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Last night when i left work I noticed my fuel pressure was running about 77 psi, it normally runs about 68psi. today I took my daughter to practice and it was around 83psi, on the way home it was up to 95psi, so I parked it and took another truck to work.
About a week and a half ago I lost fuel pressure going down the highway and the truck died, finally decided my pick-up foot must have come off and had my sister in law bring me some diesel and it has drove fine ever since. (it was right at a quarter tank).
I have the FRX from riffraff and am thinking some pieces of that foot have got into the fuel bowl and plugging up the return. Any other ideas? things to check? Could it be a problem with the fuel gauge or wiring, and how to test them. It is an autometer gauge from riffraff.
It will probably be a few weeks before I can do much more than clean out the fuel bowl. I don't have anywhere inside to work on it and it's been rain/sleet/freezing rain/snow for the last 10 days. I have most of the stuff to do the hutch mod and its next on the list but was hoping to put it off till spring.
Also when I was on the side of the road I pulled the filter to see if I had fuel and some how tore the seal when I re-installed it so it was leaking, so i put new filter in the next day.
The fuel pump regulator may be collapsing, letting the spring move and causing pressure changes (usually goes down rather than up, though).
46 psi and above should keep the truck running.
2. Gauges do go bad. A manual gauge on the test port on the back side of the fuel bowl is one way to double-check your gauge.
3. There is no way that pieces from your pickup foot in the tank can get into your FPR or fuel bowl. The fuel pump under the driver's seat has a built-in 64 mesh screen in the bottom of it which is even before the internal pump components. Here is a link to where I tore down a fuel pump almost two years ago (the pictures show the screen I'm referring to). https://www.ford-trucks.com/forums/1...-and-pics.html
Once I used an integrated fuel filter/cap. It was slightly tight getting it to thread into the bowl, but I thought nothing of it. A while later I had fuel pressure problems, and found a pointy sliver of the cap material had evidently sliced off during installation of the filter. One end was poked into the hole on the brass plunger in the FPR, and the other end was interfering with the body of the plunger.
Only Ford or Racor filters with a Ford cap from then on.
When my fuel pressure went up to 75-80 psi it was due to a clogged fuel filter. I've also had thefuel pressure sending unit go out on the gauge numerous times. I hadn't had any luck getting them to last more than a couple of years.
When my fuel pressure went up to 75-80 psi it was due to a clogged fuel filter. I've also had thefuel pressure sending unit go out on the gauge numerous times. I hadn't had any luck getting them to last more than a couple of years.
I'm beginning to suspect the sending unit, is there any way to test them? ohm them out or something? It has been on there about 2 years.
I pulled the fpr tonight and didnt find anything, even put one of the other springs that came with the FRX. Still about 100 psi. I also pulled the gauge and reprogrammed it with the attribute program from isspro.
Next step is to install a schrader valve so I can put a mechanical gauge on to see where The pressure actually is. Anybody have a parts list, or know what size fitting I need for that?
One thing to do is call ISSPRO. They will ask you for the serial # off of you sending unit to see if it is one of the new models. The new models have a much lower failure rate than the previous units. Clay (RiffRaff) also sells them on his site.
I don't know of a way to test them myself. I haven't had a problem with the new units.
Also check the Fuel Filter Check Valve Assembly. If the fuel filter is an aftermarket one it can sometimes not seat correctly and cause the check valve not to open and result in a restriction & higher pressure, but not normally at idle.
Thanks, I ordered a schrader valve and a new filter form bob, the one in it is a napa filter, then I can see what the pressure actually is to see if the sending unit is bad. Hopefully I can get that done next week.
Got the schrader valve on and a rancor filter from Bob. still at 100 psi on the gauge, but 65 under the hood. Called Isspro and they had me check voltages on the back of the gauge and decided the sending unit was bad. It is the old style. So they are sending me one, hopefully it will be here this week.
At least now i'm not scared to drive it.
Got the schrader valve on and a rancor filter from Bob. still at 100 psi on the gauge, but 65 under the hood. Called Isspro and they had me check voltages on the back of the gauge and decided the sending unit was bad. It is the old style. So they are sending me one, hopefully it will be here this week.
At least now i'm not scared to drive it.
FOUND THE PROBLEM Glad you got it resolved. I have found the Holley sending units to be pretty darn reliable, and I hate to say it but the autometers I have never had a problem with.
12-01-2015, 01:35 AM
Glad you got it resolved. I have found the Holley sending units to be pretty darn reliable, and I hate to say it but the autometers I have never had a problem with.
