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VP44 Troubleshooting

VP44 Troubleshooting Quick Reference


Miss or buck

Often felt while driving or in the throttle pedal at different throttle applications. Sometimes a crackling sound is heard.

Intermittent Miss

Intermittent miss above idle, at higher RPM at light to moderate load and throttle positions.

Idle Skip

Rough or erratic idle or skip at idle only.


Doggy on take-off or low power, usually cold but sometimes hot, or can't make the boost you are used to seeing.

RPM Takes Off Without Throttle Application

  • RPM goes up on its own or

  • Wait to start light is dumb or 

  • Supply voltage to the APPS and MAP sensors is erratic or out of range or

  • Delayed 12V power to the lift pump and injection pump or

  • See a 606 code

Dead Pedal

Dead pedal or intermittent loss of power. You are driving down the road and you lose all response to your throttle pedal, typically while this is happening you are losing road speed. When the engine slows down enough, it senses where it is again and throttle action comes back. Or you have to restart the truck to gain back throttle function. 

Truck Dies Going Down The Road

Low Power, Cold

Truck is gutless when driving at first after a start up cold, and then all of a sudden takes off and runs fine.

Hard Start, Hot

Long crank times after truck is warmed up. Typically running errands or stopping at a drive-thru. Hot truck won't restart.

Hard Start, Cold

Long crank times during cold morning start. 

Long Crank Times

Hard start, long crank times, usually when cold but sometimes hot, runs for a few seconds after start and then clears up and runs smoothly, or engine sounds different or louder under load, or makes crackling sort of sound.

No Fuel At Injectors

Long cranking, no start, opening injectors to bleed air, no fuel. 

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