Mountainman wrote:
I think GDE said to use the Bosch 5v only. FWIW
Actually GDE doesn't recommend any specific plug afaik, Mountainman.
GDE checked the factory 7v programming and found it ridiculously insufficient, so they wrote their own tune for people that want to stay with 7v metal plugs, and their tune is all they recommend. If I understood their post, the Bosch metal 7v plugs are the only ones they tested it with.
Sergio. One more time. The
"time on" duration of the
glow plug LIGHT has
no relationship whatsoever
with the
"time on" duration of the
GLOW PLUGS.
Both are controlled - separately - by the ECM. I know the FSM shows a chart indicating that it's dependent, it may have been the FCA intention, but in all actuality, it's really not.
However, what IS true, is the "Glow plug power ON" from time of ignition ON.
Coolant . . Pre-heat . . Post-heat
-30C . . . .35 SEC. . . .200 SEC.
-10C . . . .23 SEC. . . .180 SEC.
+10C . . . .21 SEC. . . .160 SEC.
+30C . . . .20 SEC. . . .140 SEC.
+40C . . . .19 SEC. . . . .70 SEC.
+70C . . . .16 SEC. . . . .20 SEC.
I removed the "light time" column as it has no accuracy.
You can see, though, that both pre-cranking GP heat time, and post-cranking heat time are scaled by coolant temperature.
Essentially, whatever the glow plugs you use, Tune being equal, the 5v plugs will get hotter than the 7v plugs.
Other than that, the only difference required between a little bit cold and very cold, is TIME. Give them more time to warm their environment up. Some will turn the ignition on, but not crank for 20ish seconds, then off, then on again for about the same time, before cranking to start. Other than that, I guess keep it plugged in, but unless it's on a timer, it can get expensive.