Wide open throttle closed loop operation with a wide band o2 sensor?
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Wide open throttle closed loop operation with a wide band o2 sensor?
I was reading a book called "TPI Fuel Injection Swapper's Guide" which suggests that because a wide band o2 sensor is accurate to an 18:1 air/fuel ratio that wide open throttle closed loop operation could be possible. Apparently a conventional o2 sensor is only accurate under part throttle operation because it can only read the air/fuel mix up to 14.7:1. If this is true then theoretically the ECM would be able to adjust the air / fuel mixture for best power throughout the RPM band. My question is has anyone permanently installed a wide band o2 sensor in a TPI car to verify this?
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From: Saint Louis, Missouri
Car: 1985 Camaro IROC-Z
Engine: 383 HSR Comp XFI280HR Profiler 195s
Transmission: T5
Axle/Gears: 3.73 Posi
Re: Wide open throttle closed loop operation with a wide band o2 sensor?
I was reading a book called "TPI Fuel Injection Swapper's Guide" which suggests that because a wide band o2 sensor is accurate to an 18:1 air/fuel ratio that wide open throttle closed loop operation could be possible. Apparently a conventional o2 sensor is only accurate under part throttle operation because it can only read the air/fuel mix up to 14.7:1. If this is true then theoretically the ECM would be able to adjust the air / fuel mixture for best power throughout the RPM band. My question is has anyone permanently installed a wide band o2 sensor in a TPI car to verify this?
Well this isn't possible with stock ecm hardware. Rbob actually developed code for this type of operation for the EBL, but decided it wasn't the best route if I'm not mistaken. The problem with using a wideband for closed loop WOT is what happens if your sensor malfunctions, or you have a sudden mechanical issue that changes lambda readings? It's a recipe for disaster. The slightest problem could cause a drastic and sudden over or underfueling condition. The conventional logic of BLM modifying open loop pulsewidth (at WOT) if lean proves to be pretty practical and reliable for safe engine operation. It really is beneficial to learn the fuel map in with a wideband when the engine is operating with no problems.
Edit: just realized this post was a few years old. Oh well, the info may prove useful to someone else.
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Re: Wide open throttle closed loop operation with a wide band o2 sensor?
you dont want closed loop control at WOT typically because of the unreliability involved in the train of sensors/hardware.
It is not a robust control system and could ruin an engine
It is not a robust control system and could ruin an engine
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HoosierinWA
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Oct 7, 2015 10:15 AM