Dear friends:

Since diesel engines do not use spark plugs, I wonder whether it's true that a diesel car (e.g. an old one without any computer-controlled emission/timing etc..., and no lights) would continue to run until it is out of fuel even if its battery and alternator are completely dead.

If it is, it's a great advantage of a diesel car hehe.

Eric

Once my alternator died in Manhattan and I had to drive someone home to Queens. When I got to Queens, my voltimeter showed 11.5 volts while running. Bad, but not terrible. I turned all the devices off except for the lights. By the time I got to Westchester (about a 25 mile drive), I had virtually NOTHING. My lights were probably glowing a bit, but definitely not projecting. I'm really glad I didn't run across any police, they surely would have pulled me over and I'd have to explain (although maybe they would have escorted me home). Point is, I had a dead alternator and dead battery and made it home. The car was still running like a champ.

I ordered a voltage regulator from FastLane, replaced it myself in a few minutes two days later and everything was cured. Great car.

Alex

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1983 300D (parked for four years)
2012 VW Sportwagen TDI Manual
2001 Miata SE
1962 Chevrolet Corvair Rampside

Yeah same thing happened to me, dead battery, dead alternator. I still made it home

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2008 BMW 335i Coupe

There are only 2 ways to stop a diesel. Starve it of air. or stop the fuel flow to the injection pump. this is exectly how Mercedes stops the diesels they shut the fuel off to the injection pump.

The same way with Aircraft piston engines. The spark is a magneto which is self contained so to stop the engine we cut off the fuel. (We can also cut of the ignition, but we don't stop it that way). In a jet engine we HAVE to cut off the fuel. That is the only way to stop a turbine engine.

Dave

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1970 220D, owned 1980-1990
1980 240D, owned 1990-1992
1982 300TD, owned 1992-1993
1986 300SDL, owned 1993-2004
1999 E300, owned 1999-2003
1982 300TD, 213,880mi, owned since Nov 18, 1991- Aug 4, 2010 SOLD
1988 560SL, 100,000mi, owned since 1995
1965 Mustang Fastback Mileage Unknown(My sons)
1983 240D, 176,000mi (My daughers) owned since 2004
2007 Honda Accord EX-L I4 auto, the new daily driver
1985 300D 264,000mi Son's new daily driver.(sold)
2008 Hyundai Tiberon. Daughters new car

Yeah, I had a dying Alternator one time.

Only way I found out was the starter just didn't want to crank fast until it jsut stopped cranking altogether

Luckly there was a Sears across the street where I got a new battery and drove the car home.

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2005 Audi A4 1.8T CVT -Silver/Black "Siegfried"

1982 300D - Silver/Blue "Ralph" -For Sale:
http://www.peachparts.com/shopforum/showthread.php?p=852260

1989 VW Diesel Jetta Blue/Blue "Bodo" RIP

I might hold the record: I made it home from Alasks to PA with a dead alternator in a '80 300SD. I had a battery charger with me so every night I charged the battery and that was enough to keep the engine running all the next day.

It got a little dim in Billings Montana when it started getting dark and the headlights looked like candles, but the engine ran the same as ever.

So yes the mechanical injection Diesels will run without electrical energy once started but the newer electronic injection and computer controlled will not. That sounds to me for like a vote for mechanical fuel injection.

P E H

PEH, I think your record is safe...
What year did they start making the ones which will not keep going without electricity ?

I would think the OM603 in 1986. I know my 99 wouldn't have a prayer of running with a dead battery. But it does everything so nicely that I don't mind keeping a battery and alternator in it.

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Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
Chain Elongation References

Leather,

I don't know what year but I would think anyone without a mechanical injection pump.

P E H

I know this thread is as dead as a doorknob, but I just recently had my alternator go bad at the beginning of a 2 hour trip in my 1987 300TD, with the OM603.

At the end of the trip, I turned the car off in a parking lot, and it wouldn't even crank over when I tried starting it when I came back. This proves the OM603 can still run without a battery

The above is true but how do you get the engine to start to begin with? The other part of it is do you need to use the glow plugs to get the engine started. If that is so you at least need enough battery for that.

If you have a manual transmission, you might be able to push your Car jump in and get it started. Pushed or drag started.

If you have an automatic transmission, it has been claimed it can be pushed or dragged by another vehicle up to lie 30 mph and you have a chance to start it.

Many Diesel Engines have air starters to crank the engine.

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84 300D, 82 Volvo 244Gl Diesel

It actually has the instructions in the owners manual on how to start with the automatic transmission being pulled by a vehicle. Have done it. It works.

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'83 SD, 2x '85 SD
You are entitled to your own opinions, you are not entitled to your own facts.

Yeah I remember the manuals of our previous W123 diesels and there are instructions for that. Never tried though, always just started with jumper cables if needed.

Have had dead batteries and alternators in W123 and W124 diesels lots of times and they will run till you run out of fuel.

Last month my son was stranded with a dead battery in his 240. I drove the 300 to him, removed its battery while it was running, and put it in his car to start it. I then put his dead battery in the already running 300 and charged it on the drive home.

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1985 300 TD 448K
1984 300 TD 278K

1983 240D euro 240k
1994 f-250 idi turbo 330K
1986 f-350 IDI
1987 F-350 IDI

1985 JD 1050 4wd
1965 IH 3660

I love the cigarette lighter voltmeter/usb chargers. Years ago the voltage regulator on my 300cd went bad. I knew it because of poor voltage output. I was 150 miles away, warm weather. I managed to do the drive with minimal HVAC, and drove without headlights where possible (just parking marker lights). Barely made it, not because the car couldn’t run - it would run as long as it had fuel, but instead because of illumination…

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Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)