Do modern cars still go open loop at WOT?

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Nov 24, 2003
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I know back even just a few years ago, when you modified a car slightly, you really only had to tune it at full throttle. Under part throttle applications, the closed loop control between the MAF sensor and the O2 sensor would keep things in check. You really only had to concentrate your tuning at full throttle, because that is where the engine would go to open loop, and if your mods allowed the A/F to get out of whack, then you were not getting the most of them, or at worst, could cause damage...

So I know there are still gains to be had with custom tuning around extracting the most power, and drivability, but the question is with tighter and tighter emissions regulations, do cars still go open loop when at WOT?
 
Where in the emissions cycle do cars run WOT? if they don't you got your answer...

My experience was they still did, but it could depend on the manufacturer of course.
 
With modern wideband oxygen sensors, they are using the O2 sensor at all times, except for the first couple minutes after a cold start while the sensors get up to temp.
Exactly this. Back in my early 20's (fast and the furious days) we used to do all sort of crazy car mods. Once put a turbo into a 1.9L Saturn, that application required a wideband O2. Now 'days most all modern cars have them.

My $20 ELM327 knock-off bluetooth scan tool (with IOS app) tells me whether the car is running in open-loop or closed loop. My older cars still go into open-loop at WOT. It also tells me when the ECU cuts fuel (usually on deceleration), a mode when the ECU isn't in closed OR open loop.
 
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