Sjd6795
Proven Member
- 614
- 121
- May 14, 2014
-
Wilsonville,
Oregon
Injector latency varies per injector and is suppose to adjust idle AFR. Does increasing latency give more or less fuel though?
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Ok that's what I had thought. I seen another post that mentioned more latency = more fuel. I knew that couldn't be correct, startup idle AFR is good on my car 14.7, but after driving a bit the idle stays around 12ish. I doubt adding more latency would change that.Latency = deadtime
more latency would = less fuel kinda ( a larger amount of time to fully open)
Let me try a different way. (not counting posting overlap) As others have stated the injector latency is "deadtime" the amount of time spent waiting for the injector to start spraying fuel after it gets a signal to do so, minus the time it takes the injector to stop spraying fuel after you tell it to stop. The ECU normally calculates from air mass flow how much fuel it needs and knowing the injector flow rates it derives an injector pulse width to which it has to add the latency so that the time actually spraying fuel equals the expected pulse width. Since latency is fixed but injector pulse width isn't the latency value has more % effect on low iPW that on high ones. (More effect at idle than WOT)
If you guess wrong and make the latency too small you with up getting less fuel than desired and if you go the other way and use a too large value the result it the injector are open longer than desired and you get a richer ratio.
MAF smoothing is intended to linearize the MAF signal with regards to the airflow. Since all fueling calculations start with the mass airflow you want the measurements to be as accurate and linear as possible. IMO, Unless you changed the MAF or modified it and have a way to calibrate it you may be messing with the wrong table for tuning the car.
Seems to be a little richer. I dont have a way to log my wideband but based on looking at it and comparing to the afrmap its richer at cruising rpm. It's also a custom big map that English racing tuned when the previous owner had the car.So how do your AFR's match up to your fuel maps?