is it possible

[svtsilversnake]

yester day friday the 26th my check enginelight came on and it does every now and then and im almost positive that its my filler neck gasket is cracked and it leaks a fuel and its settin off my emmisions sensor back there....well anyway if you read my post about what i pulled today then is it possible that when i pulled my batt cables to clear my check code could that be y i ran so rich and only make 284hp because the curve is smooth smooth but from 2000rpm its like 75hp and climbs shouldnt it start out alot higer...atleast everyone eleses was like that. my a/f ratio was12.0 flat all the way to 5300rpm then it droped to 10.4....suuuuuuuuuper rich.....could this be the factory baseline before it were to relearn the curve.....just wounderin......or du i just need a tune cuz thats what the guy at the shop said but i didnt even think about disconectin my batt yesterday or id have asked him if that could be it????????????????????heeelllllllppppppppp?



well atleast i wont break anything runnin that rich...lol

[lafinrat]

The WOT maps are not learned. They are all pre-programmed. Only idle through part throttle is learned and adjusted (closed loop). I have yet to see a wide band from the factory. I've heard some really new cars have them, like 2007 and up, but I don't know which ones.

10.4:1 AF should blow black smoke. You seen any of that on the dyno? If not, the O2 on the dyno may be wrong. Otherwise you have an issue that needs resolved for max power and longevity.

[svtsilversnake]

yea it blew smoke...but a richer mixture yealds less power but is better on your parts
.ritht

[lafinrat]

Originally Posted by svtsilversnake

yea it blew smoke...but a richer mixture yealds less power but is better on your parts
.ritht

Kinda. A slightly rich mixture will keep combustion temps down and keep things safe. An overly rich mixture will carbon up the motor, exhaust and O2 sensors. And, it will overheat the cats, if equipped. Cats work by burning excess HC (hydrocarbons or fuel). If there is too much HC in the exhaust stream, catalyst temps will soar and eventually the catalyst will fail. If you are still utilizing the TWC (three way catalytic) system, you'll end up with catalyst effeciency codes.

Also, the piston rings may become carboned. This build up cannot be completely alleviated without tearing down the motor and re-ringing it. If the mixture is rich for too long, ring seal will be degraded to a point that the oil film will be washed fromt he cylinders and the cylinders will become glazed. Correcting this would require honing or reboring.

11.5-12.0:1 AF is a safe rich limit for a NA motor. Past that is just too rich.

If you are truely at 10.4:1, something is wrong. Too much fuel pressure, too big injectors, dirty/malfunctioning MAF, etc.

A dirty MAF may cause a lean mixture down low and rich up high.

[hotwheels]

I would have to go with a dirty MAF too.......the computer should keep your car within a good fuel band.....

[lafinrat]

I forgot to add, you'll see a good peak HP and torque compromise at about 12.5:1 with most NA motors. Peak HP is usually about 12.2:1 and torque about 12.8:1, if memory serves me, which it seldom does.

[svtsilversnake]

yea it goes rich to 10.4 past 5k and is flat 12 from 2k to 5k.and i dont think its a dirty mass air i cleaned it like 2 months ago but ill check it again

[einehund]

sorry to jack this, but how do you clean that. i put on a BBK CAI and ever since (i think i put too much oil on the filter) my car has been idling funny, like surging and dropping too low. i didn't have any problems before the switch and my fuel filter is new (i changed that a month before the CAI)

[Intmdtr]

Originally Posted by einehund

sorry to jack this, but how do you clean that. i put on a BBK CAI and ever since (i think i put too much oil on the filter) my car has been idling funny, like surging and dropping too low. i didn't have any problems before the switch and my fuel filter is new (i changed that a month before the CAI)

didn't crack a wire on your MAF when you put it back together did ya?

[einehund]

no, i checked that. and the connectors are all clean on the plug.