marine02ss

iTrader: (3)

I finished another customers car,02"Ram Air stock 346ci,AFR 205s,Trak cam,Fast 90/90, pacesetters 1 3/4 full exhaust.We managed to pull off
422hp@6400 [email]385tq@4600. Afr locked at 12.8 thru 4800rpm then 13.2 till 6600rpm.Im not a professional tuner or anything but I can manage my own.I have one problem that doesnt go away,maybe some of the more experience tuners can chime in.I am having a lean condition occuring from 3600rpm till 3900rpm,goes up to 14.8 then I get a knock retard of -4 degrees AFR goes down to 11.00 then back up,finally AFR levels off to 13.2 at 4600rpm till redline.I have 26deg peak power and 23 degrees peak torque.I dont understand I lowered the timing,added more fuel,checked fuel pressure constant at 58-60,the most I seen drop was to 55psi.Anybody had this problem before?Overall the car runs great and smooth.I logged the dyno runs when this lean condition occured, O2s were at 945mv and 890mv.

txhorns281

iTrader: (12)

Timing won't cause your A/F to dance around that far. How exactly are you adding fuel at the affected range? Stock injectors? High mileage? Do you have any logs of the pull?

marine02ss

iTrader: (3)

I do have the log how do I post it?

ChrisS@sdpc

A log would be good. Is this on a dyno run or under what conditions are you experiencing the condition? Did you tune the VE table? You may be experiencing some issues in transition from VE/MAF to full MAF fueling. I have some logged data demonstrating/showing very little AFR affects from huge timing changes (only .2 AFR change with timing varying from 9.5* to 36*). Besides, how does changing the spark alter the amount of air or fuel that entered the engine.

To post the file: under the area where you type in your message, there is a section titled 'Additional Options'; In there, you can 'Manage Attachments' HTH