Hi all,

Ok, I need some advice and need to know if I am understanding my new truck correctly. Been doing a lot of reading on here but still am trying to comprehend it all.
1995 F150 4x4 SuperCab, 5.0, Auto, dual tanks, all stock except the automatic hubs have been replaced with manual hubs. So there's dual tanks, and each tank has a low pressure pump and sending unit to the guage in each tank, and then there's a high pressure fuel pump on the frame rail before the fuel filter. Is the jist of that correct?
Now when I turn the key to the on position before I crank the motor, the ecu tells the high pressure pump to run for a few seconds and then waits until the motor starts. I can hear the relays and I hear the pump run for a bit, then I crank the motor and she starts. Is that correct?
So my new issue today is I turned the key to the on position, I heard the relay but not the pump, I crank and she won't start. I turn key to off and try again, try again, try again, then when I hear the pump come on for a few seconds the motor starts. Runs fine, go to work etc all good. But two or three times, i turn the key and do not hear the pump and she won't start.
Do I just replace the high pressure pump? It's new to me and I have focused on changing all the fluids, tires, brakes and have not changed the fuel filter yet. Will a clogged fuel filter put too much pressure on the line and make the pump not operate? Could changing the filter fix the issue? I know I'll change it no matter what. I read about the Fuel Pressure Regulator but unsure what it looks like, I have general idea of where it is but still a bit fuzzy on it and whether it would be part of the issue I am having. Sorry for being so long a post but trying to give the right info and trying to figure it out my self to a point.
Thanks

 

There is NO high side pump on the frame of this year truck. The fuel pump is located in-tank. It's the whole unit.

Earlier years '86-90, and a few other oddball vehicles retained the high and low pumps until the '91.

You need to check the wiring leading to the pump, or pumps if you have dual tanks.
It sounds like the fuel pump relay isn't making contact well in the main fue block under the hood. Remove it and see if there is corrosion or swap relays around to see if its just a weak/ intermittent relay problem.

Others will chime in with a more detailed idea.

 

Have you switched tanks when your having the issue.

 

If the fuel tank switch came disconnected, the pumps will not run also.

 

Your truck has an FDM (Fuel Delivery Module) in each tank. Each FDM contains a high pressure electrically-driven pump, a mechanical (venturi-type) scavenge pump, and a couple of valves which are actuated by fuel pressure alone.

Next time you turn the key and don't hear the pump, leave the key on and smack the bottom of the offending fuel tank (whichever one you have selected that won't work) right under the fuel pump with a rubber mallet or a few good kicks from your work boots or whatever else you got, then turn the key straight to start (don't try to recycle the pump manually) and see if she starts. If so then your HP fuel pump, inside the FDM in that tank, is starting to sieze up and will need replaced. Easiest to replace the entire FDM if it's original because sooner or later the valves will start leaking and you'll have the fuel crossfeed problem.

 

Thanks for setting me straight on where and how on the pumps. I had already checked the seating of the fuse and relay so today I went ahead and replaced the relay thinking perhaps that will clear the issue. I purchased a new fuel filter and tool to replace it because I should no matter what. Like it would have killed Ford to place that filter five inches towards the front so we could have some room to remove and replace it, geez, that is going to be a pain in the ...

I've had it not start on both tanks, and start normally on both tanks so I did look at the wires going to each tank and snooped around as best I can...not a lot of room to see anything. My tank selector switch is loose on the dash but when I switch the tank levels adjust accordingly so I don't think that is the issue but since I need to get that secured anyway, I will.

Next time it doesn't start I'll bang on the tank and see if it makes it go. I recall I had an old Chevy Nova that I banged on the starter for two weeks until the next pay day. Thanks for the advice. I will report back on what happens next

 

Thanks for the reminder dixie460!! It's been some years now since I had to do that with my steel toe boots or the trusty wooden stick I kept in the bed!!

 

It's not very likely to have both FDMs going bad the same way at the same time.
It's much more likely it's an electrical issue in the switch, or upstream of the switch.

 

^^^ I vote for a bad PCM Computer as this what they do when the caps start to go.
The fuel pressure regulator would have nothing to do with this problem and neither would the fuel filter.
The fuel filter is for the fuel injectors and I am not sure why every one keeps changing them.
All of my fuel injected Fords as far as I know still have the filter they came with from the factory.
If your filter does need to be changed you would have bad tanks and you need to change the fuel tanks and the FDM in them along with the filter.

 

If there is a bad connection on this switch, it could cause intermittent die/no start. Its probably loose because the plastic that holds it to the panel is broke, but it might pay to check here.

 

So how do I remove that section of the dash to get at the tank selection switch?

 

I'm curious to know if your filter medias are still intact after this long?

 

I'm confused as to why you wouldn't replace your fuel filter. I have replaced mine and they have been almost completely clogged. The fuel that goes into the ground at the gas station isn't contamination free. Do you also not replace the oil filter either?

 

I wish I had pictures of the mud I've shoved into pipeline ruptures just so damaged sections could be welded. And every 5-7 years the huge holding tanks fuel is stored in above ground is cleaned and its unbelievable the trash that is those tanks!

Either way, fuel filters need to be changed. When I changed the 2000 Expedition fuel filter, it had 30,000 miles on it from just us, and no idea when it was last changed. When I removed it, the trash that poured out was similar to coffee grounds and was just black.

 

Yes I replace the oil filter at each time I change my oil.
On my 95 truck it has 230,000 miles and I have never changed the fuel filter.
I do carry a new fuel filter & disconnect tools with me in the bed tool box but I have never needed to change it out yet and my fuel pressure is normal.
I see that every body on here that has a fuel problem changes the fuel filter first and they still have the fuel problem.
Some say they find some junk in the fuel filter and if so I wonder what the sock on the bottom of the fuel pump is like. This would also mean junk has gone through the gear pump of the FDM meaning the FDM needs to be changed also.

My motto is if is not broke don't fix it and if you have a problem test first and then divide and conquer.