Closed loop function ecotec/L67

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immortality
Posts: 3416
Joined: Thu Apr 09, 2009 12:31 pm
cars: VH, VN, VS, VX

Closed loop function ecotec/L67

Post by immortality »

Can someone please explain how the 2 timers works on the closed loop function for the ecotec/L67?

Not long ago my low speed thermofan stopped working on the missus Calais, this allowed the engine to reach much warmer temperatures than it did normally with a cooler 82°C thermostat fitted. On a recent trip down south I noticed that once I'd driven the car, let it get up to temp and then stopped the fuel economy improved, this occurred when the engine temp got much higher than normal (heat soak with the engine off). So much so that when cruising I could actually see the instant fuel usage dropping as we cruised at a constant speed/constant TPS. When I got home I checked the tune and found there are 2 timers in the closed loop function. A cold/enabling temp and timer as well as warm enable/timer. See below
L67 closed loop settings.png
I've dropped the warm temp threshold to just below the new thermostat temp which seems to have improved the function of closed loop but I'm trying to understand what these 2 timers actually do/represent.
spoolin4dayz
Posts: 4
Joined: Tue Aug 16, 2022 6:27 pm

Re: Closed loop function ecotec/L67

Post by spoolin4dayz »

I would assume that the better fuel economy was due to the higher ECT your "lean cruise enable temp" got triggered causing the car to run leaner hence less fuel use. i was data logging my turbo ecotec tonight and noticed the AFR reading 16+AFR at 5% TPS, as soon as i put a little bit more throttle down it dropped back to 14.6 AFR.

My Lean cruise enable temp was set at 85 degrees so i bumped it up to 90 coz i didnt like the AFR being that high before getting in to boost.
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