Help w/ m20 fuel leak

[GThomas]

Hey guys,

Need some help with diagnosing this fuel leak. I can only work on the car over the weekend as its far away from my apartment. So I'm trying to get all the info and parts before hand so I can go in with some things to look for.

Backstory -Older vert that i'm making road worthy again. Started it after a month of sitting. Battery would barely turn over but started after a jump. Smelled fuel and took a quick vid before turning her off. Seems to be leaking from under the throttle body. Are there common failure points? More likely to be a hose or fuel rail? Any ideas would help. Also is this something that would most likely involve removing the intake manifold to get to? New to the m20 so appreciate the help.

excuse the poor vid -

[badwella]

You shouldn't have to remove the intake.

There's an evap system that connects to the bottom of your throttle body. It's the fuel vapor recovery system It has a purge solenoid/valve on it and pulls the vapors from your gas tank into the intake to burn, etc. If that has fallen off (which happens a lot since the rubber is old) then it'll make it smell like a fuel leak.

That hose you see here: The arrow is where your charcoal canister connects



See this photo of the m20 throttle body:



The small brass nipple on the bottom is where that purge valve connects. You can use a section of 5/16" low pressure fuel hose to connect the valve to this nipple. I recommend hose clamps as well.

I do recommend replacing the fuel hoses. They deteriorate over time and fall apart. You need probably at least 7 feet of fuel injection hose 5/16" OD IIRC (make sure it's fuel injection hose and not regular fuel line hose as it will burst from the fuel pressure). Replace them one at a time so you don't forget where they connect to. One is the high pressure side and one is the return/low pressure side of your fuel rail.

Feel free to PM me if you have questions. If this isn't the problem, you could also have a leaking o-ring on your injector. That would require removing the intake so try this fix first.

[dnguyen1963]

If your car still has the original fuel hoses then they probably contain a million cracks in them. Replace them all before driving the car again.

[MrBurgundy]

Is are you seeing the gas drip by the throttle body, or are you just smelling it. If you're just smelling it, it's probably the hose mention above.

[Kershaw]

That looks like injector o-ring(s) leaking. Pull the fuel rail, put new o-rings, reinstall. Parts stores might not have "e30" o-rings, but just get 1992 Ford Mustang V8 o-rings.