fuel pressure

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03-22-2006, 07:17 AM

#16

trik396

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Taking a reading off the top of the filter housing is pre-filter pressure. That's going to drop a few psi once it passes thru the filter itself. I'd be worried at anything approaching 5psi...
My pressure would drop to zero at wot with my minor mods. This was at the cp3. I don't have that problem any more...

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03-22-2006, 07:19 AM

#17

MikeyB

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Quote:

Originally Posted by eb290

Ok, went back to the stock setting today, (disconnected the EZ) like yesterday, everything was fine for a while then the pressure started dropping. I left the house at 5:30 this morning, drove to the location to pick up the tools, I had to load them myself with my winch so I had a lot of idleing. By the time I got back to the yard at about 1:00 it was no different than it was running the EZ on level 2. The slightest hill or pull would peg the pressure below 0.
When everything is cold, the pressure is fine. The longer I run, and I will run the engine sometimes 10 - 12 hrs at a time, the lower the pressure gets. Is the fuel getting hot and causing this? Is the pump getting hot and loseing effiency? This is with a new filter put in yesterday. This is an in-tank pump, put in on Dec.22, last yr. Any ideas?

Is the truck running fine with zero pressure? If so I would look at your fuel pressure gauge/sending unit before doing anything else.

MikeyB

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03-22-2006, 08:09 AM

#18

trik396

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Mikeyb- I thought my truck was running good with the xzt but I always had this kinda flat spot around 2000rpms. Now that my pressure is higher, flat spot is gone and she pulls like a freight train all the way to redline...

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03-22-2006, 06:06 PM

#19

eb290

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Today all my pressures were normal, (10lbs at idle, 6-8 towing the trailer at 70 mph. Never varied all day, I could make it go to 0 psi if I went to WOT pulling the trailer, I don't normally drive like that though. The truck runs fine at O pressure so I also wonder about the pressure sending unit. Any way to ck them?
One other thing that might make a difference is that I have a 40 gal fuel tank on the bed tied to the main tank. Basically one 75 gal tank. Could the extra "head pressure" keep the pressures up when the tanks are full and when I'm just running on the main tank allow the pressure to drop if the pump isn't quite what it should be? Just thinking out loud.