Runaway diesels

[davidkerryedwards]

Runaway diesels get discussed a fair amount on Mercedes boards because
the older MB diesels can easily runaway when a replacement shut off
valve is installed incorrectly. (and it's very easy to install it
incorrectly). One thing that was determined in a recent runaway event
was that simply pinching shut the fuel line with a vice grip or some
such device will stop the flow of fuel and shut it down by causing a
vacuum in the line as the pump tries to pull the fuel. Cutting the
line or knocking off the filter will allow the remaining fuel in the
lines/pump to keep flowing for a while as air is allowed into the
system. On an FC, I'm thinking keeping a pair of vice grips handy
under the driver's seat which could be applied to the fuel line after
raising the aft portion of the doghouse might not be a bad idea.
However, as Randy said, it takes a set of titanium balls to continue
hanging around once the engine starts running away. A very well
respected mechanic on the MB board I frequent lost an engine a couple
of years ago when it ran away. At that time, nobody seemed to think
that pinching or cutting a fuel line would be adequate and people were
advocating loosening the injector lines. That takes WAAAY too long.