[G8orFord]

You would remove the feed line at the fuel bowl and adapt a way to put a pressure gauge directly on the line. If you're only getting 22 psi directly from the line, then you either have a problem with the pump or the delivery between the tank and the bowl. The test port is post regulator. You'll only see the regulated pressure, not what the pump is actually putting out. If you're getting +60 psi directly from the line, you've got a regulator problem.

The easiest way to rule out a pickup tube or feed line problem would be to remove the feed line from the tank at the pump and fab up a line to an external tank and see if the pressure problem persists.

 

[nighthawk285]

Ok, so I got home and hooked the manual gauge linked this morning by G8orford into my fuel pressure port and guess what....... 22psi idling dropping down to around 17 or so driving under demand.

Unless the fuel pressure regulator, spring inside it or something else is messed up, it’s time for a fuel pump.

Found the Ford Fuel pump and Ford blue spring on Amazon today about $360 for both, free shipping.

Unless y’all got other suggestions, ordering tomorrow.

Thanks,

TXPower

I'd probably try to verify line pressure first and possibly redo the blue spring before I replaced the pump, but it's your money. Adapting something to fit the line at the fuel bowl may be more work than just replacing the pump and regulator. Something else to consider is that it may be getting air in the system from a pinhole in the pickup tube or a connection. That would affect pressure as well.

@nighthawk285 is the expert though.

I'm far from "expert" but thanks. There's always more to learn.

IMO if you have two independent gauges that have the same readings like that, you likely have an issue and yeah, either have a weak pump or a big restriction somewhere. If you have no big driveability issues I'm going with a weak pump.

The nice thing about verifying against a mechanical gauge like that is that USUALLY you can also see the needle swing hard or wiggle in smaller increments that sometimes get normalized with an electronic gauge and sending unit. A 1-3psi constant wiggle would have me diving harder to find an air leak, but since you don't seem to have that it looks like you're on the right track with going with a new pump and regulator.

I too would replace the regulator first and then test again before swapping the pump...... at that point it doesn't cost you anything but the extra time and you may find a bad o ring or something at the fuel bowl that could be attributing.

 

[TXPower]

I'm far from "expert" but thanks. There's always more to learn.



IMO if you have two independent gauges that have the same readings like that, you likely have an issue and yeah, either have a weak pump or a big restriction somewhere. If you have no big driveability issues I'm going with a weak pump.



The nice thing about verifying against a mechanical gauge like that is that USUALLY you can also see the needle swing hard or wiggle in smaller increments that sometimes get normalized with an electronic gauge and sending unit. A 1-3psi constant wiggle would have me diving harder to find an air leak, but since you don't seem to have that it looks like you're on the right track with going with a new pump and regulator.



I too would replace the regulator first and then test again before swapping the pump...... at that point it doesn't cost you anything but the extra time and you may find a bad o ring or something at the fuel bowl that could be attributing.

G8or, Nighthawk, thanks. I’ll replace the regulator with upgraded blue spring first. If low low pressure persists, I’ll move to the pump.

Thx,

TXPower

 

[TXPower]

G8or and Nighthawk, do you think I could pull the line off the fuel pump that goes from the pump to the upper Fuel Filter bowl, put a piece of hose and clamp on it and plumb my manual pressure gauge to it and measure the pressure the pump is making that way?

While I had that fuel line disconnected, could I unhook it up top at the upper fuel bowl and run compressed air through it to make sure there are no obstructions between?

Thoughts?

I’m ordering the Blue Spring Upgrade today.

Thanks,

TXPower

 

[G8orFord]

Yes, you can do that.

 

[nighthawk285]

G8or and Nighthawk, do you think I could pull the line off the fuel pump that goes from the pump to the upper Fuel Filter bowl, put a piece of hose and clamp on it and plumb my manual pressure gauge to it and measure the pressure the pump is making that way?

While I had that fuel line disconnected, could I unhook it up top at the upper fuel bowl and run compressed air through it to make sure there are no obstructions between?

Thoughts?

I’m ordering the Blue Spring Upgrade today.

Thanks,

TXPower

Well yes you could, but since the regulator is now out of the equation, the pump would likely just build pressure while it runs until the hose pops off. It wouldn't be a perfect test but it would show that the pump is at least capable of providing the PSI. Value for the pump to secondary fuel filter PSI is 50psi.

