Plus less wear on your braking system.

 

A wideband reading is a ratio

Air/Fuel

If you took math in high school, a high number would indicate a higher ration of air to fuel - which would mean there are more AIR then Fuel particles in the ratio.

Therefore the car is running LEAN.


It is totally normal while the transmission is under load while moving to have it stick at extremely lean.


The injectors do not turn off, they just dont put out much fuel~!

/thread

 

First the extra lean condition is normal when the engine is in a negative torque condition. Keeping this as simple as possible, in this condition the drivetrain is providing the torque to maintain engine speed.

The injectors most certainly do not fire (meaning duty cycle is zero, and ecu commands it so) when an engine in a negative load condition. The engine goes lean since there is absolutely no fuel being injected. It would be a waste to inject any fuel under this condition.

Note: With the clutch is disengaged or the transmission in neutral, the engine cannot experience a negative load condition.

 

injectors shut off and there is air flowing that is why your wideband is reading lean.
if you are cruising and you see above 16 somewhat constant, id be worried.

 

haha mine does the same the thing but i was afraid to ask. awesome news!

 

Almost.

There is still fuel going into the cylinder, due to the engine still running. It's just a weak amount that there is WAY more air going in than fuel - thus the highest reading on the wideband is displayed,

Once you get back on it, it will immediately kick in more fuel into the equation, richening the mixture, lowering the AFR on a wideband


Last time, this is normal.

 

INJECTORS DO NOT TURN OFF
if they did, your motor would not run. cars dont run on air alone.....

 

+1 yep

 

For the record, it is 100% feasible to have 100% fuel cut on decel (I am NOT saying this is the case in regarding the EVO's ecu). The road load is still giving torque to your drivetrain which is still rotating your crank. The concept would be the same when you "pop the clutch" or mechanically start an engine without a starter.

 

An engine still needs fuel to run. The injectors are still working then. It's part of the timing cycle.

 

^ LOL! The injectors do shut off. On decel the compression of the engine slows you down and the inertia of the moving vehicle keep the engine spinning. My wideband (PLX M300) reads AIR during decel. Unless Wyotech and BMW STEP are wrong, they teach that injectors shut off.

 

so if your saying i would turn my car completely off on decel, it would act exactly the same as it normally does?

what about backfiring? my car backfires a lot on decel. if there was no fuel, why would it be backfiring? just doesnt seem like theres no fuel being injected

 

Popping on decel is an indicator of a rich condition on lift off.

As others have mentioned, when you lift off the gas pedal the injectors should turn off, and yes the engine becomes an air pump until you reach conditions for closed loop fueling to resume.

 

its not just on lift off, its the whole time on decel

 

residual unburned fuel in exhaust system.