My 81 300D won't start! About 3 days ago (exactly coinciding with our first snowfall and freeze) my old battery died completely. It is a bad battery, will not recharge fully, etc. So, after trying to recharge the battery and start the car, I bought a new battery. Much better turning over, but it still won't start.

I checked my haynes manual and did a careful search of these archives but nothing seems to be "clicking" as what might be the answer.

I unpluged the glowplug relay (in the little black box in the corner of the fender - Thanks Larry Bible) and checked all the plugs for continuity - every single one of them have have continuity with the ground. Is this right? If not - why would all the glowplugs go wrong at once?

The metal fuse bar is good.
I didn't have any real problems starting it before.
Suspect that there might be something wrong with my vacuum as it was beginning to delay shutting off for a few seconds after turning off the switch.

One other thing that may help you all help me. When installing the battery, I didn't have it all the way in and it touched the bonnet and made a hissing and left a small circle of clean melted metal on the bonnet. Battery seems to work fine, but would that have had an impact on the glowplugs, etc.

THanks for your help,


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81 300D 250K+ (odo doesn't work!)
Want another one.

Thanks,

You may be right. My hand pump (the old unscrew kind.) leaks like crazy, I don't know if it is pumping anywhere besides on the ground. But when I tried to pump it and then start it, it changed the tenor of the engine. IT still won't start, but at least it sounds like it wants to.

What are my other options? Where is this fuel shut off valve, can I replace that?

I would like to get it started so I can go get some parts. I am stuck at home now.

Ultimately is my solution to replace the vaccuum pump or the fuel pump?

Thanks,
Josh



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81 300D 250K+ (odo doesn't work!)
Want another one.

Josh,

I sincerely hope you don't get into the level of problems that I'm having with my daughters '81 300D. I'm sure you won't.

Have you put a voltmeter on the glowplug connector to ensure that they are getting voltage? In the past I have had very good luck by screwing in all new glow plugs, when the car gets to this point.

I think your next step should be to check the voltage at the glow plugs. If the voltage is there, next pull a glow plug or two.

Just because the glow plugs have continuity, doesn't mean that they are good. I have seen holes burned in the shell of these type plugs.

Good luck, and keep us posted, we'll get you through it somehow,

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Larry Bible
'01 C Class, Six Speed
'84 Euro 240D, manual, 533K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

Josh, are you sure that your fuel filter isn't frozen up? Spin it off and see if there is ice inside. Also, you could have air in your injector lines since your hand pump is leaking. Just a quess from 700 miles away.LOL Good luck, Jay

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Thanks to all who helped here. I am have a better idea, but I still haven't got it working.

Per your advice Jay, I checked the fuel filter - full and over flowing. No ice there either.

Per LarryBible, I am in the middle of replacing the glow plugs. I have them all out, but cannot find a store open today (Holiday weekend and all) which carries them. THe dealership is closed and everyone else has to special order them and their warehouses are closed until monday.)

TXBill,
I have tried to pull the throttle control a little and start it. I used to have to gas it a little as it started as it had a hard time starting first thing in the morning. But so far no luck.

Did a search for Glowplugs in the archives. Turned up someone who had the same problem and he fixed it by changing all the Glow plugs out. I will try that next.

One more question - how do you know if the plugs are bad? I have the new pin type.

Josh


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81 300D 250K+ (odo doesn't work!)
Want another one.

You have been given a lot of good advice on getting your car started. The only thing I can add is to be sure you have pure diesel fuel.I have seen quite a few times where the owner will fill up with gas, drive home and the next mornihg the car won't start.
Now about your odometer not working.I have instructions on how to repair MB odometers. They are fairly simple,and no special tools are required.If you want me to, I can scan them and send them to you. There is one page of instructions and one page of pictures. Just let me know and I'll be glad to do it.
Bill Lewallen

Bill,

Thanks, I would like the instructions for odometer repair. You can send it to nunezj@exec.state.mi.us.

You know, I have replaced the glow plugs, checked the fuel, and now I am doubting about the gas/diesel question. I am 99.999999 percent positive that I put diesel in it. I have been driving a borrowed gas car since Tues. but before that, I never, ever bought gas. I can't imagine me being so stupid that I bought the wrong fuel.

