One new #5 and #9 calibration resistor for PMDs on 1994-2002 6.5l diesel applications.
Calibration resistors were used by GM to adjust the maximum fuel rate on the electronic DB4 pumps found on 94-02 6.5l engines.
The resistors are installed in the female plug on the PMD. They slide down on the terminals and can be removed with a paper clip or snap ring pliers.
Most pumps came with a #4 or #5 resistor, however a common upgrade is to replace a lower value resistor with a #9 resistor for maximum fuel delivery at wide open throttle. The #9 resistor will add about 6% to the maximum fuel delivery.
Remember the PCM will only find a new resistor after about 50 drive cycles, overnight battery disconnect, or a scan tool learn procedure.
