Fuel pump?

[idontknowwhatimdoing]

I recently replaced the fuel pump on my '96 4.0. It had a 1/4 tank of fuel and I did not immediately fill the tank after. Within 3 miles the fuel gauge showed empty and "check gauge" light came on dash. Never a problem before. Went back to aamco and they said fill tank and see if it continues. I did, and it has. When tank gets down to 1/4 the gauge invariably shows empty and "check gauge" light comes on. And now I have the "check engine" light, comes back as "system lean bank one". Do not remember exact wording, should have took a picture, I know my memory sucks. Eventually. Could they be related? I've contacted aamco and they seem amicable, bring it back and they will investigate. But I'm in Washington State on the Olympic coast and aamco is in Carson City, NV. thought I'd change my plugs, been a few years anyway and it wouldn't hurt. Any ideas/advice? Bad idea to drive too far before diagnosing fully?

 

[Josh B]

Why do you need Aamco to fix it?

 

[Josh B]

I've known people to keep up with their gas added and mileage to know how much is in it

 

[RonD]

I am assuming the whole fuel pump Assembly was replaced, that includes the float and fuel level sender
Do you known the brand that was used?

Could be they never adjusted the float arm for the tank size, Rangers had 17gal tank or 20gal tank
With assembly out of the tank and sitting on flat ground the float should be hanging about 2" from the ground
That should give you about 1 to 2 gallons left at EMPTY, a "reserve"
So if the float arm wasn't adjusted and it's at it's lowest 6" above bottom of the tank then EMPTY at 1/4 tank


Lean code does not mean the engine is actually running Lean, so its fine to drive that way
Lean code means computer is opening the injectors longer to get the O2 sensors to read correct voltage

On a V6 engine there are 2 Banks, Bank 1 is passenger side, Bank 2 is drivers side
Yes EXACT CODE NUMBER IS NEEDED, not its definition, THE NUMBER is what you want/need

Partial Ford Code list here: https://www.therangerstation.com/tech/obd-ii_trouble_codes/

There are literally thousands of codes and each means something different, and this is not all of them, just the more common ones


If new fuel pump was acting up then you would get Lean Codes on BOTH banks of the engine

O2 sensors are THE ONLY sensors that wear out, they are like tires or brakes and get used up, 12 years or 100k miles and you need to replace them, so they last a lot longer than tires or brakes but they still wear out
And a worn out O2 sensor WILL CAUSE Lean code on one bank

 

[idontknowwhatimdoing]

Thanks Ron. P0171 is the code.

The gauge off doesn't worry me itself, although I would rather have it work properly since I paid for it to be done, properly. But then searching the web for guidance consistently brought up the fuel pump as a top option for the system lean. And admonitions to drive no further than necessary. So being a natural worrier...

I should just ignore the web. You search "headache" and you find out you have a fatal tumor.

 

[RonD]

As said, on a V6 engine the fuel pump feeds both sides/banks, so you should have
P0171 System too Lean (Bank 1)
and
P0174 System too Lean (Bank 2)

Both sides would be lean if it was a fuel pump/pressure issue
or
MAF issue
or
Upper intake vacuum leak

Only one side lean, points to a lower intake vacuum leak on that side or O2 sensor starting to fail
or you have a misfire on that side which you didn't mention