Troubleshooting A Fuel Starvation Problem

[mlochala]

I have a '98 Mountaineer with the 5.0 V8.

Recently I replaced the fuel pump. Also, when I replaced the fuel pump, I replaced the much hated quick snap fuel lines with high pressure rubber lines and much more easy to use worm gear clamps. Everything went well with no issues. The inside the tank looked surprising clean for a 13 year old vehicle with about 160,000 miles. I had no issues reinstalling the tank or the new pump.

However, in the week since this has been done, a new problem has popped up. Now, when the gas gauge shows 1/4 full, the vehicle will occasionally stall as if it is starving for fuel. But, the warning light does not come on and the gauge still shows about 1/4 full. If I add any fuel to it, the problem goes away, at least until the level drops back down again.

As I said, everything reinstalled fine. I was careful not to bend or damage the sending unit. I also installed a new fuel filter and of course a new strainer. The pump is an Airtex from Autozone.

I have't yet gone back into this thing, but any ideas on what could be happening here? Could it be a venting issue?

 

[drdoom]

I don't know, but my Explorer won't hit a lick at one quarter tank + slightly downhill. YMMV

 

[EvilExplorer5.0]

Weird...
I just swapped a fuel pump assembly out in my '99 5.0, and when I started it back up, there was less than a ½ gallon in the tank, AND there were still jackstands under the rearend, and it started up and ran perfectly!
....until one of the ignition coil packs melted. :-/

 

[mlochala]

I don't know, but my Explorer won't hit a lick at one quarter tank + slightly downhill. YMMV

I think that is actually related to my problem. I took it for a ride earlier today and I noticed that when it happened it was either on downhill portions of the road or if I stopped quickly at a stop sign.

What I'm guessing is that for some reason the pump is not reaching deep enough and when the gas sloshes forward (like when going down hill or coming to a stop) it's just not able to grab enough fuel. And that is strange because it appeared to mount exactly the same as the original one.

Any other suggestions?