2000 3.0 L Mysterious Fuel Leak

[Jeide]

The good news is that I may have found the source of my P0443 trouble code. My truck has been running great ever since I replaced the engine a year ago. The other day, on my way home, I stopped by the store for a couple of minutes and when I went to leave, the truck would not turn over. I started checking the electrical and noticed a strong smell of gasoline from the engine compartment. I looked around and thought I saw a break in the hose connecting the fuel rails. I was wrong, what I saw was a broken piece of hose not attached to anything but sitting in the same area. Since I had it apart, I replaced the upper intake manifold gasket and injector orings. When I got her back together, I got her to start but running very rough with occasional blue smoke and a drop in power. The fuel pump runs. There was fuel coming from the vacuum hose connected to the fuel damper which indicates a break in the dampers diaphragm. I will be replacing that. When I pulled the other end of that vacuum hose from the nipple at the rear of the intake manifold a significant amount of fuel came out making me wonder if the manifold was the source of the leak. Is this possible? There is also a smell of gasoline to the oil on the dipstick which indicates an injector stuck open. Right now I can get her to start. When I turn the key, the fuel pressure barely registers. I vacuum tested the damper and the gauge would go up but quickly fall to zero. But I can't rule out the possibility that my Mickey Mouse gauge setup might be leaking. My main question is could there be any other way for fuel to get into the intake manifold vacuum other than from the damper? Any other things that I can check for? I understand that the fuel pressure regulator is in the tank. Could a problem there be causing any of this? Thank you in advance for any help that you can give.

 

[pjtoledo]

if the fuel filter has 3 ports it has an internal regulator.
is this a flex fuel Ranger? they have a very expensive alcohol sensor forward of the filter.
testing the vacuum gauge is easy, just plug the hose.
a broken diaphragm will feed fuel to the intake. with 20 psi of intake vacuum at idle the intake can suck a lot of fuel out of the damper.

 

[Jeide]

is this a flex fuel Ranger? they have a very expensive alcohol sensor forward of the filter

Thank you pjtoledo and Ron. Yes, it is the flex fuel variant. I’ll have to spring for a proper gauge and pump. The pump I have is too powerful and the gauge is in the wrong range. But I’ll be replacing the damper tomorrow or next. Thanks for the input.

 

[pjtoledo]

ok, on Flex Fuel 3.0 the pressure regulator is in the fuel filter. the filter has 2 ports facing the rear and only 1 going towards the engine ,,right???
can you elaborate on the too powerful pump & wrong gauge? your vacuum pump is too powerful??
if the fuel pressure at the rail is in spec then the pump & regulator/filter are OK.
the nominal fuel pressure is about 47-63 according to Chiltons.
it can vary a bit, the computer constantly adjusts injector timing after reading the O2 sensors and other stuff.

just in case, hope it doesn't apply to you.
the flex module that measures the alcohol content has a failure mode where it tells the computer to dump a lot of fuel into the engine.
throws a code saying its output is out of range.

 

[Jeide]

can you elaborate on the too powerful pump & wrong gauge? your vacuum pump is too powerful??

I have an electric vacuum pump that I used to get the moisture out of the A/C lines before I charged the A/C system. I tried using that and it pegged the gauge that I had attached to it. The gauge didn’t measure psi but inches of mercury. I have since converted it to psi and the pump was actually ok to use but not the gauge.
anyway, I replaced the damper and at first I didn’t think it worked but after burning off the residual fuel in the intake it’s running just fine. Thanks for the help.