89shithatch

wrong. it isnt cut 100 percent. think about it, at idle, you engine is still delivered fuel.

t_cel_t

yeah but think about when your rolling down the road, the weight of the car keeps the engine turning.
my reasoning for this is the engine has no difference in sound or feel when i am coasting and then turn the key off and back on.

leed

In a OBD0 and 1 Honda, all fuel is cut during decel conditions. You guys are over complicating this.

Slo_crx1

I agree 100% lol. Even my Evo cuts off fuel when I'm decelerating and off the throttle, it's normal so don't even worry about it. The timing get's pulled back so far anyway that for all practical purposes it should be firing on the downstroke anyway. The only time fuel cut is harsh is when it's used as a limiter when rpms are rising at full throttle, such as the "safe guard" that my Evo has for overboost...thank god I can raise that up

0b00st0

That had no bearing in this conversation. You are only confusing people.

Like I said before:

No fuel, no combustions events, normal or abnormal.

Walter

so when engine is in decel conditions, not fuel, not spark even? only turns crank/rod and pistons up&down just w/ little air? or how it works then ? i say with little air cuz the cams are still working, i'd not say there isnt any % air on intake.

Chris Harris

yes, the distributor still sparks in decel...

the cams move, the valves open and if you are in gear you are doing what is sometimes called "engine breaking" because with the throttle closed...its hard for that big air pump to suck in air which is why you decelerate faster in gear

89shithatch

ehh kind of. real engine braking systems is the jax brakes. they hold the exhaust valves open so that the vehicle cannot spark (diesel) which slows down your wheels dramatically. if you are just in gear the engine bracking effect is much less because you are still igniting fuel.

0b00st0

Completely false. The reason why the Jacob Brakes work is because when you open the exhaust valve on the compression stroke, the engine is pumping twice as much air. Ie every revolution, instead of every other revolution.

Walter

i see , so just spark is working without nothing in cylinders (just spark)? i was wondering for instance when dyno a car, car is decelering, theoretically there isnt should be to have any gas exhaust going out through exhaust, right? because engine just move without nothing in cylinders but i would not say that's right exactly.. or yes?

i always had this doubt but i thought just engine "idle" even when u decelerate, i means there is still fuel,little air with spark...