[Vwdiesel] Mercedes 300SD questions?

[Sandy Cameron]

At 03:46 AM 10/19/2009 -0700, William J Toensing wrote:
>Went to Benzworld.com & after writing a question, was told I would have to
pay for the answer. As I previously mentioned, I traded my 1986 Jetta diesel
for a 1983 M Benz 300SD which has been converted to run on waste vegetable
oil. I got a new battery & diluted the WVO with 10 gallons of ULSD but it
still won't start. I am suspecting that the prior owner overheated the
engine & blew a head gasket although the engine still turns over as if it
has good compression. I plan to take a compression reading. I would guess it
should read around 400 psi like my VWs, is anyone out there an expert on
Mercedes diesels? Anything else like clogged injectors. The WVO system has
heaters on the injector lines to heat up the WVO. Guess I should check to
see if the glow plugs are getting 12 volts before pulling the glow plugs or
injectors for a compression check. 

Bill, I once owned a 1968  200D (for 20 years) , and the glow plugs were low
voltage and connected in SERIES. failure of one turned them all off at the
same time. Like old fashioned Christmas tree lights.

The "buss" wire would be made up of short lengths of exposed bare wire with
looped ends between each plug, and connected by the Teutonically clever
assembly of ceramic bushings, washers, and a knurled knut, passing through
each plug in series, on its way to ground at the last plug.

Not sure if the later ones were the same.

Quickest way to test is to connect a heavy wire to battery + and with a 50
amp meter in series, touch to the plug where the feed wire is connected.

No current? one or more plugs are open.

In mine, they were an exposed wire loop that projected in to the injector
pre-combustion chamber.

Sandy