Force4

Hello all,

I just recently installed an air/fuel ratio gauge in my stang. I am averaging a 12.0-13.0 at idle to 3000rpm but when I go wide open I see her go all way down to 10.9 and seems to average around there until I let off. Its an Inovative LC-2 I believe so I know its fairly accurate. I have no vacuum leaks and my Timing as at 10 degrees I believe (Hard to tell because paint wore off of balancer). Is my issue jetting or could something else be at play?

Holley 770 Street Avenger

j-town_edge

At a 10.9 at WOT? Wow. If the gauge is brand new and you know it's not an issue with the gauge, I would have to think it's the jetting. You might be able to try some "trial and error" with the jetting to see if that makes changes.

I might be wrong on this, but isn't there a noticeable difference in the exhaust smell if you are running that rich compared to more "normal" A/F ratio?

Notice any blue tint to the exhaust at all when at WOT?

Force4

When I initally installed the motor two years ago she seemed to puff a bit of smoke after letting off from WOT. Like I said at Idle and rev up she seems steady in the 12.0-12.5 range (Which is still a tad low) but at wide open she drops. It doesnt smell rich when running idle, maby a tad, no backfires or pops etc. Im going to check the spark splugs hopefully this week, id assume they should black from being rich.

Force4

I have a video of first-third gear with A/F. Ill try to post it in a bit.

Force4

http://s59.photobucket.com/user/Forc...261da.mp4.html

Flashplayer doesnt work for me so I cant tell if this link actually works, just let me know.

uedlose

pull some jet out of it and try it again. I would drop 2 sizes and go from there

Force4

Ok my Primary right now is a 70mm and my Secondary is a 65mm, go down to say a 60mm and a 65mm?

Force4

Im almost getting the impression my carb in general is to large, from what i am reading a mild 393 build like mine only needs a 670cfm appose to a 770? hrmm

uedlose

there is nothing wrong with the size of the carb on that many CID. try the jet change and the run it again and see what your numbers are. You may have to do this a few times till you get it where you want tuning dont happen in mins. very often.
Despite what you hear a carb to large would be lean not rich. do to not getting enough vac and velocity through the carb. Learned the from reading a big right up by a guy they called the Fuel doctor I think it was. He taught EFI tuning.