BANSHEE

1987 mustang with a vortech supercharger 10# boost, seems to be lean on deacceleration, then computer seems to richen it up to much?? smell gas & alot of black smoke any ideas??also has 73mm c&l

sastangman

do you have a aftermarket ignition system?like msd 6al or crane?

BANSHEE

yes i have a msd 6al, plus iit only started doing it after i had it on the chassis dyno??

99saleen351r

sounds like you got a bad tune.....whats your A/F ratio??If its at or around 11.5 throu out the power band its fine.Why would it matter on deceleration anyways your not pressing the gas so of course it will be lean at high rpms with no gas

BANSHEE

im new, what do mean by bad tune, or what to tune?? smells & looks bad (black smoke) when you pull away after deaccelerating

wildstang87

get a dyno a/f ratio tune, if youre puffin black smoke youre running rich/burning too much gas.

sly_1969

buy a new ecu from AEM.

86HOGT

The car's supposed to go lean under decelleration, other wise it wouldn't come back down to idle, really.

BANSHEE

i understand it going lean, but why is the computer riching it up so much??? never did it before

BANSHEE

i need help????