88 2.9 Ranger just died

[englewoodcowboy]

My kids truck has stranded him yet again and I believe it to be fuel related. What I am finding is air in the fuel rail. Its building pressure but when you open the shrader valve it is blowing air then fuel. If you bleed it long enough to get solid fuel it will run for a few seconds then die.

Here is what has been done recently in the past:

New in tank fuel pump
New fuel filter
New pressure regulator

Here is what we know:

It builds fuel pressure but it is not stable, the motor will not stay running and the fuel rail has air.
Full tank of fuel.
Both pumps are running when the key is cycled.
No visible leaks from the tank to the fuel rail.

My thoughts;

The only place I can guess it would be ingesting air would be the second in-line fuel pump. If it had an opening between the two pumps we should see a leak as well as between the second pump and the fuel rail. Any ideas? The in-line fuel pump is origional and I have never had it out to inspect it, could it be cracked and ingesting air and pumping that into the system?

 

[PanamaExpat]

Does it have the famous quick connects? I could see a bad o ring causing something like that. Pressure no leak... suction... draws air in past bad o ring.

 

[englewoodcowboy]

It does have the orings but more info. It cooled down, fired right up. Solid fuel flow no issues. I talked to my son and asked if it was hot, he was running the air conditioning and it was up to the O he said on the temp gauge. Now I am thinking vapor lock but thought that is not supposed to happen on a return fuel system which now makes me think it is not returning properly, since I recently replaced the fuel pressure regulator, and all the parts coming from crapina I am starting to think it is faulty. When the fuel starts to vaporize it will also cause a lean condition and cause the temp to rise. Give me some advice here guys. Thanks!

 

[fyre82]

Try to recreate the condition it was in when it stopped.

Practice the basic safety stuff, set the brakes, block the wheels, etc. and do it in the yard.
I use a piece of cardboard over most of the radiator when I want a faster warmup or test thermostat function. You can block the throttle to simulate highway speed. Turn on the a/c. Just watch it so you don't over heat. Don't forget to remove the cardboard when you are finished.

That will give you a chance to roll around under to see if something is getting heated that shouldn't, do the wiggle tests on connections and allow you to observe the engine as it runs and warms.

Good luck.
Rich

 

[a31ford]

An injector stuck open (or spastic), will cause air bubbles.

Greg

 

[RonD]

I would cycle the key on and off, fuel pump should run for 1 or 2 seconds each time you do that, then check rail for air, repeat until there is no air.
Then cycle key a few more times, now look for leaks.

It would be nice to put a pressure gauge on the rail to watch the pressure.

Also I know my kid's cars never have over a quarter tank of gas, lol.
No use hauling all that extra weight around town

Anyway what about testing it with a full tank, could be the new pump line in the tank isn't sealed, so air, above fuel level is getting in, full tank would prevent that.

But my guess would be the inline pump as well, original equipment, 25 years old now, could be time to change it.

 

[wildbill23c]

Have you checked for fuel leaks after the fuel system parts replacement. Its pulling air in somewhere to have air at the fuel rail. Let it cool completely and start it up on a flat surface, either place cardboard along the underside where the fuel line connections are, or park on a concrete surface. Start the truck and let it just idle check for fuel leaks as it is idling. Sometimes after replacing parts if you don't clip the ends of the rubber fuel lines before re-installing stuff they can leak and in the case of a pressurized fuel system with the fuel injection it can cause air to get into the system.

 

[doorgunner]

My swimming pool pump had the same problem......

Hold on......I'm serious.......

The main pump would fill the filter canister with air pressure and water....

I found 2 problems.........the inlet was partially blocked with trash and the pump impeller had a small amount of trash caught in it.....

it was cavitating causing it to pump more air than water...

(of course....I'd drop the tank as a last resort)