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LambdaKing Mk II - Air Fuel Ratio Tuning Meter
LambdaKing Mk II - Air Fuel Ratio Tuning Meter
LambdaKing Mk II - Air Fuel Ratio Tuning Meter
LambdaKing Mk II - Air Fuel Ratio Tuning Meter
LambdaKing Mk II - Air Fuel Ratio Tuning Meter
LambdaKing Mk II - Air Fuel Ratio Tuning Meter
LambdaKing Mk II - Air Fuel Ratio Tuning Meter

LambdaKing Mk II - Air Fuel Ratio Tuning Meter

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The LambdaKing from RaytechAutomotive is a workshop tool for measuring the oxygen content of exhaust gasses, to enable fine-tuning of the air to fuel ratio (AFR). Featuring the latest LSU 4.9 technology wideband sensor, the LambdaKing is accurate, easy to use and an incredibly economical option for both the professional tuning workshop and the enthusiast.


The LambdaKing MkII will work with any piston engine running on gasoline, diesel, LPG, Methanol and E85. Whether you’re tuning a single, twin or quad cylinder motorcycle, a petrol V8, turbo diesel 4x4 or track car running on dedicated E85 the LambdaKing will deliver the same ease of use and accurate readings it's renowned for.


Included with the LambdaKing is a premium LSU 4.9 wideband sensor, that can be inserted into an existing socket in the vehicle's exhaust system, or via the included weld-on bung. Alternatively, our Sniff Stick tailpipe adapter to place the sensor into the exhaust stream.


Use the LamdaKing to fine tune the air-fuel mixture in your vehicle, one of the most critical parts of any engine tuning exercise. Optimal air-fuel ratios are the key to good engine performance, throttle response and economy. Running too rich will cost you power, response and economy, while running too lean can endanger your motor with critically high temperatures.

Run your engine smoother, more economically and with higher power output with smart, data driven tuning.


The LambdaKing measures oxygen content in the exhaust system in real-time, and so displays current oxygen content in the system - enabling reliable and accurate tuning.

The main numerical display shows the Lambda number within a 0.67 to 6.50 range. The main display can be switched between Lambda and AFR display as preferred with the press of a button. 

The sliding bar-graph offer a supplementary at-a-glace display of Lambda within a 0.75  to 3.75 range.

Select the fuel-type from the provided options to allow the LambdaKing to calculate the AFR from the Lambda wideband measurement.


The LambdaKing MkII runs from the vehicle's electrical power but will accept any 12-14.2V DC supply, and doesn’t require batteries. The LambdaKing MkII comes with a built-in power lead and clamps for connection to the vehicle battery poles. Cable length options are:

  • Standard - 1900mm
  • Extended 3m - 3000mm
  • Extended 5m - 5000mm
Sensor cable lengths include approximately 900mm sensor loom, see the diagram.

Key Features:

  1. 100% Australian designed and manufactured.
  2. The most cost effective device in its class.
  3. Quality and robust housing.
  4. 100% function test of each unit before dispatch. 
  5. Storage pouch included.
  6. No battery required.
  7. Air Fuel Ratio Tuning made easy.
  8. 1-year limited warranty for the original Purchaser.

Included in the kit:

  • 1 x LambdaKing MkII device, c/w integrated power lead
  • 1 x LSU 4.9 Wide Band Oxygen Sensor
  • 1 x M18 x 1.5 socket
  • 1 x M18 x 1.5 plug
  • Storage Pouch


See the Manual for full specifications and warranty Terms (Sensor warranty limited to DOA cases only):

Free Manual Download

Customer Reviews

Based on 46 reviews
Peter Ready
Buyer Beware!

On arrival I thought the product was well packaged and looked like a quality product. After welding the supplied plug into the exhaust system, as recommended in the instructions, I warmed up my vehicle then installed the O2 sensor. Then connected the LambdaKing Mk II and restarted the engine to take some readings. The LambdaKing Mk II did not respond as I expected, and it quickly locked in the centre of the dial. The only way to get it to respond was to power it down and then power it up again. It did the same thing again. After much trial and error and re-reading the instructions, I called the manufactures for help. Beware! There is no help given. They would not enter any conversation to help me decide if I had made an error in installation or if I was using the LambdaKing Mk II incorrectly/correctly. They just kept on saying, “If you think it is faulty, return it. We will check it on our test bench. If faulty, we will honour the warranty. If it is the 02 sensor that is on you. No warranty.”

Hello Peter,

Thank you for your feedback.

We are somewhat surprised by your assertion that no help was given, because we spent quite some time on technical support on the phone, during which various fault finding options were discussed. We also discussed a possible warranty repair of your device which was declined.

As we tried to explain, we are not able to remotely determine why your vehicle produced unexpected readings without knowing all the local variables. What we can do is make sure that our products work reliably by 100% function testing each device, and offering a 1 year return to base warranty, which on this occasion was declined. That leaves us without any real options to assist you.

As stated on our website and in your manual, the sensor is warranted is limited to dead-on-arrival cases because it is a wear part that is sensitive to contamination. In this case it did appear that exposure to high levels of unburnt fuel may have been a factor.

Excellent piece of kit

I'm only a hobbist getting and old '70's 911 going again - the LamdaKing MkII is fantastic, easy to use and understand -- great piece of kit !!!

Gerrard Neep
Lambda king

Great product and easy to use, makes tuning carbs so much easier

Errol Strasburg
Completely happy

This is a very useful tool for setting up a carburettor or a fuel map. I am pleased with my purchase Very simple to use

Ryan Wendel
Awesome tool

What a great tool for tuning. We use it for the first time today on a carburetor tune and holy cow what a difference it was to have live readings. The price was even better. Super happy with this tool!!!! Excited to use it more


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