Hi all,
I was wondering what the most likely cause of excessive fuel coming out of intake trumpets might be. I have a 4.2 with triple Webers. By excessive I mean entire bottom of cold air box covered in fuel and me smelling like I swam in a fuel tank from shoe to hair every time I drive the car. My garage wrecks of fumes constantly. I’ve heard that a little fuel coming out especially after spirited driving might be normal, but this is more than a little IMHO and it didn’t used to do this, so something has changed. Anyone run into this before?
Now that you mentioned it…
The very first place I would check, of course, is the fuel level of the floats: if they’re within spec, then it’s probably a function of Reid vapor pressure and that’s a hard problem to fix.
You might also take a look at the inlet needles, if Viton, they’re probably petrified, and won’t resist the boiling pressure of the gasoline in the lines as it sits after running.
If metal on metal, then they may be worn out.
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Think I found it. Loose banjo nut on front Weber created a perfect tiny stream of gas pointed right at the bonnet louvers on the driver’s side. I also lowered the fuel pressure to 2.75 psi, was set at a little over 3 psi.
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No big problem in lowering the fuel pressure, but Webers do fine at around four PSI.
Interesting. I have very little experience with Webers. I only lowered it because I was told by other Jag guys to keep it just under 3 psi.