Digital Wideband UEGO AFR gauge reads 14.7 continuously | AEM
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mbriggs01
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Last seen: 5 years 5 months ago
Joined: 01/16/2015 - 10:57
Digital Wideband UEGO AFR gauge reads 14.7 continuously

I have a wideband digital AFR gauge and the gauge that has now settled on 14.7 all of the time.  The gauge looks like it is going through all of the powerup process corectly but once it gets fired up it reads 14.7 no matter what.  The gauge was initially working but I did some work on the exhaust and am concerned if I damages the sensor in the process.  Is there a way to test the sensor or do you just have to replace and hope for the best.  I had sent this in to tech support but never got a response.  Any help would be greatly appreciated.

AEM_NS
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Last seen: 14 hours 14 min ago
Joined: 06/06/2014 - 09:31
Did you email tech support

Did you email tech support about this?  What email address did you use?  When did you send it?

Re the sensor, the gauge showing 14.7 all the time usually means that the sensor is disconnected.  The sensor controller in the gauge pumps current in and out of the Nerst cell to maintain a steady stoich state.  When there's no current being pumped in or out it's because the O2 is at stoich which is ~14.7.  The other time there's no current being pumped in/out of the sensor is when the sensor is physically disconnected from the controller thus the gauge thinks the O2 is at stoich and shows 14.7.  Keep in mind that disconnected can mean physically unplugged from the back of the gauge or broken wires in the sensor harness.  You'd be surprised to know how many times people report this problem and then look under their car to find their sensor wires have been rubbed through by dragging on the ground.

Here's some links on testing the sensor:

Forum Post 1

Forum Post 2

YouTube Video