Series 50G/60G Troubleshooting – Section 8.7 Fuel System Learn Procedure

Section 8.7
Fuel System Learn Procedure

Fill in the Air Fuel Ratio (AFR) table for the Fuel System follows:‪

Note: Use a chassis dynamometer to apply loads to the engine whenever appropriate as an alternative to on-highway vehicle operation.

1. Fill in the AFR table values from idle to No Load speed for the unloaded portion as follows:
   1. Reset the AFR table with the DDR or DDDL.
   2. Slowly increase the engine speed from idle to No Load (0–100 % throttle) and then slowly decrease the speed back to idle (100–0 % throttle) over one minute.
   3. Repeat step two times.
2. Fill in the AFR table values from idle to stall speed for the loaded portion as follows:
   1. With an applied load, slowly increase the engine speed from idle to stall speed (0–100 % throttle) and then slowly decrease the speed back to idle (100–0 % throttle) over one minute.
   2. Repeat step two times.
3. Fill in the AFR table above the stall speed for the unloaded portion as follows:

   Note: The engine must operate in this speed/boost range for a moderate length of time. The AFR table will not completely fill in just passing through this range.

   Note: The best method to apply a load through stall speed to 2100 rpm is to drive the vehicle up a hill, locked into a lower gear to prevent transmission shifting. If a hill is not available, lock the vehicle in low gear and accelerate from a stop to 2100 rpm full load.

   1. Slowly operate the engine from stall speed to 2100 rpm with an applied load.
   2. Repeat step until the engine runs smooth through this speed range.
4. Road test the vehicle as follows:
   1. Operate the engine through a variety of speed and loads while looking for any misfires.
   2. If a particular rpm/manifold pressure range still experiences misfire, then operate the engine around that point by running through that range slowly.
   3. Repeat step and step until the engine runs smooth without any lean misfires. A smooth-running engine means the Fuel System Learn Procedure is complete.