Thread: NEMU idle AFRs and Fuel Pressure

I am new to tuning and running into a few issues. Any and all insight would be appreciated. I want to get the best tune i can and learn how to do things the right way.

Info:
92 P10
88mm 12.5/1 VE
N1 cams
370cc injectors
N60 MAF
Stock Fuel Pressure or slightly over
AIV disabled

I have the car running pretty good on a basically stock MAP. All i have been changing is the current fuel injector size which is now at 290 and base is at 330. I am running really rich at idle, when warm it is in the 11s. Light load low RPM is in the 14 range, still under O2 control. Higher load mid RPM is 12-13s. After 6500 or so it starts to lean out, getting really bad at 7500, when i shut it down, it hit the 16s.

My load scale was off, max was 75 and i hit 98, i made the changes but have yet to run the car.
New TP Scale - 12, 24, 30, 35, 41, 46, 52, 56, 62, 67, 73, 78, 84, 89, 95, 100

RPM Scale - 800, 1200, 1600, 2150, 2700, 3250, 3800, 4350, 4900, 5450, 6000, 6550, 7100, 7650, 8200, 8750.

Now the issue, injector duty cycle hit 100%+ when it leaned out. So i can increase fuel pressure to solve this but my idle will just run more rich correct? Should i change the current injector size to get the idle in the 14-15 range? Or is there another way to change the O2 control portion of the MAP? Injector duty cycle at idle is at 2 now, can the injectors not go any lower and this is why it is running rich?

One thing i just remembered is the idle screw on the IACV is all the way in, if i bring it back out will it drop the idle AFRs? Will it not also increase the idle? Right now it idles right at 1000 RPM.

Thank you

Low voltage to fuel pump or bad fuel pump have seen this on turbo cars many times but more related to voltage supply to fuel pump

be sure to turn the o2 off while tuning any idle / cruise areas of the map, or even the injector size or kvalue.

also you must hit upload changes after each change to take effect, something i had to get used to coming from nistune.

i have my o2 disabled since it wasnt working anymore....afrs were grat but we have used a wideband

Voltage at the pump is 12.1 at idle, and goes up a little from there. It is a new Walbro 255 pump too.

I ended up raising the fuel pressure to 4 bar with the vacuum hose disconnected, then chanced the injector size to get the idle AFR to a good level. It is 13.5 or so at idle and gets richer from there. WOT was around 11.5 and only hitting 82% duty at most. I should be able to dial in the rest from here.