tunedek

i recently installed a new set of 550CC injectors and a wideband. i am street tunning through a s300. i have been running, and still am running a factory ITR program. but the car runs super rich according to the wideband.

my questions are ...
is it normal that i would run really rich just because i changed injectors? according to my wideband i need to seriously decrease fuel. i am running all motor for now.

secondly, what do the numbers in the fuel tables represent? for example in column 13 at 8900 rpm if i remember correctly it has a number = to 1170. what is that 1170?

and lastly, how do i verify my wideband is correct? the values on the gauge seems to be richer slightly than that of the s300 readings.

nfn15037

The numbers are arbitrary numbers that represent injector pulsewidth. Some people call them 'fuel values' but in most Honda ROM editors, they don't actually mean anything specific. Larger number = more fuel, smaller = less delivered per injection event.

You need to rescale for your 550cc injectors.

tunedek

I kinda thought so. Thanks for your response. Being that the number reflect pulsewidth this would make sense that while I told the S300 that I am using 550's I am still running really rich. So it sounds like I have to lean out alot of fuel. Is it possible to figure out a mathematical ratio for the differences between the old 240 and new 550's?

nfn15037

240/550 = .436

Multiply the whole map by .436, although there should be a function to scale the entire map int he software.

1C9R9X1

hes right there should be a space where you enter your fuel inj. size .it will get you in range

v4lu3s

if you are runing the p73 base map for the s300 it is also rich too, even before changing injectors.

tunedek

i think you are right. im ls/vtec ... not factory guts but near expected compression for a "factory" ls/vtec. im going to switch to a p30 base map and play around with that and see how it goes.

appreciate everyone's help. the idea of those number being meaningless .... well actually reflecting a value of pulsewidth makes perfect sense and really helped me understanding the fuel maps. thanks.