Fuel pump replacement by cutting through the floor pan?

[myf16]

My 1996 XLT 4WD has only 28 psi fuel pressure and codes that it's too lean for the computer to compensate. The filter is fairly new and there's no vacuum leak, so it's time to replace the pump.

I have read about doing it the right way, lowering the fuel tank:

Fuel pump / Fuel tank - Tips and warnings

My '95 XLT , 2WD, recently died, luckily in my driveway. I had just changed a brake rotor and went to move the truck and it didnt start. Actually made me chuckle: Change brake rotor = kill truck. :scratch: ;) Obviously the two were not connected. So using all the great info from this site...

www.explorerforum.com

1995 -2001 Ford Explorer Fuel Pump Removal and Installation Procedure Maintenance

Then I saw this crude but effective alternative, cutting a hole in the floor directly above the fuel pump:




My XLT has 190k miles but is running strong. It looks beat up and worn out, so I don't mind adding one more mostly cosmetic insult. I can cover the hole afterwards with an aluminum sheeting screwed down. I have the metal fuel line tool, which I bought when I changed the fuel filter. Lowering the fuel tank looks much harder and with higher risk of failure than cutting the floor.

What advice do you veterans have for me?

Edit: I just discovered that I have a steel crossmember above the fuel pump, as someone mentioned in the comments to one of these writeups. So I will need to drop the tank. Ugh.

 

[J_C]

I hate to second guess the diagnosis but if it's consistently producing 28PSI, it seems more likely that you either have a vac leak or a dirty MAF sensor.

There are topics in this forum with pictures, where people have done this by cutting the hole in the floor. I don't recall (could be wrong) a problem with the crossmember. Here's one of them:

FUEL PUMP ACCESS PANEL 95 - 96 ( 97?) FOUR DOOR

Hey gang, Thought I'd post this for anyone interested....I'm not sure if the 97 is in same spot (most likely since same back hatch/ setup) but sure 98 and up are a few inches further back and to the left a hair --and more troublesome due to metal contour. (The part numbers for a 95 versus a 96...

www.explorerforum.com

 

[myf16]

Months ago I used a smoke machine to find minor leaks at the IACV and EGR diaphragm, so I replaced the EGR valve and the idle air control valve. I used MAF sensor cleaner on the MAF, which does look clean. The MAF readings on OBD2 look normal from what I can tell. Less than 30k miles ago I replaced wires. The spark plugs are new. The long term fuel trim is similarly high (15 to 18) on both banks of my 4.0L, so it's not one faulty fuel injector.

I too am puzzled that 28 psi would be too low for the computer to compensate for. I'm open to suggestions to avoid changing the fuel pump, but it seems like I've already done everything else.

 

[J_C]

I might've been mis-remembering fuel pressure. I took a look on Rock Auto and the regulators listed, range from 39PSI to 41PSI, so that's a larger difference than I thought. Another thing I'd wonder about is if the fuel pressure regulator is getting weak.

1996 FORD EXPLORER 4.0L V6 Fuel Injection Pressure Regulator | Shop Now at RockAuto

Fuel & Air Parts and More for Your 1996 FORD EXPLORER at Reliably Low Prices. Fast Online Catalog. DIY-Easy. Your Choice of Quality. Full Manufacturer Warranty.

www.rockauto.com

 

[EB4X]

Our 95/96 4.0s (return systems) are normal at 30 psi. ....32 psi...so 28 isn't significantly low....but I guess could be low enough for issue...? On side note, It's common for OUR 4.0 ohv upper intake (plenum) manifold rubber gaskets to dry out and become brittle / cause leaks after so many years, so if yours are originals those could definitely be suspect imo for your situation as well.

 

[Turdle]

You might get a different pressure reading with vacuum line removed from the regulator. Vacuum decreases fuel pressure. Plug vacuum line while engine is running

 

[myf16]

I have 36 psi with ignition on, engine not running. 28 psi with engine running. 38 psi with engine running and vacuum line pulled off.

I swear when I ran the smoke machine there was no leak anywhere after I replaced the EGR valve.

 

[410Fortune]

Sorry but 28 psi is low indicates a problem
It will run but the fuel won’t atomize properly
Leaving the injectors
Spec is 36-42 psi
32 maybe…28 I would look for a problem in plumbing / wiring and then plan to replace pump with a Bosch

It doesn’t hurt to check your numbers with two gauges
Also I bet when the pump gets hot pressure drops off even lower

 

[myf16]

Thanks for the confirmation. This thread also says 28 psi is too low:

What is the normal fuel pressure at the rail?

I have a 96 explorer 4.0. Using a harbour freight guage I'm showing 29 psi. After the outside temperature reaches 92 degrees my vehicle starts idling very rough and the guage reads 10 psi. So I know I'm having fuel related issues for sure now. I would just like to know what the normal pressure...

www.explorerforum.com

 

[myf16]

Does my 36 psi measurement mean that the fuel pump is capable of maintaining 36 psi but the regulator is dropping it too much? Or is the 8 psi drop with the vacuum connected normal, and 36 psi is too low for a properly functioning unregulated fuel pump?

