Fuel pressure gage used to read, 75psi, now read less then 10, truck runs good

Howdy All,

I use my 2001 379, to tow my large RV trailer so it doesn't get used often but covers many miles in a short time when it is used. I start the truck and let it run for a half hour once a month, the last time I had it running the fuel pressure gage read as it has for the last 50,000 miles that I have owned the truck the needle twitched and held a steady 75 psi. Today when I started the truck the fuel pressure gage read less then 10 psi and moved a few psi when I reved the engine from idle ( 750 rpm ) to 1,500 rpm. The engine seems to be running just fine but it's NOT under a load. Where do you folks suggest that I start looking to see if I have a problem that needs to be corrected before I leave to go south for the winter. I don't want to be stranded on the road so any advice will be greatly appreciated. THANKS.

Dave

 

Howdy Lyle,

That was my first though but as I don't have a spare gage and don't want to spend 150 bucks an hour unless I have too I was hoping someone would have a different suggestion on what might cause this problem "IF" the gage is reading correctly. Thanks for your reply.

Dave

 

Howdy Lyle,

Just checked my records I am due for an oil and filter change so I will give that a try before I get all worked up. Because the truck sits for months at a time I am sure crud gets in the fuel tanks, the last time I changed fuel filters the first filter had a bunch of gray slime on the top of it when I took it off the frame mount, the fuel filter on the engine didn't have that gray crud.

Dave

 

Howdy 062,

I am not familiar with a "reed valve" in the fuel system. I built this truck going on 6 years ago, the fuel pressure gage has always fluttered/twitched a bit at 75 psi. Do you know if this is located someplace a person can get at it, take it out and clean it? Thanks for any other information you can share.

Dave

 

Howdy wore out,

I kinda figured it would need more pressure then 10 psi to run correctly, which leads me to suspect either the gage or as 062, suggested something in the fuel line that's causing a low reading. I will do some more research and see if I can just disconnect some lines and blow them out with air. When we go south we usually go down through Nevada on Hwy 93, many miles of high desolate country very bad place to have problems or break down, in the summer let alone the early part of December when we will be traveling.

Dave.