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

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CBDZ-CBDZ
MS/Extra Newbie
Posts: 5
Joined: Sat Nov 05, 2016 3:20 pm

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

Post by CBDZ-CBDZ »

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?

MSQ and data-log are attached.
My Configuration:
1904cc Type 1 VW Engine (Air Cooled Classic Beetle)
MS1/Extra rev 029y4***********
Wasted Spark controlled via MS (no EDIS module)
Ford Escort Throttle Body w/ PMW Idle Valve
Matt Cramer
Super MS/Extra'er
Posts: 17499
Joined: Thu Apr 16, 2009 8:08 pm

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

Post by Matt Cramer »

A spark cut will give a false lean reading, not a false rich reading.
Matt Cramer -1966 Dodge Dart slant six running on MS3X
2swe
Experienced MS/Extra'er
Posts: 330
Joined: Sun Dec 25, 2011 12:41 pm

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

Post by 2swe »

you should do something to smooth your MAP, it's jumping up and down 8kPa with steady throttle and RPM.
there is a lot of false Accel Enrichments triggered by noisy MAP.
1978 vw golf gti 16v itb cop full sequential MS2
1992 vw corrado 16v moonlight blue MS2
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