In tank fuel pump

[CarlosE]

Hi guys
1986 Bronco II
Just purchased was told it only needed fuel pump. Replaced the pump and it fired right up. Around 5 minutes of run time and it failed again. Upon initial replacement I could hear the front and in tank pump run. Upon failure I could only hear the front pump. Replaced in tank again and again, it fired right up. After a few minutes it failed again. Still hear the front pump. Ran the jump wire to be sure it wasn't the relay. Front pump ran continuously, and the bronc wants to start but just doesn't have enough fuel. Help?

 

[G-Dirty]

Could you have a bad connection somewhere in between the in tank fuel pump and battery? I would use a multimeter to ohm in between the two when it isn't working.

Also, when you replace the in tank fuel pump, do you hook it up to power to confirm that it doesn't work?

 

[kaidenshi]

I'm having a similar issue. My 1988 BII sat for about three years with a dead engine, I put a good used engine in it and it drove fine for a few hundred miles, then it would end up fuel starved after running for a few minutes and shut itself off. I could crank it right back up and go for a few more minutes before it died again. I dropped the tank and found it to be rusty inside, and I replaced it with a new tank, new fuel pump and sending unit, and fresh gas. I also replaced the inline filter between the high pressure pump and the engine.

It drove like new for a couple hundred miles, but now it's showing similar symptoms to what it was doing before, just not as severe. It will bog down for about 10 seconds at moderate acceleration, and when slowing to a stop it will start trying to cut out on me. I can tap the gas pedal and it goes away, or shut it off and back on and it's fine again. I put new injectors on it since the old ones seemed rough, but it still does it. I'm guessing that maybe the high pressure pump is bad too, or maybe the fuel pressure regulator? It seems to get plenty of pressure at the rail, and the issue only lasts for about 10 seconds at a time.

 

[TonyStarks423]

Fuel lines. Theres an inner and outer part of the fuel lines and if the inner is leaking to the outer it will slowly decrease fuel pressure until the fuel line collapses on itself and starves the engine. When you take pressure off the lines to change the pump the lines open back up, giving you a few more hundred miles.

Just a theory, id check the fuel lines next time to ensure they aren't collapsed.

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