
Get Exhaust
Find a back seat(PO sold the backseat before I bought it.
All Engine mounts, Flex Mounts,
New Shocks
Front end Rebuild


http://s13.postimg.org/w8oi5faib/Mercedes.jpg

http://s13.postimg.org/k87nifshf/Mercedes_2.jpg

That list will keep you busy for a while.

The tach is probably the amp, under hood near the glow plug relay, a common failure item.

Same issue, perhaps with the CC, that amp is located under the dash on the steering column.

Good luck with the exhaust.

An old diesel trick with an exhaust fume issue. Leave the windows up and the blower running full blast. Also those fumes are both carcenegetic and can make you sick otherwise. I have never driven a 123 with an exhaust issue but suspect the same rules may apply.

Ok, cool, Thanks Toomany, I will pull the CC amp tonight and see what I can do with it. I think the tachometer AMP I will just try to replace, they seem to be a bit cheaper. I found the part number of the exhaust piece. Craziness is how much it costs, I am gonna make something will work, but is cheaper and MUCH easier to find. I was under the car and there is a plug that seems to plug into something, but I can't find it. The plug is cone shaped almost.

A local muffler shop may be able to help, as opposed to the pricey MB part.

Pics of the mystery plug? Location?

I believe there is a poster here that does amp work.

Yes, forum member JamesDean will rebuild your cruise control amp for (I think) $60. Or maybe it is $100. Either way, it's a great deal. That's on my list for the next few months.

When it stops raining, I will take a picture of the plug. I pulled my CC AMP last night and it was flawless. Somebody just replaced it before I bought the car. I am not an electrical engineer by trade, by I did go to school for it. Everything was brand new inside, and now I think I know why the CC was unplugged when I bought the car. I suspect it is the actuator, or perhaps the stalk now. I have the actuator out and am in the process of taking it apart to see what the inside looks like. Plus it won't hurt to clean up the metal a little.

As far as the stupid Turbo to Downpipe Connection piece, I am trying to fabricate something that is much easier and uses 1 piece instead of 5 or 6. I found a SPOTLESS and perfect interior door panel on Ebay for only $50 and it's in the Palomino that I need for my passenger side. I am pretty pumped for it to get here!

JamesDean just did my W123 cruise control amp for $70 + $6 shipping. I got it back on Saturday and popped it in. Works perfectly now. Quick and friendly service too, so I recommend him.

Yeah, My AMP is perfectly fine and good to go. My actuator is the problem. I broke it down tonight, and it is completely corroded inside. It's not even worth it for me to try and clean it. The only parts that I'm salvaging are the plastic gears, steel shaft, and the outside case. So I am on the lookout for a new actuator.