Closed Loop Operation Calculation Issue with Fuel Trims - Continued

FlashPro questions & answers specific to the 2006-2009 (US, UK, Asia) S2000
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s2000cr
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Closed Loop Operation Calculation Issue with Fuel Trims - Continued

Post by s2000cr »

Hello,

I have 2008 S2000. At idle, when the closed loop is turned on, the AFR hunts between 12 and 15. As stated in the previous post, “The LTFT always goes deep into negative numbers trying to pull fuel. However, the STFT is trying to correct it with positive numbers. It's as if the LTFT has a mind of its own at idle and will not follow STFT numbers.” When the closed loop is off, AFR is stable around 14.6 to 14.9.

Per the previous post, Hondata stated that “The problem is that the Honda ECU always looks for the SO2, even when unplugged or disabled. I can look to see if there is an alternate way to stop the ECU using the SO2, but it might take a little while. The error condition is what stops the ECU using the SO2, not what I originally thought but useful to know in order to fix the problem.”

Please send me beta software so i can test. This will be very helpful to the S2000 community.

Thanks.
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Hondata
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Re: Closed Loop Operation Calculation Issue with Fuel Trims - Continued

Post by Hondata »

There is no test or beta software for testing.

Please provide your calibration and a datalog showing the issue.
Hondata
s2000cr
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Re: Closed Loop Operation Calculation Issue with Fuel Trims - Continued

Post by s2000cr »

Please see attached tunes and datalogs. One tune and datalog shows the secondary O2 enabled and in the other it is disabled. You can clearly see that the AFR is hunting when the secondary O2 is disabled. Also, at some points the S. trim is positive but the L. trim is negative.
Attachments
AFR stable at idle - secondary 02 sensor enabled.fpdl
(9.31 KiB) Downloaded 15 times
Tune with Secondary O2 enabled.fpcal
(10.14 KiB) Downloaded 16 times
AFR hunting at idle - secondary 02 disabled.fpdl
(21.43 KiB) Downloaded 15 times
Tune with Secondary O2 disabled.fpcal
(10.14 KiB) Downloaded 17 times
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Hondata
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Re: Closed Loop Operation Calculation Issue with Fuel Trims - Continued

Post by Hondata »

1. Datalogs were made with old software.

2. For testing live tuning needs to be disabled.

3. Is your goal to run with the s02 enabled or disabled? If disabled, then unplug the s02 and see if that changes the behavior.

4. Injector dead times look low for a 1500cc injector. Did you tune the dead times or just use manufacturer data?
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s2000cr
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Re: Closed Loop Operation Calculation Issue with Fuel Trims - Continued

Post by s2000cr »

Please see attached with datalog on the latest software. Also, live tuning is now disabled. My goal is to run the s02 disabled and plugged in. The fuel trims are normal when the s02 is disabled and plugged out. However, if the s02 is disabled and plugged in, AFR is hunting, fuel trims are high, unstable and erratic. Injectors are ID 1300cc. The dead times are tuned. What are the next steps? Will you release a beta software for testing?
Attachments
AFR stable at idle - secondary 02 disabled but plugged out.fpdl
(8.36 KiB) Downloaded 22 times
Tune with Secondary O2 disabled.fpcal
(9.98 KiB) Downloaded 20 times
AFR stable at idle - secondary 02 sensor enabled v2.fpdl
(3.48 KiB) Downloaded 18 times
Tune with Secondary O2 enabled.fpcal
(10.05 KiB) Downloaded 19 times
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Re: Closed Loop Operation Calculation Issue with Fuel Trims - Continued

Post by Hondata »

Again - there is no beta software.

How were the injector dead times tuned? The times look like they are straight off the ID website, which will not work.

Do this test with the so2 unplugged. On a flat road in 3rd gear at 3000 rpm keep the throttle very steady and very slowly reduce speed down to 850 rpm. Do this over 30 seconds or more - as slow as possible with the least amount of throttle angle change. You do not want the injectors to cut out, and want the MAP to be a flat line.
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s2000cr
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Re: Closed Loop Operation Calculation Issue with Fuel Trims - Continued

Post by s2000cr »

Please see attached datalog. Let me know the next steps.
Attachments
Secondary 02 sensor disabled and plugged out.fpdl
(10.78 KiB) Downloaded 13 times
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Re: Closed Loop Operation Calculation Issue with Fuel Trims - Continued

Post by Hondata »

Let's try another datalog. The goal here is to reduce the injector duration until the injectors shut down. So on a very slight down hill in 3rd gear and 2500 rpm reduce the throttle opening until the injectors shut off. What I would like to see is the lambda and fuel trims just before the injectors shut off.
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s2000cr
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Re: Closed Loop Operation Calculation Issue with Fuel Trims - Continued

Post by s2000cr »

Please see attached. Let me know next steps.
Attachments
Sec02 sensor disabled and plugged out 2500rpm V1.fpdl
(7.42 KiB) Downloaded 9 times
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Re: Closed Loop Operation Calculation Issue with Fuel Trims - Continued

Post by Hondata »

The datalog is inconclusive because the injector duration is not reduced gradually until the injector shut off. Also if disabling/unplugging the so2 is causing a problem, the doing that masking the underlying fuel trims.

Let's try another approach: how were the dead times tuned?
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