3.0 Engine Squeal

[snbolson]

Now here is one to make you scratch your head. 2001 Ranger 3.0L squeals when the gas is below a quarter of a tank. I thought belt squeal and have replaced belt with a gator back belt, both idler and tensioner pulleys. The tensioner itself. I have listened with a stethoscope and have no noise from the cam position sensor, alternator, power steering pump, water pump or airconditioner. I checked crankshaft end play (.012). No change in injector noise. If you fill the gas tank about a quater the squeal goes away. The noise sounds like it is coming from the right front side of the engine. There is no noise coming from the fuel tank other than normal fuel pump running noise. I changed the fuel filter just to eliminate it from the problem. I'm at a loss what this could be.

 

[fixizin]

Is it running fine otherwise, at all RPMs and loadings? No Check Engine light?

Simply a wild-@ssed guess (WAG), but the vacuum-operated fuel-pressure reg is up top towards passenger side... also gauge is notoriously inaccurate down in the low end... so maybe you have way less than 1/4 tank when it says 1/4... fuel pump is getting inadequate cooling and/or is picking up air somehow... you're hearing the result at the point in the fuel loop where high-pressure becomes low-pressure...

I really don't know, but I'd be putting a fuel pressure gauge on the Schrader valve, also right front portion of engine top fuel rail, just foward of fuel pressure regulator... see if pressure changes from squeal state to quiet state.

 

[snbolson]

The truck runs fine and no check engine lights or codes. I have had the truck since 2002 and it takes the right amount of gas to fill it up for a quarter tank. I'll put a fuel gauge on it this weekend and monitor it. I just filled it up with gas on the way home so it will take me a while to get down to the quarter range again. Thanks for the suggestion.

 

[snbolson]

Sorry for not posting a fix earlier. Fuel pressure was 65 while driving. It never changed when the squeak started again. I checked over everything I previously had tried but I kept going back to the tensioner. I bought one from Ford this time and wall ah, the squeak is gone. I must have gotten a weak after market one. I am glad to put this one to bed.

 

[Jspafford]

So what's it have to do with the amount of fuel in the tank?