Does the HP fuel pump on a 1988 F150 5.0L have a check valve?


Asked by Jul 29, 2014 at 08:28 AM about the 1988 Ford F-150

Question type: Maintenance & Repair

My 88 F150 seems to be losing prime (or it's boiling off) when I shut the engine off for a
short period.  If I cycle the ignition switch 3-4 times all is well.   Is there a check valve in
the HP pump.?

16 Answers


I'm sure that there is. Sounds like yours isn't working. A vapor lock isn't likely.

1 of 1 people found this helpful.

Check fuel pressure regulator,may be bad.

1 of 1 people found this helpful.

Both pumps have check valves and they are internal so they can't be serviced, I would be thinking more towards the fuel pressure regulator as stated before, they are considered high fail. You might also check to see if it belches out some black smoke when it is restarted, that would indiacate a leaking injector or injectors.

1 of 1 people found this helpful.

Regulator fine. No smoke. Engine runs like a top (125,000 actual miles) accept hard to start after a short stop.

2 of 2 people found this helpful.

What is your fuel pressure?


No way to check that. I am aware of the check valves on the pumps in the tanks. Since both tanks act the same way, I suspect there is a checkvalve in the HP pump. I seem to recall reading that somewhere.


You could bite the bullet and replace the high pressure pump, then if that didn't fix it then replace the regulator.


But I'd do it the other way, replace the reg first.

1 of 1 people found this helpful.

I have replaced the regulator. I will replace the HP pump next week.


A retired Ford mechanic told me that Ford tried to make the dual tank system work with several different schemes, but never was truly successful. My dad had a 69 3/4 ton Ford that had 2 tanks. The switching mechanism consisted of a manual valve on the floor left of drivers seat, and toggle switch on the dash to switch sending units. This system worked, but you had to remember to throw both the valve and the switch. Ford finally gave up and went to one tank- but larger capacity. Duh!!!!! And they got rid of the tire wrecking Twin I Beam too. Duh!!!!!! I got a recall notice on my 2012 Taurus today. It seems the license plate light cover can be affected by road salt, and cause a fire. Things never change.


And, I had a 92 F150 with the same darn transfer fuel from tank to tank issue. Ford installed check valves in the fuel lines. Seemed to cure it.

1 of 1 people found this helpful.

And it's only going to get worse, I've decided to never buy a new vehicle again, this protectism and connectivity garbage will stop someday but by then I most likely won't care any more or be dead.


Had the HP fuel pump replaced today. It seems to have fixed the problem. Now the water pump went out!!!!!!!


OUCH! It never rains, it pours.


now if it follows suit the oil pump will start acting weird just before it fails


These things come in threes.

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