Fuel Problem????
 

I have 680's and 720's (turned out Enzo250 sold me 680 but had said they were 720cc and posted them for sale as 720's) But I added 720 and moved the 680's, And I still cant move my fuel curve. It runs really rich on the street and boggs from so much fuel. My a/f ratio moved 1 point and I can't lean it out or richen it. I even turned down the boost and no change. Last run I turned the boost way down to 9psi and it went from 12 to 15 on the a/f with black smoke out the tailpipe. Something is wrong. The a/f ratios should move if i turn the boost down from 12 to 9 right? Or if i take away 10%. Nothing. Dunno what to do. Cant imagine I need more fuel. Any help would be great! Thanx! From the looks of it if I need more fuel I would need a lot, I added 340cc (13%) and it barley moved, Not even a whole point. I would need like 1000cc injectors. But even with the boost lower and less power like 257rwhp at 7psi same curve on the o2 sensor. ?? Should the wideband jump when a puff of black smoke comes out the pipe? The graph didnt move???

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first of all what are you using to measure the air / fuel?

" I turned the boost way down to 9psi and it went from 12 to 15 on the a/f with black smoke out the tailpipe"

15:1 A/F is lean as hell and would blow your engine. it wouldn't be spiting out fuel.

it should be around 12:1 or a bit lower.

the lower the number the richer it is.

changing the boost shouldn't effect a/f ration much at all. lower boost the ecu sees xx% less air going it so it just puts xx% less fuel in.

with any a/f gauge, with a warmed up car and o2 sensor (driven a bit) you should see big changes when you move the S-afc up and down (at that rpm point...) test it at idle.

if nothing happens I would suspect the afc or wiring.

what fuel pump are you using?

Walbro pump, rewired. Im using the Wideband from the dyno shop.

How do I test it at idle. The car runs rich on the street and Im able to turn it down and stop it from bogging on the street. But I dunno what else to do.

do you understand how to use the S-afc? what the hi and low levels are? what are they set at?

is it hooked up to the TPS like it should be? or are you using the boost sensor instead?

"how do I test it at idle"

idle the car with the wide band in. on the low setting on the S-AFC turn the 1000rpm range up and down and see if the readings on the wide band change to confirm the S-afc is doing anything.

I know how to use it. The Hi was zeroed out. Then I tryed adding 5% and nothing happen. Same fuel curve overlapping the other one. Then to test it we took out -10 then 15 then 30%. and nothing happened. then back to 0 same curve. all runs over lapping.

I can change it at idle. It lowers and raises it.

hooked up to the tps.

Who made the wideband?? Make or brand is what I'm referring to. Thank you.

and does it happen to be after a cat?

I dont have cats.

But you do SEEM to have a wideband problem.

You better get on a dyno and a real wideband before you blow up anything playing with the AFC. Going down -30 is very dangerous. My AFC is clicked up 2% after 4000 rpm with 720 secondaries when I had stock turbo. If playing with the AFC does nothing, re-check the wiring again. At idle, just one click up or down affects the A/F gauge.

well i have 680cc primaries. SO tuned down -30% it still;l rich on the dyno guys o2 wideband. about 12.9-13.1 If its up any higher it idles rough and really smells. So my afc is working. I suppose at 295rwhp I still don't have enough fuel. so turnning it up does nothing.