I put my car on the dyno the other day at my local shop to do some tuning. The a/f was in the 10's until about 5500 rpms where it leaned out and went into the low 13's. I took some fuel out of the rpm band in the 10's and got it into the low 11's. I data logged all three passes on the rtek but the last two we let out at about 5700 when it went lean. The first run only revving to about 6500 it made 339/282. The rtek seems to only read 15.8 psi and my question is would anything above that cause it to go lean? I have the fuel correction maxed out and no matter how much i put in it doesnt seem to change. I have been trying to diagnose this problem for a few weeks now. I have put it an adjustable regulator, new fuel pump, and all new filters, thinking it was a fuel psi problem. I hooked up a guage to the regulator and ran it up under the hood where i could see it. I set the fuel psi at 45 psi at idle and under load it goes from 50-65 psi increasing with boost and never comes back down till i let out. Are there any suggestions? Tomorrow ima turn the boost way down and try it again.

Quick mods list
rtek 2.1
rc 750/1200 injectors
walbro 255
aeromotive fuel reg.
bnr stage 3 @ ~16psi
godspeed fmic
racing beat turbo back
Intake

 

well i looked at the FAQ's again and like i remember the map only reads 14.7 psi. I thought that the computer just uses the last value that it saw through the rest of the rpms.

 

after that the computer will only make corrections on that last row. Anything above is playing with fire. Put alot of fuel in the top cell at the 5700 mark and see what it does.

 

Did you rewire the fuel pump? Sounds like a loss of fuel pressure. High flowing pumps are still greatly affected by voltage. My car had similar leaning out problems until I rewired my Supra pump.

 

The last corrections are held past the last cell.

 

in my first post i said i was chasing a fuel psi problem for a few weeks. The guage i put on it yesterday said i was running 65psi all the way till i shifted. Is that enough? Im not sure how much these motors actually need. In the top row of the rtek from 5500 on up i have the injectors maxed out on the fuel correction.

 

What is your injector duty cycle up there?

 

i didnt data log the duty cycle i was going to do a pull on low boost and data log that