I guess I will do a smell test, but I just can't imagine me doing that...

Thanks,
Josh

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81 300D 250K+ (odo doesn't work!)
Want another one.

OK, Time for an update and a prayer for more help.

I have eliminated the Glow plugs - checked voltage (OK), bought new ones and installed them.

And the glow plug relay - dome-light dims when turn the key to switch position 2.

And the fuel question - unscrewed the fuel filter and smelled it. Definitely diesel.

Now it is on to the vaccum shut off valve. Any advice for this step?

Any more diagnostics? I have learned much about this car from this forum and the last few days of working on it, but I would like to know just a little more. Like why it won't start. Tried a freshly charged battery tonight. Cranks wonderfully, no catch.

It is late so we will resume tomorrow. i will let you know.

Josh


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81 300D 250K+ (odo doesn't work!)
Want another one.

Josh,

I hate that you're having so much trouble, I sure hope you don't have as much as I do on my daughters car.

Is your compression okay? Your cylinders should be making near 300PSI each.

Good luck,

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Larry Bible
'01 C Class, Six Speed
'84 Euro 240D, manual, 533K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

This may be ridiculous but, have you tried plugging it in overnight? My '79 300SD will not start if I do not plug it in overnight and the weather is 32 or lower. I would also make sure your hand pump is o.k., no air in your system, and maybe some anti-gel in the fuel system.
Have you manually bled the fuel system with the hand pump, until no more air comes out?

Patsy,
I have been pluging it in. But recently the temperatures warmed to +35 and still no spark of life.

Larry, I have thought about the compression - I assume that I have some problems there - engine is burning oil about 2 quarts every 1500 miles. But would that cause it suddenly not to start - remember that I drove it to where it was without any hint of this problem. But since I do need to check them, how do I do it? Through the glow plugs or through the injectors (which I need to replace as they leak.)?

I am convinced that the problem is in the fuel delivery. I have power to the glowplugs (11 volts), relay is working fine, I can hear the click and can see the cessation of current to the glow plugs.

I need some advice about the vaccuum shut off valve. I have a plastic housing of some sort on top of the fuel injector pump with two vaccuum hoses going to it, a metal thingamagig that looks like a bicycle bell with a nipple going off to the side that is NOT connected to any hose, and a short round cylinder on the back side that also has a vaccuum hose running to it. Which one is the shut off valve?

In the alternative, can you tow an automatic in neutral about 3 miles if you go slow? i have heard that it is not good on the automatic transmission to tow it in Neutral.

It has been a week now and I am driving my father's volvo four banger that is not firing on one cylinder. If you thought diesels were slow - try driving this. I miss my Benz.

Josh

__________________
81 300D 250K (sold)
79 240D 200k
83 Volvo Station Wagon (282k)

How strong is your starter?

"I need some advice about the vaccuum shut off valve. I have a plastic housing of some sort on top of the fuel injector pump with two vaccuum hoses going to it, a metal thingamagig that looks like a bicycle bell with a nipple going off to the side that is NOT connected to any hose, and a short round cylinder on the back side that also has a vaccuum hose running to it. Which one is the shut off valve?"

The "short round cylinder on the back side" sounds like your shut off valve. The white plastic housing is your vacuum control valve. The "bicycle bell" is the ALDA housing

Sorry to revive this old thread. I had an awful week full of root canals, offers and counteroffers on houses, and other things.

Anyway, I am going to replace the hand pump as it leaks. Then I should be able to pump some fuel to ensure that it gets in the chamber.

If nothing happens tonight, I will be hiring a tow truck to take it to a respectable shop in Lansing. I am frustrated and defeated by this car. I still wnat to buy another one in better shape, so I haven't given up on Mercedes, just rather frustrated with this one.

My thanks goes out to all those who helped me with advice and suggestions. I have learned a lot that I will apply to my next 123 series Mercedes.

Josh

P.S. I will post the final solution in a new thread when I know something.

__________________
81 300D 250K (sold)
79 240D 200k
83 Volvo Station Wagon (282k)

Josh, here's an idea to see if your engine is getting fuel. Remove one of the glowplugs and crank the engine. I'm sure you will be able to tell if any fuel is being delivered.

Gary