New to the V10.. Low fuel pressure

tropical36 wrote:

You might be better off with getting an OEM replacement and hopefully you can return the one you have now. Try Amazon first, then maybe Mills supply, along with many others for a discount over your local Dealer.

Thats where my frustration is from. This IS a factory Ford Motorcraft complete pump assembly in the factory box and it won't work. Cost $600 over the others that were 1/2 the price but I figured it was worth the added expense. How much you wanna bet the aftermarket one would have been just fine and I'd be done.... :-(

Jrork wrote:

tropical36 wrote:

You might be better off with getting an OEM replacement and hopefully you can return the one you have now. Try Amazon first, then maybe Mills supply, along with many others for a discount over your local Dealer.

Thats where my frustration is from. This IS a factory Ford Motorcraft complete pump assembly in the factory box and it won't work. Cost $600 over the others that were 1/2 the price but I figured it was worth the added expense. How much you wanna bet the aftermarket one would have been just fine and I'd be done.... :-(

OK, my bad and I keep forgetting that we're talking Ford here and Motorcraft is a product of Ford.
So, does the old unit have any kind of part number on it?
Here's another idea, without actually seeing the thing and I once changed the fuel pump in a Mazda, but not the whole assembly. Just the pump itself (aftermarket in this case) and I think the way to go, as long as the pickup tubes....etc...are in good condition. Also, as food for thought, while you're inspection things, I found that the real problem was that the electrical connector inside the tank for the unit was burned pretty bad and being that it was only available with the whole unit, I made up my own connector and one that wouldn't ever fail. Had the car for years after, my cousin owned it for awhile and it was still going good, when he sold it.

...

Another vote for seriously considering using the old sender/mount hanger assembly and just replacing the pump cartridge. Although most net searches will return a variety of brands of pump, I believe most OEM get their pumps from a root manufacturing source called Walbro (a USA pump manufacturer) and put their own sticker brand on it.

All the pump has to do is pump enough to support the HP range. Your V-10 has around 300HP and it takes a certain amount of gas to achieve that over a 4 cylinder for instance. That 300 HP puts you in the range of a common 255LPH (255 liters per hour) pump which will support up to 500HP. The excess fuel is returned via the regulator and return line, or the pump voltage is adjusted/pulsed to furnish what is needed, very little at idle, a moderate amount at mid-throttle for instances. Modern F.I. may seem complicated but it is far from rocket science and all world vehicles now use essentially the same tech for port injection (such as the V-10).

Such pump cartridges may sell direct for little over $100 and, being an OEM supplier, Walbro has always been top quality in the past.

As an example, here is a Walbro 2003 F550 V-10 pump for $108. All 2 valve V-10's are similar HP and the small-truck-only 3-valve HP are just a bit above at around 360 HP, both V-10's same size pump catagory however.

You will probably find that your Motorcraft cartridge will fit by itself if you cannibalize the new one and want to blow the big bucks on it. Otherwise you should be able to find Walbro pumps here: walbrofuelpumps.com. $99.99 with free shipping.

Good luck.

P.S.
I forgot to mention that some gas tanks when left parked for a long time (without adequate fuel submersion) tend to rust the fuel level sender which is usually part of the hanger assembly. In that case your fuel guage may be inaccurate and you will benefit from finding a new hanger, or at least proper parts to replace the fuel level indicator part.

Wes
...

I recently replaced my fuel pump/sending unit assembly on 2002 F53 with V10 engine. The Motorcraft #F7UZ-9H307-DC (PFS-66). To my best knowledge this pump is made by Delphi and a replacement pump only is available for around $80.

You should take a fuel pressure reading with the return line clamped shut with a vise grip. This will tell if the pump is bad.

Could it be you fuel system check valve(in the pump) is bad, letting fuel drain back, and that is why you have the long crank times.

You said specs were 30 - 45 right?

Also, never replace a electric fuel pump without first checking voltage drop with a digital multimeter.

To do a voltage drop check:

- Jumper the fuel pump on at the relay.
- Take a long jumper wire lead and hook it to battery POS.
- Hook you meter neg to the long jumper lead.
- Hook you meter pos to the feed(pos) terminal at or near the pump.
- Your volt reading on the meter should be .05 or less.
- A higher read means the wire to the pump is bad.

You can do the same procedure for the fuel pump ground.

You can find this explained here:
Schrodingers Box - Youtube auto repair help
and here
ScannerDanner - YouTube Auto Repair

Never use a test light on a computer driver circuit.(You can fry it. Use a DVM only. This is computer driven.)

What that said, I think you do have a bad fuel pump. It should hold fuel pressure when off.

I did find this:
Article for Ford Chassis hard start diagnosing.

Wes Tausend wrote:
...

Another vote for seriously considering using the old sender/mount hanger assembly and just replacing the pump cartridge. Although most net searches will return a variety of brands of pump, I believe most OEM get their pumps from a root manufacturing source called Walbro (a USA pump manufacturer) and put their own sticker brand on it.

All the pump has to do is pump enough to support the HP range. Your V-10 has around 300HP and it takes a certain amount of gas to achieve that over a 4 cylinder for instance. That 300 HP puts you in the range of a common 255LPH (255 liters per hour) pump which will support up to 500HP. The excess fuel is returned via the regulator and return line, or the pump voltage is adjusted/pulsed to furnish what is needed, very little at idle, a moderate amount at mid-throttle for instances. Modern F.I. may seem complicated but it is far from rocket science and all world vehicles now use essentially the same tech for port injection (such as the V-10).

Such pump cartridges may sell direct for little over $100 and, being an OEM supplier, Walbro has always been top quality in the past.

As an example, here is a Walbro 2003 F550 V-10 pump for $108. All 2 valve V-10's are similar HP and the small-truck-only 3-valve HP are just a bit above at around 360 HP, both V-10's same size pump catagory however.

You will probably find that your Motorcraft cartridge will fit by itself if you cannibalize the new one and want to blow the big bucks on it. Otherwise you should be able to find Walbro pumps here: walbrofuelpumps.com. $99.99 with free shipping.

Good luck.

P.S.
I forgot to mention that some gas tanks when left parked for a long time (without adequate fuel submersion) tend to rust the fuel level sender which is usually part of the hanger assembly. In that case your fuel guage may be inaccurate and you will benefit from finding a new hanger, or at least proper parts to replace the fuel level indicator part.

Wes
...

Good post and interesting that you mentioned Walbro, which was the brand I used on my Miata replacement.

Here's the last update. Once we removed the pump we found the rubber hose from the actual pump to the sending unit housing was in horrible shape and was deteriorating. The bottom of the tank had all sorts of pieces of rubber from it and what was left of the generator pick up too. It too was falling about in my hand. Swapped out the pump and shazaam, it fired right off and holds pressure versus how it use to be where the pressure would bleed off almost instantly after you turned the key off. Thanks again everyone

Fuel line used inside a gas tank needs to be SAE 30R10 rated. It's expensive and tough to find. Regular high pressure hose will deteriorate.

Gates submersible fuel line

Jrork wrote:
Here's the last update. Once we removed the pump we found the rubber hose from the actual pump to the sending unit housing was in horrible shape and was deteriorating. The bottom of the tank had all sorts of pieces of rubber from it and what was left of the generator pick up too. It too was falling about in my hand. Swapped out the pump and shazaam, it fired right off and holds pressure versus how it use to be where the pressure would bleed off almost instantly after you turned the key off. Thanks again everyone

Did you end of just replacing the pump or the whole fuel pump assembly, what part did you use?? where did you get it?

Thank you for reporting back the solution. We will all learn from it.