What causes car to run rich?

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Nov 16, 2007 | 06:07 PM

Scrapin'4.8

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From: Liberty SC

What causes car to run rich?

Just like the title says. What all will cause an LT1 to run rich. My car runs EXTREMELY RICH, so rich that i'm pretty sure it's fouled out most the plugs causing it to have a horrible miss during hard acceleration. I know about exhaust leaks before the o2's, checking the regulator to see if it's bad, the ECT sensor, and sometimes bad tuning. I don't think my car has any of them problems though, reason being, before i even crank the engine up, if i press the shrader valve, it shoots a good amount of fuel out. Now i know it's supposed to spray fuel anyway, as i've did it many times before. So maybe a clogged up return line? Is there anything in the return line from where it connects at the FPR to where it connects above the fuel filter? I'm gonna take it off tomorrow and spray some air through it and hope like hell something comes flying out. But is there anything else that will cause these problems?? Thanx a lot!

Nov 16, 2007 | 06:22 PM

jasonp31

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From: Clover, South Carolina

o2 sensors, junk fuel, MAF sensor, air filter, that's a few things off of the top of my head.

Nov 16, 2007 | 06:37 PM

Camaro_freak

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From: Algonquin, IL

Maybe cat overtemp protection. I battled this for over a year before I figured it out. It wasn't horribly rich, but definitely richer than it was supposed to be.

Nov 16, 2007 | 08:14 PM

infinitebird

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Could be bad o2s, no real way to diagnose that without a scanner.

Nov 16, 2007 | 08:48 PM

TXFORMULA

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you could always replace the o2's anyway to see.

and camaro freak , what is cat overtemp protection?

Nov 16, 2007 | 08:57 PM

jasonp31

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From: Clover, South Carolina

I know you didn't ask me, but cat overtemp protection is basically this. The cat temperature is monitored by the computer, and if it rises above a preset number, then the PCM will adjust the fuel to attempt to lower that temperature and protect the cat from melting down.

Nov 17, 2007 | 02:57 PM

Scrapin'4.8

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From: Liberty SC

I've replaced the o2's already, actually replaced them before it started running rich. Will any sensors cause it to have that much fuel come out of the shrader valve??