Wideband AFR Gauge with the Haltech WB1 or WB2

A wideband O2 sensor is the most important sensor on a tuned engine: it tells you whether the engine is running rich, lean or right on target, in real time. The Haltech WB1 (single channel) and WB2 (dual channel) are compact CAN wideband controllers built around the Bosch LSU 4.9 sensor — and a KrispyGauge turns them into a bright, easy-to-read AFR gauge in a standard gauge pod.

Why a wideband gauge matters

• Catch a lean condition early. Running lean under boost is one of the fastest ways to damage an engine. A live AFR readout, with a warning you can't miss, gives you the chance to back off.
• Tune with confidence. See exactly what the engine is doing on the road, not just on the dyno.
• Diagnose problems. Fuel pressure, injector or sensor issues usually show up in the air-fuel ratio first.

What you need

• A Haltech WB1 or WB2 kit — the controller, Bosch sensor and harness.
• A KrispyGauge on the same CAN bus.
• Power and CAN wiring — on a Haltech-style CAN bus, DTM-4 CAN cables and a CAN hub make the connections plug-and-play.

With or without a Haltech ECU

KrispyGauge reads the WB1 and WB2 directly over CAN, so the controller doesn't have to report through an ECU first. That means it works:

• Alongside your ECU — the wideband shares the CAN bus with your Haltech or other supported ECU and adds AFR channels to the gauge.
• On its own — a WB1 or WB2 and a KrispyGauge make a complete wideband gauge for a car with a factory ECU or no CAN-capable ECU at all.

Wideband controller support is currently in beta. If anything doesn't look right, let us know and we'll sort it.

WB1 or WB2?

• WB1 — one sensor. Right for most four- and six-cylinder engines with a single exhaust.
• WB2 — two sensors. For V6 and V8 engines, twin-turbo setups, or anywhere you want to see each bank separately.

KrispyGauge shows lambda and AFR for each channel, updating 20 times a second. Channel 1 also feeds the gauge's main AFR reading, so it works on any page laid out for AFR.

Setting it up

1. Wire the WB1 or WB2 to power and to the same CAN bus as the KrispyGauge.
2. Join the gauge's WiFi network (Krispy_XXXX, password GetKrispy) and open http://4.3.2.1.
3. Under Settings, choose the wideband device — WB1, or WB2 device A, B, C or D to match how your WB2 is set up — and set the CAN bus speed to 1 Mbit/s.
4. Under Page Config, set a page to AFR or lambda for each channel you want to see.

Every signal is listed on the Haltech WB1 / WB2 supported signals page, and connection details are in the Web UI guide.

Set a lean warning

Give the AFR page a warning threshold on the lean side of your target. If the mixture goes lean, the gauge flashes a full-screen alert. If a sensor reports a fault, its reading blanks rather than freezing on an old value — so a number on screen is always a live one.

Common questions

Do I need a Haltech ECU?

No. The WB1 and WB2 work with KrispyGauge on their own, or alongside any supported ECU on the same CAN bus.

Can I show two widebands at once?

Yes — a WB2 gives you two channels, and each one can go on its own gauge page.

Does it need a terminating resistor?

A CAN bus needs termination at each end. KrispyGauge has a 120Ω resistor built in that you can switch on in the Web UI — see Should I use the 120Ω termination resistor.