Heading home from work today and I noticed that my fuel pressure was low.. very low... around 9-10 psi I shut it off and restarted and it didn't change. It continued to get lower, by the time I limped it home I was seeing 4-5 psi and under slight load I saw 0-1 psi!!. I usually see around 18-21 psi and around 15 psi when I have my foot in it. I did my fuel filter last weekend (2/1/14), I run power service arctic formula, I don't run it below 1/8 tank, I have a raptor 150 LP. I was thinking there was a filter in the raptor unit so I took off the 4 allen heads on the bottom and there is no filter there just lots of frigid diesel (10* here). When I turn the key to run I can hear the LP make a loud hum for 1-2 seconds, like a labored electrical motor, this is new because I don't remember hearing that before. Has my LP crapped out? Is there something simple/stupid I'm missing? I did fill up at fast trac yesterday and it was an extremely slow pump, 20 for $100 worth.

 

I always thought the lift pump was suppose to run for 20 seconds so if it's only running for a few seconds I'd replace it

 

Well the air dog is known for its problems. Frequent failures that pop up randomly. Do a bucket test or use a vacuum extractor to verify your getting fuel from the tank. Typically without fuel the pump sounds faster maybe I higher pitch tone. I have no clue if that's how it should be described . If it's motor issue you'll typically hear a deeper sound or a rough possibly grinding sound. Maybe you could get a video of what it sounds like. An amp clamp and oscilloscope are the fastest way to diagnose an electric motor...and most expensive

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