True function of the glowplug.

lmorris · February 8, 2011

Up until taking the 6.7L diesel course, I assumed the glowplug heated the air in the cylinder. During the course it was shown to us that the 6.7L uses the glowplug to ignite the fuel and not heat the air.

I bring this up because that was the only question I got wrong on the diesel theory test on this site.

Discuss......

mchan68 · February 8, 2011

So does that mean we can sell eight new glow plugs RETAIL as a 6.7L Diesel Tune-Up Posted Image ?

lmorris · February 8, 2011

Only for cold start performance. Posted Image

Bruce Amacker · February 8, 2011

They've been spraying fuel on the tip of the glowplug for ignition for a long time. It obviously does both, but it's a trick question to word it as only to ignite the fuel.

I'd complain to FMC and see if they'll change your score.

Posted Image

Keith Browning · February 8, 2011

I beleive they changed that wording with the 6.4L training. It caught my eye as well and if we dig the forum here it may also have been mentioned.

Subsequently the DTS quiz you took is old. In fact, the updated version will be loaded with the new DTS website and will actually reflect this change.

I have always thought heating the air in the combustion chamber was the function of a glow plug as that is what I was taught loooong ago. Bruce's statement that fuel being sprayed onto glow plugs for ignition is new to me and it makes sense. If we banter this around enough and find some supporting documentation I would even consider changing the answer on the quiz to "both."

Time for some searching. Great topic!