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S Chassis Technical discussion related to the S Chassis such as the S12, S13, S14, and S15.


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Old 07-24-2015, 02:09 PM   #1
Jorge18
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I have a stupid question re: injectors

I'm having some issues with my car running very rich and my pistons flooding with fuel. I've read on here repeatedly that it could be that one of my injector O ring could be bad.

Maybe I'm being stupid, but I can't figure out how a bad o ring would cause the car to run as rich as it's running (10 AFR)

Can anyone explain this to me?
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Old 07-24-2015, 04:25 PM   #2
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the Oring is a gasket in essence. If it's ripped or missing it will leak fuel right into the Intake.
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Old 07-24-2015, 11:09 PM   #3
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Not sure about the o ring thing. Unless its inside the injector. Injector not sealing is gonna be a lean situation as in vac leak or fuel spewing out of fuel rail. Sounds like you have a wideband which helps. Is it always pegged on 10? I had RC knockoffs that were way off on resistance and had the same problem. They were too open for too long. What mods are you using ( engine wise )?

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Old 07-25-2015, 09:04 AM   #4
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Fuel leaks past the lower O-ring and around the injector body directly into the cylinder rather than being metered thru the injector. It doesn't leak externally.

External leaks are usually from bent fuel rail, bad manifold spacers, wrong or incorrectly seated upper O-rings.
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Old 07-25-2015, 01:37 PM   #5
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The injector only gets a certain amount of fuel. Either it goes through injector at the correct rate when it pulses or it does not. Fuel not going through the injector and you have a missfire and possibly a real fire if its a bad leak. We are talking about top feed injectors right. Fuel going past an oring isnt going in your engine, its going there when the oring is not leaking. Without knowing mods check your resistance on injectors. No disrespect on the oring thing, if thats what it is you'll save a ton of money.
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Old 07-25-2015, 03:13 PM   #6
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Quote:
Originally Posted by kane01 View Post
We are talking about top feed injectors right.
Although OP didn't specify, stock SR and KA injectors are side-feed. On side-feed when the lower O-ring is leaking the fuel goes straight into the engine.

You are right with top feed - you see the leak externally.
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Old 07-25-2015, 03:34 PM   #7
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There is an s on on the end of the word piston in his comment. That screams wrong injectors. Do all of the stock ORINGS go bad at the same time, why does anyone use them at all then. Anyway, good luck with your issue. If you changed anything lately prior to the problem(like all your injectors) i would start with checking resistance, need to know how old injectors are functioning anyway.
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Old 07-25-2015, 01:54 PM   #8
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pull the rail out and run the pump. Leaks will become obvious.
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Old 07-25-2015, 03:13 PM   #9
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Quote:
Originally Posted by Omega View Post
btw pics?
damage? cracks? warping? chips? etc
You tried to redeem yourself but....:thumbdown:
Any fuel leaking externally from a top feed injector should be obvious.

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