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Quick Specs

  • Size:2-1/16" (52.4mm)
  • Type:Digital
  • Range:6:1-20:1 AFR
  • Lighting:Digital LED
  • Instructions: Download PDF


Knowing the exact air/fuel mixture running through your engine is the most important factor to extracting the highest levels of performance and durability. Not all wideband gauges are created equal. AutoMeter utilizes an advanced calibration method that automatically calibrates your gauge on every startup to assure you of the highest degree of accuracy over the entire lifespan of your sensor (no free air calibration is ever necessary). Compatible with nearly all fuel types, the AutoMeter Pro Wideband has a configurable display to pinpoint the exact range you want to keep an eye on. An advanced peak recall function and lean warning system make sure you’re safely making power, whether on the track or on the street. An automatically dimming display tailors light output for any condition. Data logging output is included for one wire or two wire systems in both lambda or AFR. Our specially designed O2 sensor and wiring harness are included for ease of installation. Quite simply, there isn’t a more accurate or easy to live with wideband gauge available on the market.
Feature Points
  • Gauge kit includes custom tuned .1 AFR Resolution Bosch LSU4.2 Sensor, 8ft. wiring harness, 304 stainless steel weld-in bung, mounting hardware, and detailed instructions for installation
  • 0-4v data output feed for ECU, data acquisition unit, or Laptop tuning
  • User programmable range for Rich/Stoic/Lean conditions
  • Peak recall/memory
  • 10:1 to 20:1 AFR range for gasoline applications
  • 12 and 16 volt compatible, compatible with nearly every street car or race car electrical system
  • User Programmable Warning Function
  • Display data in Lambda or numerical A/F ratio
Ships With
  • Includes Sending Unit: 2243
  • M18X1.5 Fitting and Plug
  • Wire Harness: 5232
  • 2230
California Residents: Prop 65 WARNING prop65 Cancer, Birth Defects and Reproductive Harm


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Can gauge 3878 be had with a red LED in place of the green?

Asked by: Anonymous
This product is available only as shown. LED colors cannot be changed.
Answered by: Jim from AutoMeter
Date published: 2024-01-03

can it be uses with 110 racing fuel? About how long will sensor last?

Asked by: Bob3
This can be used with the following: Unleaded Gasoline Methanol Ethanol LPG (Propane) CNG For the life of the sensor however there is no way to determine the life of the sensor for the fuel type you are using.
Answered by: Steve from AutoMeter
Date published: 2022-12-19

What is required to use this gauge on my 1967 Firebird 400 V8 with a Rochester Quadrajet and long tube headers?

Asked by: Renato
Renato, The bung will need to be installed 8-10" away from the collector on the header. The O2 sensor installed in said bung, along with the gauge having +12.5v and ground.
Answered by: Steve from AutoMeter
Date published: 2022-04-29

Hello, just curious is the outer ring on this series of gauge is chrome? Im trying to match it to my cadillac cluster, thanks

Asked by: Austin12345
Hi Austin, thank you so much for contacting us. The bezel on this gauge is what we refer to as a "bright anodized" finish. While it is more shiny than a brushed or stainless finish, it's not a full chrome. We could certainly do a special order for you it you'd like to have one built with a chrome bezel though. If you're interested, give us a ring at 866.248.6356 and we'll be happy to help.
Answered by: Joseph At AutoMeter
Date published: 2020-04-07

Hi, I own this gauge and a couple of the “lights” burned out on the digital readout. I was wondering if I was able to get it sent out for repair or if I was able to purchase the gauge all by itself without any wiring or sensor. Thank you

Asked by: Duatin
Hi Dustin, thank you for contacting us. We're sorry for the lights that are not functioning properly. We do not sell just the gauge head, but we can absolutely service your gauge if you'd like to send it in. While this form is not required, it will give you some direction and the information we'll need if you send it in:
Answered by: Matt from AutoMeter
Date published: 2018-04-06
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