jhysock

can anyone tell me how if possible to tell what size injectors are in a car 89 mustang 302 with no crazy mods just cold air intake, svo heads, cam (f303 i think), full exhaust, ignition, chip, underdrive pully. my plugs are white and i've gone over and over everything only thing i can think of is maybe injectors are blocked or are to small i would like to step up in size if it would make more power and fix this problem.

TrimDrip

what color are they?

if you can ever run a KOER, you can do the balance test for the fuel injectors to let you know if they are out of balance

luckythirteen13

iirc, stock (19#) is yellowish orange and 24s are blue. with the mods you have, i would run 24s. once you upgrade h/c/i, even if its a mild combo, its a good idea to upgrade to 24s

you might also want to look at your pump. when i did heads and intake on my motor i did 24# injectors and went to the track. ran the wide band and it says i was 22:1 afr. i increased the fuel pressure every pass till i hit 55psi and still was getting a 20:1 afr. thats when i realized the fuel pump just couldnt keep fuel pressure up at higher rpms

mattdel

no reason to upgrade injectors yet. 19#'s are good to around 300whp, they aren't anywhere near max duty cycle with your mods. check fuel pressure and volume.

jhysock

whats the best way to check both i have a fuel pressure gauge what or how do i do the rest ?? also car was set up like this for the last 3 yrs and plugs looked good is it possible that changing plugs from autolite to motorcraft affected this??



dumb as a rock when it come's to fi

mattdel

start with slapping the gauge on it and taping it to the windshield, then go out for a little joyride around the block. 39 psi is optimal stock setting.

jhysock

fuel pressure seems ok it drops a few psi under higher rpm 3/5psi can ther pump still be going (not enough vol) also wath would be the better fix new intank high vol pump or would an external pump work

AdderMk2

new internal all day long... get a walbro 255