I have 36 psi with ignition on, engine not running. 28 psi with engine running. 38 psi with engine running and vacuum line pulled off.

I swear when I ran the smoke machine there was no leak anywhere after I replaced the EGR valve.

Sorry but 28 psi is low indicates a problem
It will run but the fuel won’t atomize properly
Leaving the injectors
Spec is 36-42 psi
32 maybe…28 I would look for a problem in plumbing / wiring and then plan to replace pump with a Bosch

It doesn’t hurt to check your numbers with two gauges
Also I bet when the pump gets hot pressure drops off even lower

 

[410Fortune]

It should maintain 36 psi always and rise to 42-45 eith engine running and vaccuum line removed from regulator

It sounds like your pump can make 36 psi and that’s about it. As soon as the engine starts it drops because the pump cannot keep up with the 36 psi and the need to feed the engine.
These pumps dead head at like 60-80psi they should keep the rail pressurized to 36 psi even when demand is high and it’s been running for hours…year after year

Eventually they get weak
It used to be a pump would work or not
These days with the way they are designed they tend to get weak first long before they fail

 

[toypaseo]

On my 96, I had a full tank, so didn’t want to drop the tank. I used a metal cutting wheel attached to my cordless drill. Took a while, but I was unsure of clearance under the body. Ran into two layer body, used hacksaw, channellocks, pliers, etc, etc, and a lot of cuss words…

 

[myf16]

It should maintain 36 psi always and rise to 42-45 eith engine running and vaccuum line removed from regulator

It sounds like your pump can make 36 psi and that’s about it. As soon as the engine starts it drops because the pump cannot keep up with the 36 psi and the need to feed the engine.
These pumps dead head at like 60-80psi they should keep the rail pressurized to 36 psi even when demand is high and it’s been running for hours…year after year

Eventually they get weak
It used to be a pump would work or not
These days with the way they are designed they tend to get weak first long before they fail

This is why I love this site! Authoritative definitive answers.

I will change the fuel pump as soon as I use up the gas in the tank.

 

[410Fortune]

If you cut the access panel then you done have to wait till the tank is empty

 

[Daymon Powell]

My 1996 XLT 4WD has only 28 psi fuel pressure and codes that it's too lean for the computer to compensate. The filter is fairly new and there's no vacuum leak, so it's time to replace the pump.

I have read about doing it the right way, lowering the fuel tank:

Fuel pump / Fuel tank - Tips and warnings

My '95 XLT , 2WD, recently died, luckily in my driveway. I had just changed a brake rotor and went to move the truck and it didnt start. Actually made me chuckle: Change brake rotor = kill truck. :scratch: ;) Obviously the two were not connected. So using all the great info from this site...

www.explorerforum.com

1995 -2001 Ford Explorer Fuel Pump Removal and Installation Procedure Maintenance

Then I saw this crude but effective alternative, cutting a hole in the floor directly above the fuel pump:




My XLT has 190k miles but is running strong. It looks beat up and worn out, so I don't mind adding one more mostly cosmetic insult. I can cover the hole afterwards with an aluminum sheeting screwed down. I have the metal fuel line tool, which I bought when I changed the fuel filter. Lowering the fuel tank looks much harder and with higher risk of failure than cutting the floor.

What advice do you veterans have for me?

Edit: I just discovered that I have a steel crossmember above the fuel pump, as someone mentioned in the comments to one of these writeups. So I will need to drop the tank. Ugh.

 

[Daymon Powell]

Just did this ,you don't have to pull the tank just drop it down and then you can acres the pump.I used jack stands be liberal w / PB blaster
Good luck

My 1996 XLT 4WD has only 28 psi fuel pressure and codes that it's too lean for the computer to compensate. The filter is fairly new and there's no vacuum leak, so it's time to replace the pump.

I have read about doing it the right way, lowering the fuel tank:

Fuel pump / Fuel tank - Tips and warnings

My '95 XLT , 2WD, recently died, luckily in my driveway. I had just changed a brake rotor and went to move the truck and it didnt start. Actually made me chuckle: Change brake rotor = kill truck. :scratch: ;) Obviously the two were not connected. So using all the great info from this site...

www.explorerforum.com

1995 -2001 Ford Explorer Fuel Pump Removal and Installation Procedure Maintenance

Then I saw this crude but effective alternative, cutting a hole in the floor directly above the fuel pump:




My XLT has 190k miles but is running strong. It looks beat up and worn out, so I don't mind adding one more mostly cosmetic insult. I can cover the hole afterwards with an aluminum sheeting screwed down. I have the metal fuel line tool, which I bought when I changed the fuel filter. Lowering the fuel tank looks much harder and with higher risk of failure than cutting the floor.

What advice do you veterans have for me?

Edit: I just discovered that I have a steel crossmember above the fuel pump, as someone mentioned in the comments to one of these writeups. So I will need to drop the tank. Ugh.