In a message dated 6/22/2004 4:31:09 PM Eastern Daylight Time, firmware@TDS.NET writes: Modern diesels have an electrical device as part of the mechanical injector pump. IIRC it requires current to allow the motor to run (interrupt the current they shut down) On older (before computers) diesels it was common to have a large butterfly valve to close the intake (air) for manual shutdown. Putting valves on the high pressure side of the injector pump would be *real* bad, the pump is a positive displacement type mechanically geared to the motor, the pressure will rise until something breaks. A valve before the injector pump would be a bad idea. The fuel is used as a lubricant in the pump, running it dry would not tend enhance it's lifespan. Plus you'd have to prime the injector pump again every time (a notoriously difficult process) In modern computer controlled diesels I think interrupting the fuel would cause a fault condition, but that might only be a matter of a check engine light. I don't believe interrupting the electric line to the injector pump would cause a problem, that's how the key controls the motor anyway. Would this be an automotive engine or something else (pump, generator, etc)? -Denny > Hi all > > Does anyone know the normal method used to cut-out a diesel engine. > If mechanical only, I presume a valve needs to be retrofitted on the high > pressure side, > and if modern electric, is it OK to just interrupt the solenoid power, or > will this cause the enginer management to go wonky? > > Regards > Roland Jollivet > > -- > http://www.piclist.com hint: The PICList is archived three different > ways. See http://www.piclist.com/#archives for details. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details. When I was a mechanic for some fleet companies, we used mostly Cummins diesels with a few Detroit and Caterpillar engines. On a Cummins they actually have a solenoid valve that shuts off the fuel supply to the injector pump. On Detroits it is a mechanical fuel injector linkage that shuts off the fuel to the injectors. On newer engines they will use a computer controlled shut down system. It has been a number of years since I worked on those so I don't know the details of how they do it now. Although, my brother-in-law has a '97 Dodge 2500 with a Cummins engine in it and they still have the solenoid valve on the injector pump. Of course the overall operation of the engine is controlled by a computer. Regarding having to prime the engine, you would only have to do that if you let the tank and filters run out of fuel. Not if the injector rail runs out of fuel. Since there is a return line from the injector rail it usually is almost empty anyway when not running, at least there is air in there until the pump starts back up. Randy Abernathy 4626 Old Stilesboro Road NW Acworth, GA 30101-4066 Phone / Fax: 770-974-5295 Cell: 678-772-4113 E-mail: Cnc002@aol.com I furnish technical support, repair, and other related services for your industrial woodworking machinery. My background as Senior Service Engineer for the SCMI Group for nearly fifteen years with factory training, combines with my extensive background in electronics, mechanics, pneumatics, electrical and CNC machinery to offer you needed support for your machinery. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.