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xfi tuning help

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Old Oct 9, 2008 | 02:59 AM
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ive been running an xfi on my 89 rs ls1. its a stock motor still, but have plans to change that in the future. i tuned it myself and got it to run good. been driving it for a couple years now. recently i went to look in it and saw afr is getting down to 10 or 9 when i get on it. i think i even saw an 8 once. might explain the shitty gas mileage. but if i go to any of the ae tables and lean them out, it would stumble and backfire off the line. and it seemed like it was still going rich. why is it so far off the target afr and what can i do to make it run leaner but not stumble and backfire. i was thinking it might need to go rich for a second, but increase the rate of ae decay? the car only went 13.35 at 106 2 years ago and it weighs 3250. with the mph it seems like it should be in the 12s, and if it wasnt so rich it should make more power. if anyone has any ideas or wants to look at any of the tune file, let me know. thanks
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Old Oct 9, 2008 | 04:32 PM
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Zex kit leaking fuel into the engine?
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Old Oct 9, 2008 | 05:36 PM
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i wish it was that simple
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Old Oct 9, 2008 | 07:38 PM
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Are you running closed loop at w.o.t? If so sounds like your o2 took a dump.
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Old Oct 9, 2008 | 09:34 PM
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yes, its in closed loop. what do i have to do to check the o2 sensor? the o2 corrrection does help, its just the correction limits arent set high enough to correct for this problem. i could increase the correction limits, but that would just be a bandaid, i want to track down what is causing the problem, not just find a way to minimize it. i think the o2 should be good, otherwise would it not give a good afr reading ( which seems to be fine and accurate the rest of the time)? its fine when in light throttle and cruising, but when the pedal goes down it goes rich. i could maybe zero the ae vs tps position table, maybe it gets enough ae from the tps rate of change and map rate of change tables, and increase the ae rate of decay. ill try to mess with it tomorrow, but i usually end up going back to the original tune cause it starts acting up when ive tried to mess with these tables.
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