Amp Draw – Fuel Pump Values

The following test should be done at home if you are experiencing difficulties with drivability. This will determine if your fuel pump is drawing more or less amps than is “normal” and give you a possible cause.

The test is an easy 3 step process using a digital multi-meter.

1. Set the meter to the 10A setting.
2. Connect one lead to the positive terminal on the battery.
3. Connect the other lead to the vehicle’s fuel pump prime connector. (If you do not know where this is, please check your vehicle’s service manual)

Typical values you will see are:

 

  • CPI = 8 to 10 amps
  • PFI = 4 to 6 amps
  • TBI = 2 to 4 amps

If the values you are getting are TO LOW, one of the causes could be:

 

  • Bad Ground
  • High Resistance Connection
  • Defective Fuel Pressure Regulator (FPR) with low calibration
  • Defective Fuel Pump (or connection)

If the value is TO HIGH, one of the causes could be:

 

  • Dirty / Restricted Fuel Filter
  • Restricted Fuel Lines
  • Defective Fuel Pressure Regulator (FPR) with to high of a calibration
  • Defective Fuel Pump