85 300sd wont start when cold
85 300sd wont start when cold
Super Member
Joined: Dec 2009
Posts: 541
Likes: 22
From: USA
10 speed bicycle
Did you test them with an amp meter? The glow plugs are PTC's(positive temperature coefficient) which means as temperature goes up so does resistance. If you use an inductive amp clamp to check them each glow plug should start at about 20 amps and taper off as they heat up, cause if resistance goes up and voltage stays constant, current flow will decrease(Ohm's law). The amp test is more of a dynamic test. Also where did you check for voltage, at the relay or the individual glow plugs?
Junior Member
Joined: Jul 2009
Posts: 39
Likes: 0
From: Surrey BC Canada
82 mb 300sd, 85 mb 300sd, 96 Niva, 80 300sd parts car
How cold? I recently solved this problem when advised to count to thirty after GP light goes off. Starts every time at -10C with out block heater plugged in.
