When I go down a hill and the car is in gear with less than 3k rpm my injector duty reads 0.0% and my water temps drop rapidly. If I go down the same hill without the car being in neutral temps stay the same and injector reading is 3.4%. I saw someone who posted this is called "clean burn" what is this and is it normal.

 

Mine does the same. At freeway speeds, when coasting, mine goes to 0.0 injector duty as well. It happens when you're totally off the throttle. I guess its because at roll, you take the load off the motor. Vacuum goes up to maybe 550mm

BTW at idle, my injector duty is around 5.5

 

Yep, the ECU cuts fuel to the injectors when there's no load on the motor - it's totally normal.

Dale

 

What would cause the temps to drop to rapidly?

 

Engine isn't working very hard combined with the fact that the car is moving fast.

Light load on motor + lots of air moving past radiator = big temp drop

 

But isnt an idle a light load as well.

 

You don't have air moving past the radiator at idle, the car is just heat soaking......

 

I do when I go down that same hill at idle in neutral. But the temps dont drop like they do when in gear.

 

It's called deceleration pump (as opposed to the acceleration pump). When you take your foot off the gas, and there is no load on the engine (in neutral), the ecu nearly cuts off fuel completely.
If you are able to see the injector duty, I'm guessing you have a PFC or some other stand alone? Look up Accel and Decel function in the help file or the manual, it should explain everything.
As for the temp drop, smaller combustion (less than idle) = less heat generated.

 

Sorry to steal the thread but on primaries what kind of duty cycles do you see at 1500 and 2000 RPM? Thanks