VCM Scanner Wideband Readings Fluctuate Very Rapidly

[aka.LocK]

Hello,

Recently installed a 30-0300..

AEM Red extended to fuse 22 with 5amp fuse for switched
AEM Black was to chassis on driver sides at ground (G201), but went right to battery to test
AEM white to Prolink Red twisted together
AEM Brown to Prolink Black twisted together

Added to scanner under mpvi3 > prolink > input 1 Red
Transformed to o2 > air fuel > AEM 30 (03x0, 2340, 5130)

My gauge seems to read ok, but when i record in the scanner the voltage and the AFR readings vary wildly and very fast between 13-17 cant even tell what its at in real time trying to compare to gauge, noticing others recordings of scanners in videos it seems not normal. When recording voltage follows a similar pattern for input 1.

Attached is a short log file and a cell phone video recording in real time just idling (not the same as the attached log, but visually the same).

Any ideas? Is that normal? Exhaust leak?

2004 vette - t56 - intake, long tube kooks and exhaust only mods - no cats.

OEMBaseMod.hpt
7625.hpl


link to video if you want to full screen
https://vimeo.com/1099809350?share=copy

[danieltexpd]

Hello,

Recently installed a 30-0300..

AEM Red extended to fuse 22 with 5amp fuse for switched
AEM Black was to chassis on driver sides at ground (G201), but went right to battery to test
AEM white to Prolink Red twisted together
AEM Brown to Prolink Black twisted together

Added to scanner under mpvi3 > prolink > input 1 Red
Transformed to o2 > air fuel > AEM 30 (03x0, 2340, 5130)

My gauge seems to read ok, but when i record in the scanner the voltage and the AFR readings vary wildly and very fast between 13-17 cant even tell what its at in real time trying to compare to gauge, noticing others recordings of scanners in videos it seems not normal. When recording voltage follows a similar pattern for input 1.

Attached is a short log file just idling. Any ideas?

2004 vette - t56 - intake, headers and exhaust only mods - no cats.

OEMBaseMod.hpt
7625.hpl

I'm having the same issue... Wired correctly...Gauge reads great, but I can't make heads or tails of the scanner reading either.... I have an AEM 30-0400.


Hope someone chimes in with some input.

[bk2life]

when i record in the scanner the voltage and the AFR readings vary wildly and very fast between 13-17

Turn your O2s back on.
Use them for everything under 4,000 rpms.
use wide band for WOT runs.

Nothing really works well at idle. Your idle, for a stock vehicle is all over the place, you sure you dont have a cam in it?

[Lshungy]

In your scanner under the gauges layout there is a filter you can use to smoothen the gauge needle . This will only work for the scanner gauge and the channels reading may still fluctuate rapidly .

[Alvin]

Looks normal to me. The 02's are switching lean to stoich. The wideband will then have the same pattern.

[aka.LocK]

Turn your O2s back on.
Use them for everything under 4,000 rpms.
use wide band for WOT runs.

Nothing really works well at idle. Your idle, for a stock vehicle is all over the place, you sure you dont have a cam in it?

No cam yet, i actually have one and heads waiting to go in, but i wanted to dial it in before for dyno numbers to get a before and after.

My o2's are on.

I thought my idle was fine it varies within 20 rpm.

uploaded a new video of the scanner in real time old one expired.

Looks normal to me. The 02's are switching lean to stoich. The wideband will then have the same pattern.

The wideband doesnt follow same pattern it only varies like .5 afr normally sitting around 14.5-15.1 nothing like what the scanner shows getting into the 17's.

uploaded a new video b/c the old one expired, check that video out it looks nothing like other videos of scanners ive seen, mine is changing so fast you cant even read it.

[twenglish1]

Check wiring, solid tight connections, no twisted wires that you hope will stay touching, oscilloscope output of the wideband controller to make sure its not doing the same thing the scanner shows, compare it to your log, if output shows the same erratic fluctuation then something is likely wrong with the wideband controller assuming it has clean voltage input and all connections check out, seems likely since you said the display stays relatively steady.