100% injector duty cycle

[420_240]

I am trying to figure out why I'm hitting 100% injector duty cycle showing on my powerFC... Not sure if i just maxxed out my 555cc injectors at 371HP or not....

-duty cycle is set at 66% @ .15m/s lag-fuel pressure is 43psi w/o vacuum-walbro 255lph pump that has been hardwired to the battery-brand new fuel filter

[Joe]

what about your fuel sock/strainer filter? when was the last time that was changed?

duty cycle SHOULDNT be that high with injectors that big.

[420_240]

I believe i used the one that came with the walbro kit... that was installed roughly 2 years ago

[Carl H]

at power like that you should be in the low 80% duty...

[gawdzilla]

is your tune right? you probably have a rich spot on your map, or your map is just rich in general. i was hitting mid 90s, sometimes upper 90s depending on outside temps and was putting down 404. its very possible they are maxing out.

[420_240]

I think it's the tune honestly... I got my knock problem taken care of by installing a z32 maf...

I bet you're right gawdzilla... Most likely there's a rich spot on the map... somewhere around 5000-6800rpms.. and then i start to lean out according to my a/f plot from my tune

[Carl H]

something still isnt right man, even with afr's in the high 11's it still shouldnt be hitting max duty.your injector correction is proly fuxored, the power fc doesnt handle progressevly larger injectors very well, i have 720's and when i set the injector correction accordingly it would try to idle at 19:1.in the end i said eff it and set the correction manualy by warming up the car and then changing the injector correction till i got to about 14:1 idle then changed the delay till i got 14.7:1 or so at idle...retuned the whole map and havent had a problem since.

[420_240]

Could this maybe have something to do with adjusting the z32 maf under settings -> airlow -> vg30 -> voltage/air %

at about #17 on the x-axis in my injector mapat about #15/16 on the y-axis ... it's been set at 1.49 which, according to apex'i formula 14.57/ x = desired a/f ratio

I guess that would be about 10/1 ratio where i think i'm getting the spike in duty cycle.... does this **** sound right... i'm still learning about tuning

[gawdzilla]

you really cant do it that way. you need a wideband, a long straight road or dyno, and the datalogit. if you want to learn to tune w/ pfc that equipment is a minimum. think of the commander as a monitoring device, not something you make changes with.

in my experience you leave the maf calibration alone and mess with the fuel. your a/f is way bouncy anyway so that definitely needs to be fixed. i'm guessing the 100% is somewhere in the fuel map, causing one of your valleys in the A/F on the dyno.

[Carl H]

agreed, do not try and attempt to tune without a wideband or at a min an egt gauge.ive got mine setup so its 13:1 under spool from 3.5-4.3, then 12:1 from 4.3-5.7, then 11.5:1 from 5.7-8.5k redline.need to enrichen my part throttle map tho, little lean for my taste...