PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

Closed Loop Question

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Old Apr 5, 2004 | 07:23 PM
  #1  
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Default Closed Loop Question

True or False ???

When I run the car closed loop it makes all fueling decisions purely based on the MAF and MAP.

When in open loop it add's the 02's into the mix.
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Old Apr 5, 2004 | 09:02 PM
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Closed loop - feed back from the O2 sensors. It acts as a feedback mechanism so it's called closed loop.


Open loop - No O2 sensors therefore no feedback.

FWIW.
joel
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Old Apr 5, 2004 | 09:27 PM
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Also, according to gameover's link in the sticky above, closed loop is not solely based on maf, because the maf doesn't respond fast enough in transitions.

To summarise:
1. High RPM behavior is totally based on MAF
2. Mid RPM behaviour has an allowance on Steady MAP behaviour before it switches to Unsteady MAP
3. Low RPM behaviour (where the bulk of the fuel cells are) is dictated by unsteady MAP behaviour that is still mostly dominated by the MAF input with small tweaking from SD)
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Old Apr 5, 2004 | 09:43 PM
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thanks everyone.

so now I know my wacky fueling issue is not based on the 02's because the behavior is the same in open or closed loop driving.

I know it's not the tuning because the tune works in another car.

so I guess now it's time to swap MAF's and see if I have one that is failing on me.
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Old Apr 5, 2004 | 10:14 PM
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At WOT the O2s are just along for the ride,
embedded reporters. In closed loop, they
try to make the news.
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