My pickup used to consistently get 17+ mpg on summer fuel and the 16 neighborhood on winter fuel. But for over a year my mileage has very slowly decreased. Seems like it started with a really bad tank of fuel about 14 months ago. The engine also seemed to be producing more injector noise. I suspected the fuel pump, even had the pump off and test ran it. It seemed to have good volume but I never actually checked the pressure. By this March my mileage was down to about 15 mpg even when I was running propane. I was beginning to think it was time for injectors at 140,000 miles.

Last December I got a screaming deal on a new Ford factory fuel pump on e-bay, but never got around to putting it on till last weekend. The first 2 tanks since the new pump have been 18+ mpg with propane. The injector noise is also noticeably less.

Looks like I got more time to save up for those injectors.

 

Hey, could you try that without the propane and give us some numbers? I wonder how long the stock pump is good for.

 

I will probably run out a tank without the C3H8 next week. I'll post back what I find.

 

I also would like to see the numbers with out propane, I'll be waiting to see your results.

 

I wouldn't be surprised if a whole lot of PSD's out there need pumps and the owners don't even realize it.

 

That's what I've been thinking for a long time.
Are the early '99's and later models inter change able ??

 

yes, all the superduty7.3's have the same pump.

 

hmm now your making me think maybe I need to go change mine since the first couple years I owned this truck I would consistantly get 17-18 (both lie-o-meter and actual checking it was always withing .5mpg) now the lie meter says 13-14 consistantly and actualy ends up bieng anywhere from 12-15 depending. but I did notice an increase when I did hte prepump mods although haven't checked since I did the prepump, pump yet.

 

There's no substitute for a good, constant, consistant fuel supply.
Monsterbaby I recommend that you hook up a fuel pressure guage on the end of a long hose and go out and WOT. See what happens above 2500 rpm.

 

i am thinking about doing this too, where would i hook up the pressure gauge and what kind of a pressure gauge should i get? also what are good numbers and what are bad numbers? thanks.

 

You should see a constant aprox 55 psi no matter what the throttle setting, engine load, vehicle speed, etc. Idle to Wide Open Throttle, it should remain the same.

 

i checked mine by making up a hose long enough that attached to the 1/8 inch npt port near the front of the head and attached a 0-100 psi gauge to the other and duck taped the gauge to my windshield ( in an area that i could see while i was driving and did not obstruct my view) then went out to the biggest hill i could find and put the petal to the floorboard. probally not the sefest way to check the pressure, but it worked for me. the hose that i used was small enough that the weather stripping flexed enough that i could close the hood.

 

How long is the stock fuel pump expected to last? How much do they run and is there a better one that will last longer or give better results or just stay with a stock one for most applications?

 

In ideal conditions a fuel pump should last at least 200,000 miles. Ford's pump is made by Bosch. Bosch also makes fuel pumps for the VW and Audi's that I work on every day.
What kills these pumps is air in the fuel.
Where the air comes from is the quick connects on the fuel line from the tank to the pump and, if one insists on running thier tank low all the time, from the mixing chamber in the fuel tank pickup.
If you want something better than stock like I did, there's a few options that work well.
Here's what I did.

https://www.ford-trucks.com/forums/s...d.php?t=440448

.

 

I think I am going to have to see what my pressure is after i get back from camping, I always have gotten around 14-15 on average. Now I wonder if a new pump would take it up to the 17 most with similar setups to mine get. that would make up for cost of pump in hurry with todays prices and tomorrows ever increasing.