Strange "Rich" reading at 5000-5500 RPM, 95 KPA

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CBDZ
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Strange "Rich" reading at 5000-5500 RPM, 95 KPA

Post by CBDZ » Mon Nov 07, 2016 12:04 am

I have been creating high RPM, full throttle data-logs.

I keep getting a consistent rich reading right about 5000-5500 RPM / 95KPA. The data log shows that the AFR drops to 9.0:1 (about), which in turn makes the
'VE Analyze" pull out fuel in just those few cells. All the surrounding cells stay the same, which then creates a crater in my VE table.

Could this be caused by the Rev. limiter, which cuts spark, therefore confusing the system to think there is un-burned fuel, causing a rich reading? If this is the case, should I simply turn off rev. limiter, and tune this area, being very careful to not redline?

Is there something else that I need to adjust to correct my data collection?
My Car Details:
Fiberglass Buggy on 1973 Chassis.
1904 cc
Megasquirt (MS1 with 3.57 board) Fuel Injection: German Intake Plenum, CB Performance End-Castings, Ford Escort Throttle Body with custom Adapter, MS controls Wasted Spark Coil Pack

66brm
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Location: Perth, Western Australia, The Southern Hemisphere

Re: Strange "Rich" reading at 5000-5500 RPM, 95 KPA

Post by 66brm » Mon Nov 07, 2016 1:51 am

Electrical misfire?

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ps2375
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Re: Strange "Rich" reading at 5000-5500 RPM, 95 KPA

Post by ps2375 » Mon Nov 07, 2016 10:30 am

Unburnt fuel does not cause a rich reading, as the O2 sensor measures oxygen, meaning if you have a lack of combustion, you will have a lean reading due to the abundance of oxygen. And a "crater" in your table means nothing, it won't be smooth and pretty like some people think it "should" look. Let the TS do it's job and see how it drives.

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CBDZ
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Re: Strange "Rich" reading at 5000-5500 RPM, 95 KPA

Post by CBDZ » Mon Nov 07, 2016 12:29 pm

I've added another value to the log, and have realized that the injector duty-cycle is peaking at above 100. How could this be affecting my recorded data?
My Car Details:
Fiberglass Buggy on 1973 Chassis.
1904 cc
Megasquirt (MS1 with 3.57 board) Fuel Injection: German Intake Plenum, CB Performance End-Castings, Ford Escort Throttle Body with custom Adapter, MS controls Wasted Spark Coil Pack

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ps2375
Posts: 302
Joined: Mon Aug 18, 2014 10:04 am
Location: Meridian,ID

Re: Strange "Rich" reading at 5000-5500 RPM, 95 KPA

Post by ps2375 » Mon Nov 07, 2016 12:37 pm

If your duty cycle is above 100, you need bigger injectors or more fuel pressure.

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