This vehicle does not use a Manifold Absolute Pressure Sensor. The 1972 225 slant-six has no electronic engine management system. Manifold vacuum diagnostics should be performed using a mechanical vacuum gauge connected to manifold vacuum port.

This vehicle does not use a Mass Airflow Sensor. The 1972 225ci slant-six engine uses a carburetor-based fuel system with no electronic engine management. Air/fuel metering is accomplished mechanically through carburetor jets, venturi, and metering rods.

This vehicle is equipped with a mechanical carburetor fuel delivery system and does not have electronic fuel injection. The 225 slant-six in 1972 used either a Carter BBD 2-barrel or Holley 1920 1-barrel carburetor with mechanical fuel pump.

At idle (750 RPM), expect clean transitions from 12-14V down to near 0V as points open. The primary should show 2-4 oscillations (ringing) after the initial voltage drop, dampening within 1-2ms. Dwell angle should be approximately 30-34 degrees on this 6-cylinder distributor system.

Secondary pattern should show sharp firing lines between 8-12kV with relatively consistent height across all six cylinders. Burn time should be 1.2-1.8ms with burn voltage around 2-3kV. Spark lines should be evenly spaced at 60-degree intervals in parade pattern, with slight increase in firing voltage on compression stroke.

The 1972 Dodge Challenger 225ci operates with no emission control computer, no catalytic converter, and no oxygen sensors. Emission controls limited to PCV valve, evaporative canister, and possibly air injection pump depending on California specifications.

The 1972 model year predates federal oxygen sensor requirements by approximately 5-8 years. This vehicle has no catalytic converter and no closed-loop fuel control, relying entirely on carburetor calibration for air/fuel mixture.

The 1972 225ci Slant-6 utilizes a gear-driven distributor for camshaft position reference. The distributor shaft is driven at half crankshaft speed via helical gear on the camshaft, providing mechanical timing reference only.

The 1972 225ci Slant-6 engine uses a conventional distributor with breaker points or optional electronic ignition conversion. No crankshaft position sensor exists on this engine as it predates OBD systems by over 20 years.

The 1972 225ci engine uses a single-barrel Carter BBD or Holley 1920 carburetor with fully mechanical throttle linkage. Throttle position feedback to any electronic system does not exist as fuel metering is entirely mechanical and vacuum-operated.

The 1972 Dodge Challenger uses a conventional hydraulic brake system with no electronic wheel speed monitoring. ABS technology was not available on production passenger vehicles until Chrysler introduced it in the late 1980s.

The 1972 Dodge Challenger utilizes a mechanical speedometer system with a flexible cable driven by a gear on the transmission tailshaft housing. No electronic vehicle speed sensor exists on this vehicle.

Cold engine shows 3.5-4.2V at ambient temperature (70°F), dropping smoothly and linearly to 1.8-2.5V at full operating temperature. Signal should be steady with no erratic fluctuations or dropouts during warm-up cycle.

The 1972 Dodge Challenger 225ci I6 uses a single-barrel carburetor with no electronic engine management system. Intake air temperature sensing was not implemented until later fuel injection systems in the 1980s.

1972 Dodge Challenger Waveform References

Airflow Sensors

Fuel System

Ignition System

Oxygen Sensors

Position Sensors

Speed Sensors

Temperature Sensors