Gas Leak Lower Intake Manifold

[tommyb]

Went to put the 84 SVO away for the winter this afternoon, it took a little cranking since it hadn't been started since April but was finally idling nicely in the driveway. After warming up I decided to take a little spin and when I arrived home there was a puddle in the driveway and a trail up the street from when I took off, CRAP! Well I put my finger in it and it sure was gasoline. The lower intake was pooled with gas in the recessed cavities. It was not the gas line so I guess it has to be an injector or maybe multiple injectors. Is it most likely that a seal went? On the top or the bottom? Is the best way to answer this to start the car and simply observe where the gas is coming from? The manifold was replaced 1 or 2 years ago with a square intake which was a little crusty. If this is the culprit what is the best way to clean up these sealing surfaces. Depending on what is wrong is it a good idea while everything is apart just to replace all of the injectors? Thanks for any thoughts you can share.

Tom

[MikeFleming]

First. know where the fire bottles are. Put them in your exit path - so you run away from the fire towards a safe area, should there be one, to get to the bottles.

Then clean up the mess as best you can.

If it's leaking, there are only a few places it can leak from:

- The body of an injector(s) - between the plastic body and the metal top. Replace is the only solution.
- Between the top body and fuel rail at the top o-ring (will not leak fuel at the bottom o-ring seal.
- The FPR body (top/bottom crimp) and/or seals to the fuel rail or the diaphragm ruptured and it's leaking out the top to the vac/pressure hose (but then it wouldn't drive very well).

If I were to hazard a guess, I'd say it's an injector body if they're original unit.

You only need to energize the fuel pump to see the leak if it's big enough - no need to run the engine. Ignition key On, Off, On. will be enough to pressurize the rail.
That's about it.

[tommyb]

Mike,

Thanks for the reply, just a follow-up, why can't it leak at the bottom o-ring in the lower manifold? I will try to find a helper to look for the leak or turn the key energizing the fuel pump.

Tom

[MikeFleming]

why can't it leak at the bottom o-ring in the lower manifold? Yep - the seals can leak there - but there's no pressurized fuel at the bottom of the injectors.

Leaks at the bottom o-ring show up as intake manifold air leaks - leaning on part throttle/vacuum; richening under boost/[air] pressure.

[Raven855]

We had this happen at Sturgis this year. A guy from Joplin had a couple of injectors that started leaking at the injector body. Dave just happened to have a set of balanced and matched injectors he sold to the guy and we put them in at the rental house. He ended up being very happy with the experience. His performance improved and his fuel economy went up.

[tommyb]

Thanks for the advice, this will be my first Spring project!!

[JTurbo]

I had leaky injector o-ring on my 86 SVO (of course it was #1 injector right by the alternator / distributor). Bought an o-ring kit from Napa and all is well...

[tommyb]

I hope I can get by that cheap! Haven't had the time to check out the exact culprit yet.

[MSheff]

Yep, the guy at Sturgis was REALLY happy! That guy was me. We thought o-rings at first, which we replaced only to find we still had a leak. Once we looked close you could see the fuel coming right out of the side of the injectors, two of them.