The below are snapshots of a failing MAP sensor and its impact on the motorcycle. The customer experienced an intermittent “wild bucking” while riding. Reproducing the issue on a dyno and recording the results showed a notable difference between normal function (green boxes) and when the sensor was failing (red boxes).
The TRo2 has red status LEDs for each channel. When powered, the LEDs blink at a slow rate until the corresponding sensor has reached normal operating temperature. After installation, the TRo2 requires free air calibration. This should be done with the sensors dangling in free air. The environment must be free of hydrocarbon vapors. It is suggested that the free air calibration be performed outdoors.
There are a few ways.
1. Using Direct Links recording features, watch for a high spike in AFR readings during acceleration. A sudden increase in air will increase the AFR dramatically and if this occurs in a normally rich condition, such as during acceleration, this is an indicator of a leak. Just be careful not to confuse the similar looking deceleration spikes with this issue.
2. Another method is to use carb cleaner or PJ1 spray. You have to be very careful not to let the spray curl into the air cleaner as it will give you a false indication. Perhaps make a card board cut away that slides between the air filter assembly and the gas tank. This serves to block the spray from curling into the air cleaner. It has to be tested with motor running. If you spray the manifold and the RPM drops and then returns, you have a leak. Spray from the horn side first very carefully and if no leak is found or the rpm does not change, then spray from the air cleaner side. The key is to make sure the spray does not get into the air cleaner as the rpm will drop giving a false read.
First, check for any intake leaks or possible faulty sensors. Tuning should ONLY be done on mechanically healthy motorcycles.
Sensor data is largely dependent on the sensor environment. For example, in some earlier model stock exhausts, the rear sensor is positioned poorly. This ends up causing the cylinder to be leaned out when “tuned”. The standard Harley motorcycle oxygen sensors are also limited by design. The sensor is designed to monitor AFR (lambda) to allow small real time adjustments in high MPG conditions, outside of those conditions, the sensor is unreliable and inaccurate. This is why Direct Links AFR mode using the motorcycles sensors creates a temporary lean condition and target while calibrating steps are taken.