PeachParts Mercedes-Benz Forum - View Single Post - revelation about "only clicks when starting hot engine" problem

Jeremy5848 · #3 12-15-2008, 01:43 PM

Quote:

Originally Posted by kerry

Glow plugs are de-energized when you move the key to the 'start' position so that should not be an issue unless your issue is a problem in the system which is stopping the glow plugs from being de-energized at times.

No, the glow plugs are de-energized when you release the key from the starting position. The FSM says "If the key is turned to position "3" (start), the power relay (a) remains retracted, activated by terminal 50. The glowing process is continued until the key is returned to position "2". [Source: Service Manual, Diesel Engines 602, 603 by Mercedes-Benz of North America, 1990.]

Caveat: some earlier Mercedes diesel engines may have a different pre-glow relay that does not work in that manner.

Unfortunately, this puts me in the position of disagreeing with Toronto's statement. If the car has recently been driven (and therefore has a "hot" engine), it should have a fully charged battery. So there should not be a problem unless the battery is old/weak. Therefore, I am puzzled by what is causing a hard-starting problem that is fixed by waiting a few seconds after turning the key to position "2."

Jeremy