anyone know anything about having a slightly reground cam being able to cause a rich code by having enough overlap to let some un-burnt fuel get thru to the front o2 sensor, causing it to read a rich state?

Yes, the cams create a lower vacuum at idle due to the overlap of the cams. This can peg the Long Term Fuel Trim and give you the code. Plug a datalogger in and I'll bet you see the fuel trim all messed up. Time to play wwith the S-AFC.



15.9 @ 86.7mph

Smooth idle? We don't need no stinking smooth idle.

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my datalogger does have my LTFT pegged around 25, with an average of 21 to 22, so...
but it has always read that high even before my dyno run with wide-band O2 readings that had me running dangerously lean. So even thou in acuality i was running lean, my car was thowing a rich code.
ideas...?

What injectors are you using?

If fuel trim is pegged and the ECU can't adjust any more you will get a code. If you are not getting enough fuel sounds like your injectors aren't big enough, or your fuel curve and low throttle tuning are out of wack and you get a rich code in your low throttle situations and then you are almost running out of fuel at WOT. Sound mainly like a tuning issue to me.

*edit* pegged +25% or -25% at throttle ranges for low throttle do you max out your fuel trim? I highly doubt the rich code is being produced at WOT, but... What does your AF gauge read, especially in relation to the wideband O2. I have the feeling it's a low throttle code. What size injectors are you running? go through your set up again?



15.9 @ 86.7mph

Smooth idle? We don't need no stinking smooth idle.

Mods List:
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What injectors are you using?

If fuel trim is pegged and the ECU can't adjust any more you will get a code. If you are not getting enough fuel sounds like your injectors aren't big enough, or your fuel curve and low throttle tuning are out of wack and you get a rich code in your low throttle situations and then you are almost running out of fuel at WOT. Sound mainly like a tuning issue to me.

*edit* pegged +25% or -25% at throttle ranges for low throttle do you max out your fuel trim? I highly doubt the rich code is being produced at WOT, but... What does your AF gauge read, especially in relation to the wideband O2. I have the feeling it's a low throttle code. What size injectors are you running? go through your set up again?
******************************************************************

Im using accell 30lbs, slight regrind on stock cams, Wlabro 255, SFMU with idle of 34lbs, 8 psi max boost.
My LTFT's are -25% with an average of -22 to -24%. These are closed loop #'s looking back on multiple pre-dyno runs from my Alex Peper datalogger.

the weird part is that for a long time i was thinking i was running rich because of the rich code, my digital jumptronix A/F gauge said i was rich, and my datalogger said i was rich. I even had my fuel pressure down to 16-18psi and was still showing rich.
the dyno guys used a wide-band o2 sensor and i was in actuality running way to lean. They were suprised i still had a working motor.
They got me 14 more HP just from uping the fuel and adjusting the SAFC.
My A/F still says im running rich with WOT #'s of 1.03-1.07v.

This is why i posted this about the regrinds. The dyno guys said that its very possible that they could be the cause on my rich readings even when i was lean. so then the next question is with my AEM am gears could i maybe take out the overlap by adjusting them some? I hovae then at 0 now.

Is it possible that i could have somehow wiered my A/F gauge into the downstream O2 sensor?

>Im using accell 30lbs, slight regrind on stock cams, Wlabro
>255, SFMU with idle of 34lbs, 8 psi max boost.
>My LTFT's are -25% with an average of -22 to -24%. These are
>closed loop #'s looking back on multiple pre-dyno runs from my
>Alex Peper datalogger.

That's exactly what is causing the rich code. fuel trimmed pegged neg 25% means it can lean any more and you are going to get your rich code.

>the weird part is that for a long time i was thinking i was
>running rich because of the rich code, my digital jumptronix
>A/F gauge said i was rich, and my datalogger said i was rich.
>I even had my fuel pressure down to 16-18psi and was still
>showing rich.
>the dyno guys used a wide-band o2 sensor and i was in
>actuality running way to lean. They were suprised i still had
>a working motor.
>They got me 14 more HP just from uping the fuel and adjusting
>the SAFC.
>My A/F still says im running rich with WOT #'s of 1.03-1.07v.

Tune the S-AFC at low throttle situations, The 30lbs need to be leaned out I'm down in the range of -25% adjustment at idle with stock injectors, the 30lbs are going to need to be trimmed down a bit.

>This is why i posted this about the regrinds. The dyno guys
>said that its very possible that they could be the cause on my
>rich readings even when i was lean. so then the next question
>is with my AEM am gears could i maybe take out the overlap by
>adjusting them some? I hovae then at 0 now.
>
>Is it possible that i could have somehow wiered my A/F gauge
>into the downstream O2 sensor?

It is possible the wiring on youe AF isn't solid, I would check, to make sure you have a good ground and power sounds and then that you tapped te right wire at the ECU. You really shouldn't be getting a reading over 1v. You may have a weak, low ampherage power source on your gauge. Also make sure it's a solid ground. Then check the calibration on the gauge, get a good multimeter and see that the gauge output matches the m,ultimeter... wait you said you have a datalogger: check the ECU's numbers vs. your gauge.

Yes you can get get some unburned fuel pulled through due to overlap, but I think your problem lies in low throttle tuning and your gauge.



15.9 @ 86.7mph

Smooth idle? We don't need no stinking smooth idle.

Mods List:
http://highlander.dsmpower.com/sig.htm