Ph4tty

Well it finally happened- six months after replacing the lift pump with the vulcan lines/ fittings I finally managed to drag fp down to 12. It was kinda weird I was in no hurry to go to work so I'm just idling down the road in 4th and I look down and I'm sitting at 12 psi. I give it throttle, let off and its still sitting at 12. Then once I have the truck parked the fp never came back up. When I went to start the truck later it shot straight up to 15+ at idle and was 14 at cruise, but I am now able to pull fp down to 12 on a roll.

I assume I'm seeing the FF showing some miles. About 6k on it currently. When do you start thinking about changing the FF, when you can hit 10 or so? I thought FF's were supposed to be good for 15k?

Bart Timothy

Knowing what I know about the VP44 and fuel pressure problems, I never worry about fuel pressure until it drops to 3 or 4 lbs, but that's just me. Been that way for almost 6 years now.

DetroitDiesel71

Keep in mind that a F/O filter can plug with one bad load of fuel. But if you are monitoring the pressure regularly and against your mileage, you will know when its time. The truck will lose a bit of power when that filter gets pluuged.

Bart Timothy

Forgot to mention I change fuel filters every 30 to 35000 miles and have never had one plugged up yet, but always fuel up at the cheapest reputable stations avialable. Could have gone who knows how many miles more on the filters? Never experienced or noticed any lack of power as the fuel filters got more miles on them. Usually pull down to 5 to 6 lbs fuel pressure at WOT, but seldom need or use WOT (too much smoke, as one reason). Truck has over 140,000 on the odo and last dynoed 542 hp with a 1.05 correction factor.