The restriction if there is one (or possible aeration spot) is more likely to be on the suction side of the pump and in the tank. Yes you can blow air through the fuel line from the pump to the engine, but I wouldn't expect to see anything come out of there other than diesel.

 

[TXPower]

Well yes you could, but since the regulator is now out of the equation, the pump would likely just build pressure while it runs until the hose pops off. It wouldn't be a perfect test but it would show that the pump is at least capable of providing the PSI. Value for the pump to secondary fuel filter PSI is 50psi.

The restriction if there is one (or possible aeration spot) is more likely to be on the suction side of the pump and in the tank. Yes you can blow air through the fuel line from the pump to the engine, but I wouldn't expect to see anything come out of there other than diesel.

Ok, thanks Nighthawk. Next logical question then. How do I diagnose whether I have aeration occurring between the tank and the fuel pump?

Thanks,

TXPower

 

[nighthawk285]

A couple different ways:

Sound......you can hear changes in the pump when it's sucking air

Sight......if you just run with a hose onto the FP into a bucket you'll see massive variations in the flow accompanied by a lot of air bubbles in the fuel stream

Taste.......no just kidding :thumb:

 

[TXPower]

A couple different ways:



Sound......you can hear changes in the pump when it's sucking air



Sight......if you just run with a hose onto the FP into a bucket you'll see massive variations in the flow accompanied by a lot of air bubbles in the fuel stream



Taste.......no just kidding :thumb:

If it’s an aeration issue will it aerate the the fuel all the time or only when the tank level gets to the perforation or break or whatever the problem is with the pickup tube? If there is a problem there.

Thanks,

TXPower

 

[nighthawk285]

Only when the level gets to that certain point where it can suck air. If there's a break in the pickup tube or anything like that but it's still covered in fuel, there's no aeration.

That all being said, I think we're about 3 steps further ahead than we need to be but it's a good conversation.

 

[TXPower]

Ok, blue spring in, new Ford Fuel Pump in. Result:

63psi cruising at 80mph. 65 to 66 idling. WOT it dropped to like 55psi.

So for those reading this down the road. The sensors I linked from Amazon in the very first post of this thread were fine, work great. Second, the oil pressure gauge that G8orford linked, the 2nd of the two, I should have bought when I first questioned the accuracy of the amazon sensors and strength of my old fuel pump. Lesson learned.

It’s got a little more noticeable pep with new fuel pump and blue spring.

Thanks to all that helped and hope this helps others down the road.

TXPower

 

[nighthawk285]

Thanks for updating with the final conclusion! Glad to hear you're back up and running well!

 

[jokester00]

Good deal! I thought you might feel a bit of a difference :grin:

-jokester

 

[villestrip]

I bought the glow shift fuel pressure adapter. Do you just install it with the o ring or do you have to put Teflon tape on it also?

 

[TXPower]

I bought the glow shift fuel pressure adapter. Do you just install it with the o ring or do you have to put Teflon tape on it also?

If your talking about the fitting they sell that goes into the test port on your fuel bowl, yes, just thread it in and snug it up good. Don’t over tighten it. The o-ring seals it. Teflon isn’t necessary. At least it wasn’t for me.

TXPower

 

[villestrip]

Thanks for the tips in this thread. Just got mine installed using the ebay transducer. I'm around 68-70 at idle drops to 58 at WOT. Took a while to do cause the o ring tore on the brass drain plug. Here's my setup using a 45 degree fitting to move it away from the radiator hose.

 

[Ditch Baby]

Is there a more desirable place to mount this sensor? As in is it better in this test port or on the top of say the bullet proof diesel caps with test port on top?

 

[TXPower]

Thanks for the tips in this thread. Just got mine installed using the ebay transducer. I'm around 68-70 at idle drops to 58 at WOT. Took a while to do cause the o ring tore on the brass drain plug. Here's my setup using a 45 degree fitting to move it away from the radiator hose.

Where’d you get that 45 at?

TXPower

 

[villestrip]

This is the one I got.

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/371010758195

 

[TXPower]

This is the one I got.



https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/371010758195

Thank you sir,

TXPower