I have a VERY small vacume leak in my #8 Fuel Injector bore. I put a new o ring on the new injector with it and placed it in my new Edelbock intake, but when i spray a little carb cleaner at that injector I can just hear the engine stumble just a tad. I have tighted the fuel rails down even more adn its very very very small leak now. but can i place a littel RTV around the injector down in the bore? Thanks
350 TPI

 

my guess is you cut the o ring when you put it in. i'd replace the o ring, look for anything that might cause a leak, like part of an old o ring.

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ICON Motorsports

1st & 3rd

 

Yes, something like Ultra-Copper Silicone RTV will do fine.
Make sure the area is very clean (alcohol works great to remove fuel & grease)

Just use enough RTV that the fuel will not disolve it away quickly. Should last a very long time.

good luck
ODB

 

There are non-hardening sealants that dont break down when exposed to gasoline, unlike silicone, so why use anything else?
I'd replace the oring and check the injector bore for burrs or similar.

 

You're right madmax,
I had just assumed that he already tried another O-ring and inspected the bore.
I just picked the silicone because most of us normally have it lying around.

 

Hmmn, if you've a vacuum leak at the injector, and you spray carb cleaner at it, the idle should increase fairly smoothly...not stumble...I wonder if the carb cleaner is affecting the injector somehow?

 

Tried the new o ring. When idleling at about 500 i sprayed between the injector and the bore like 1/8wide with the stick form the cleaner and it stumbeled so I am wondering if its something else.

 

spray will not affect a fuel injector. It is a vacuum leak.

carb cleaner does not always raise your idle speed when it enters your induction.

ODB

 

Yeah, it doesn't always raise the RPM. If you spay fuel in the cylender, and there isn't air to go with it, it will richen to much and it will stumble. Are you using injector O-rings?

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That's right. I remember seeing O-rings out there with the correct I.D. but much thicker. I had to use the fattys on my Acell intake years ago to get my Ford injectors to seal.
good call.

ODB

 

The o rings came with the injectors. I have the MSD ones.