You want to look at your Honda Del Sol's fuel feedback system. Your Honda Del Sol may very well be suffering from a lean fuel condition. Lean fuel conditions can cause high NOx smog check failures.
Your Honda does not have a mass air flow sensor, but it uses the map (Manifold Absolute Pressure) sensor along with the throttle position sensor and intake air temperature sensor to tell the ECU how much air is entering the intake manifold.
The oxygen sensor data is only one part of the air/fuel mixture calculation. The rest of the emission sensors should be inspected as well.
In this specific case since the NO increased after replacing the Oxygen Sensor we highly recommend ensuring the repair was done correctly, using the correct replacement parts.
posted by SmogTips Support
