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Help!!!!!! (air/fuel ratio)

  • Thread starter Thread starter jasonh_86
  • Start date Start date Jan 3, 2006
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Mike97gt

it doe snot
Founding Member
Jan 26, 1999
10,633
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89
the people's republic of massachusetts
Jan 4, 2006
#21
  • Jan 4, 2006
  • #21
there must have been somthing wrong with the datalogging, wideband setup.. at 18-1 you would be pinging like crazy esp with your timming adjuster at 16...
 

BooWFO

New Member
May 10, 2005
991
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0
Louisville, KY
Jan 4, 2006
#22
  • Jan 4, 2006
  • #22
Is it just me or does it seem like there is alot of "my AF was way lean" Cai cars?
Anyways. Also are you sure your exhaust is good and tight? Awhile back on my way home from Bowling Green (100+miles) I hit a deer body in the middle of the road it pulled my prochamber down and away from the manifold a little after which I started getting lean codes on that bank. Just something else to think about.
 

DBMSTNG

I fantasize about it being BIG!
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Jan 4, 2006
#23
  • Jan 4, 2006
  • #23
hotmustang331 said:
Funny thing, after I installed my cams we drove to GA for Tims tune. there Tim told me my cars idle A/F was @ 18-1...no CEL either . He didnt say the A/F, but I do know he shut it down mid run and then started tuning...so apparently it went way too lean. It was 14-15 before the cams, so I couldnt imagine. I would think a WOT A/F of 18-1 would melt the pistons, and he would no doubt hava ALOT of knock @ 16*s. Im also thinking that the A/F tool was jacked to an extent.
Click to expand...


did Tim give you a base tune to drive the car with until he tuned it? if so i wonder if the adaptive learning was turned off and if that prevents the CEL. with the adaptive learning on, the car would try to bring itself down to 14.7:1. if it couldn't do it, i'd assume it would then throw a code.
 

jasonh_86

I
May 20, 2005
1,156
2
48
Arkansas
Jan 4, 2006
#24
  • Jan 4, 2006
  • #24
It's never thrown a code, but I know that the dyno's datalogger/wideband wasn't off. He said he's only seen about 10 cars come in that lean but that it happens.

I saw graphs and a/f's of other cars and they were all normal and he used the same equipment the same way. He's been there for a few years, so it's not like he's new to the whole dyno thing.

He reset his stuff and repositioned it and it still read the same, so I would believe that my car is really running that lean.

After I backed my timing down, I could smell more of a gas-like scent coming from my car while it's sitting there idling. I may change a couple more things and make sure all of my exhaust is tightened and not leaking anywhere, then take it back and see what it'll do after a couple adjustments.

Anymore suggestions are appreciated tho. :SNSign:
 

jstreet0204

Active Member
Jun 26, 2003
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Winston Salem, NC
Jan 4, 2006
#25
  • Jan 4, 2006
  • #25
Check your plugs that will tell you if it is really that lean.
http://www.dansmc.com/Spark_Plugs/Spark_Plugs_catalog.html
 

hotmustang331

Active Member
Apr 29, 2004
2,967
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48
Bastrop,TX
Jan 4, 2006
#26
  • Jan 4, 2006
  • #26
DBMSTNG said:
did Tim give you a base tune to drive the car with until he tuned it? if so i wonder if the adaptive learning was turned off and if that prevents the CEL. with the adaptive learning on, the car would try to bring itself down to 14.7:1. if it couldn't do it, i'd assume it would then throw a code.
Click to expand...

Nope, it was a tune I got from mustangtuning(mail..sucked in teh A/F area, but made the car run alot better)...way before I was even thinking about cams. It was running 14-15 A/F BEFORE cams, JLT RAI, and 75MM TB, so it probably went outside of its adjustment limits. I drove it like that for about a week before I drove to GA. (no WOT blasts lol, just took it easy for the most part..got close to/maybe at WOT once though but just for a split sec) . Its funny because he actually laughed that it was running that lean at idle..guess he doesnt see that much lol.
 
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