SES light
Thread Starter
Launching!
Joined: Nov 2001
Posts: 225
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From: Ft. Worth, TX
SES light I have heard different answers from different people. I put mac headers w/ ORY pipe (no cats) and a cam on my car; Autotap says SES light is on because of no cats and random misfire. Does this hurt hp at all? Has anyone done back to back tests? Like using Atap to reset SES on the second run?
Re: SES light I would think YES it would hurt hp. A misfire doesn't help anything. The O2's sending info to the PCM saying something like: "hey you running too rich" or "hey you have bad cats" would mess up the A/F mixture and timing, etc. O2 sims will solve this though, may stop misfire too? Well, that's my theory anyway.
TECH Resident
Joined: Dec 2001
Posts: 922
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From: Lexington Park, MD
Re: SES light [quote]Originally posted by Kdubroc 99 SS:
<strong>I would think YES it would hurt hp. A misfire doesn't help anything. The O2's sending info to the PCM saying something like: "hey you running too rich" or "hey you have bad cats" would mess up the A/F mixture and timing, etc. O2 sims will solve this though, may stop misfire too? Well, that's my theory anyway.</strong><hr></blockquote>
No, post-cat O2's have no impact on A/F. They are there to to verify cat operation.
<strong>I would think YES it would hurt hp. A misfire doesn't help anything. The O2's sending info to the PCM saying something like: "hey you running too rich" or "hey you have bad cats" would mess up the A/F mixture and timing, etc. O2 sims will solve this though, may stop misfire too? Well, that's my theory anyway.</strong><hr></blockquote>
No, post-cat O2's have no impact on A/F. They are there to to verify cat operation.
TECH Enthusiast
Joined: Nov 2001
Posts: 521
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From: Farmingdale NJ
Re: SES light Well, the no cats issue can be cleared up with some O2 sims. As for the random misfire, make sure you don't have anything banging on the exhaust, it could be sending noise pulses back up the exhaust and triggering the knock sensors. That would explain it's randomness. It's not uncommon for Y-pipes to bang of the chassis a little. Try resetting your PCM also, and see what codes come back.
The no cats code will not hurt HP, but the random misfire will probably give you some knock retard and mabey richen up the fuel a smidge also. That will drop your horsepower.
Pete
The no cats code will not hurt HP, but the random misfire will probably give you some knock retard and mabey richen up the fuel a smidge also. That will drop your horsepower.
Pete