Vannin' Home Forums Chevy General Discussion Leaky TBI / arcing sparks... (G20)

When I was tightening the air filter down onto the throttle body today I noticed the thin gasket under the TBI cover (that encircled it) was really wet and bubbling out gasoline along that edge as it was getting squeezed down. upon closer inspection (TBI cover off) there is a good amount of slickness all over the TBI. I don't remember it being like this. How wet should it be inside there?

It's probably something i wouldn't have taken too much notice of but I found a spark jumping from one of the spark plug wires today while working on something unrelated. I fixed that grounding issue and there's no more random electrical arcs.

But gas leaking from under the TBI cover near arcing jolts of raw electricity doesn't seem like the best thing to have going on.

Thoughts?

So when you say TBI "cover"...which part are you speaking of?

it's not in that picture. I'm a noob and learning as I go so I'm sure the terminology isn't right / the metal, cover, protector, etc... that encircles the TBI. the air filter sits atop of it.

Hi Rickyralph,

Welcome to the site.

Excellent Illustration Dyno_Dave.

Sounds like the Air cleaner assembly. ? The nut securing it should be snugged down firm, not overly tight.

There is fuel present inside, sprayed from the injectors.
There should be no fuel present on the outside of the throttle body.
Even with the engine running for diagnostic work, with doghouse and air cleaner off.

Fuel injection systems operate under increased pressure, and require special hose and clamps. Check all of your fuel lines for leaks.

If you have any arcing caused by old plug wires, they should be replaced.

OK, I know the pickups use an extra ring or spacer between the TBI unit itself, and the air cleaner. Perhaps vans did too, I don't know. But if you have raw fuel leaking past the joint between the TBI and spacer, or the spacer and air cleaner, I would think there's still an issue with the TBI or lines. Those injectors should spray in a nice even cone pattern right straight down into the the bores of the throttle body. None should be going sideways and hitting that metal ring or spacer. If it is, there's a problem.

There are seals on the TBI unit for the injectors and pressure regulator. Kits to reseal them are cheap.
EBAY KIT

A quick study of some of the kits and whatnot on ebay will also give you an idea of how they come apart.

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