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Old 12-10-2004, 07:17 AM   #1
happasaiyan
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Default UTEC Q: does UTEC intercept stock O2 sensor readings?

i know the UTEC can read what the stock O2 sensor says, but can it intercept that value? ie- can the UTEC report back to the stock ecu and say "yep, everything is running at 14.7:1 AFR?"

the reason for this post: my previously tuned out hesitation is back with winter gas! this is the OLF -> CLF hesitation. it seems the UTEC and the stock ecu are bickering about fuelling. as we all know by now, the stock ecu is still "changing its fuel trims" while the utec is already in OLF. the idea is that if the UTEC CAN report kosher values back to the ecu, we wouldnt get this fighting issue if the while the UTEC was in OLF and the stock ecu wasnt, the UTEC reported a 14.7:1 AFR back to the stock ecu. thanks in advance for your replies...
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Old 12-10-2004, 09:28 AM   #2
RiftsWRX
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Hmmmm novel concept... SHOULD work too... But how would you word the logic for something like that?

I'd imagine you'd want some form of "window" for this...

Though.... you know Jason... theoretically... if the US STI cuts over to it's own open loop at say 39% TPS (WRX for example is >3900RPM OR 69% TPS), you could set your x-over at 39% and theoretically it work perfectly... only thing you'd want to do is make sure your boost map is set to ECU control up until the next rounded up number... so... 0-30% would be ECU.

Jorge (RiftsWRX)
www.ProjectWRX.com
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Old 12-10-2004, 10:18 AM   #3
hippy
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Depending on what maf voltage, rpm, and a/f ratio the utec tells the ecu the engine's running, the fuel trims will still change(or not if the utec does this all perfectly). I'd think the utec would have to be able to view the fuel trims and know what you're shooting for to be able to do this correctly.

peace
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Old 12-10-2004, 10:42 AM   #4
ride5000
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to add to jorge's comment, i have an 03 wrx ecu (no open loop delay) so i've set my crossover to 65%. i run open loop fueling. there is NEVER a hesitation at the crossover point, because by the time the utec takes the reins the oem ecu has already gone open loop itself.

for those with the delay, this isn't an option.. but if you DON'T have the delay, i highly suggest it as an alternative.

ken
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Old 12-10-2004, 11:35 AM   #5
Jon [in CT]
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The UTEC doesn't understand the front A/F sensor's signal and it's unlikely it'll ever be able to modify it in any useful way that wouldn't also trigger a CEL.
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Old 12-10-2004, 11:45 AM   #6
RiftsWRX
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But it understands it enough to display it (at least on the WRX's).

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Old 12-10-2004, 12:29 PM   #7
SlideWRX
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I was under the impression that it queried the ECU as to the Lamba value.

Tom
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