Can Anyone Tell Me What This "Eng Timing" Switch Is For??

it might be helpfull if you tell the rest off us what brand and type off truck that is.

 

You might try PM'ing a member by the name Autocar as I believe he own the same truck. you can find him in the flat bedder section.

 

Cummins engine looks like a 444...usally cummins are tan

 

Not a total expert on cummins but it looks like a switch to control the MVP [mechanical variable timming] so when at an idle you could speed up the timming for idle quality. MVP was used in the 80's to ###### timming under a load to try and keep cyl pressure down and give some life to the engine. The switch i do not think came standard i think that was added to eliminate the factory controlls.

 

I remember old russian trucks. they used similar switch to disable injection timing advance when engine fails to start with pre injection (usually when it is cold outdoors and batteries are low) and to avoid pinging when you drive up a hill, rpm drops and you cant downshift in time.

really it is for old school drivers.