2005 Ford Focus - Fuel Pump Check Valve

[shima]

Hi guys!

My girlfriend's Focus has a pretty bad hard start...

We took her car to a shop right by our house, and they diagnosed it as a bad check valve in the fuel pump assembly. They told us that the check valve is supposed to hold 40psi of fuel after the car is shut off, and that her's is storing ~5psi!! Hence the hard start.

Now, the unfortunate part... they quoted her $950 for the fix. I don't scoff at that number at all because the fuel pump assembly is inside the gas tank, and replacing it sounds like a major pain in the ass. They said 4.5 hours labor + cost of parts = $950.

My question is probably impossible to answer, but I want to know if anyone can take a guess at how long our fuel pump might last if we don't have this work done? I told her that if we keep the gas tank full and we let the fuel pump build pressure before cranking it then we might get another year out of it. I pulled that out of my ass, though.

Anyone else out there have a Ford Focus in their family with a similar issue?

 

[mrk5]

I was thinking the same thing as you. If the diagnosis is accurate, you can try turning the key on and let the pump run for about 15 seconds. I don't know if it would really shorten the life of the pump anyway. I think they may reason they would have the check valve is because people now a days expect to get in and have their cars start right away. Most people don't remember what it was like in the carburetor days.

 

[Joe In Montana]

The pump itself is MAYBE OK for a while using it this way - and what you're planning on doing won't lower it's life expectancy at all.

The check valve isn't working when the pump is running, it's just letting fuel go past it on the way to the engine - so it's normally 'pushed out of the way' during normal operation anyway.

BUT - and here's the rub - if you let the tank get below 1/4, then you may be damaging the fuel pump - since it needs to be charged with fuel and it needs to be under the fuel level to properly cool and lubricate the bearings.

YES - the fuel pump bearings run on gasoline as their lubricant. Interesting huh?

This is why I always told my customers to NEVER let the tank get below 1/4 full - as that damages and shortens the life of the pump every time it is high and dry, out of the fuel level.

Personally I feel that the price they quoted you was a tad high - by about $300.00 .... but I've had a few years retirement to forget some of the prices I charged when I had my shops. Maybe Denver is high pockets.

 

[shima]

@Joe In Montana thanks man! I had no idea that the fuel pump needed to be submerged. That explains why it is inside the gas tank, I guess. Cheers!

 

[Joe In Montana]

Actually - putting the pump inside the tank is for another reason.

These pumps run [lineout]somewhat[/lineout] significantly higher pressures than the old - mounted-on-the-engine-and-operated-by-a-pushrod suction style pumps. Those were really for carburetors, not fuel injection.

The idea was to help prevent fires and vehicle immolation if the pump leaked high pressure fuel. "Encase it in the tank" was the idea to help prevent crispy critters and a whole lot of bad PR for the manufacturers. It kept them outta the papers and off Ralph Nader's cr@plist and product liability attorney's fees to a minimum.

That it gets lubed and also cooled by living inside the tank is a by-product, although a very necessary one.

IIRC - One interesting anachronism: F**d tried inside and outside (frame-mounted) pumps in their dual tank trucks. Again - and I'm calling up some really old gray matter here - the inside-the-tank low pressure pumps were what ran after the engine was started and the frame-mounted pump was for the initial startup purge and higher pressure to get the system charged with the necessary fuel to start the engine.

Here's the frame mounted High Pressure Boost pump on a F-150 P/U:


At start-up, you ran both pumps - the frame unit and one of the tank units. After the engine was up-n-running and stabilized, the frame pump shut off and the injection relied on the tank pump only.

It looked good on paper to the F**d bean counters and cubicle engineers - but was fraught with troubles because owners who didn't know any better would just replace the boost pump when they had troubles and had no idea there was a tank pump too.

Below is a typical 88-90 F-150 in-tank pump (low pressure)



If the vehicle for some reason needed boost in fuel pressure at any time - the frame pump could be called into operation by the ECM. Go figger!

Gawd! I miss F**d engineering for my income! MoPaR too!