What happens during engine braking (when a car decelerates in gear)
 

What do fuel injectors do, when you take your foot off the gas pedal, and let the car to decelerate in gear? The injectors will



1) Inject as much fuel as when idling?

2) Not inject any amounts of fuel?



How about engine oil pump? Is it turned by the crankcase pulley, so that it's speed is proportional to the RPM? Or it is controlled by the PCM?

As far as fuel:

on manual cars at least, most will stop injecting fuel as you engine brake. I swear I could hear when it stopped on my elantra due to its exhaust, but it could have been other stuff going on. The tone changed just a bit after the clutch engaged and my foot was off the gas.



The oil pump being attached to the crank will continue to pump oil relative to engine rpm. The only way the ecu could control it would be some sort of relief valve, but I sort of want oil flowing when I engine brake. Pistons spinning around at speed need oil just like when they are getting hit with controlled explosions.

The RD platform engine computer would cut fuel entirely off at zero throttle >1800ish RPM, I imagine new cars still do the same.

The Gen Coupe still injects idle fuel. The FI duty cycle is never 0%. You still get good braking and my AF gage goes full lean at +20.0.