DS4 Injection Pump General

Get the timing set and give us some data from your scan tool. We don't like to guess without data so you'll be scratching your head without doing this properly.

We want to see something like this for a properly installed pump:

• PMD resistor that matches the pump should have been indicated by the rebuilder and should be installed to match the pump so the fueling at idle is correct

• Base timing 3.5* per factory "TIME SET" procedure

• TDCO -0.50* per factory "TDCO LEARN" operation

• Lift pump pressure >5 PSI and <15 psi. No air in fuel system.

• Warmed up 170* Coolant temp readings:

  • 9-10mm^3 fuel rate in park at idle

    • If these are way off then you might have a pump to tune mismatch situation due to difference between 5521 and 5068 pumps

    • Having the wrong PMD resistor for the pump also throws this off

  • Desired timing 8-10*

  • Actual timing 8-10*

  • Closure Time/Pulse Width 1.6-1.8ms