i was wondering, if I have tuned my car to run within +- 2% LTFT and STFT does whatever it wants, usually less than +- 10% do i have to worry anymore about being over rich or lean during non boosted operation. it's wierd, my gas mileage has pretty much ate crap, i have 440's i am leaned in the 40's for most RPM's i run 25psi idle FP. I have not boosted yet due to the rebuild, but i noticed that my gas mileage has gone to poop.
thanks
james

If your LTFT is low from idle to 0 psi, then that is the best you can do for non-boosted operation. The ECU will be able to adjust to deliver the proper amount of fuel. If you have only checked LTFT at idle, be sure to check it while cruising at 0 psi.


Corbin

'95 ESI-T
HRC+FMIC+ETC...



Gimme fuel...Gimme fire...Gimme that which I desire

corbin,
this is at all RPM's up to about 5000 so far. i was kind of puzzled because my gas mileage has gone down alot, from like 350 miles per tank to like 250. but i have not driven in boost yet, so where's all my gas going? DOH! my LTFT has pretty much stabilized and the STFT is the one doing all the fuel trimming. i'll datalog again tonight and see if there is any difference.
thanks for the info!
lates
james

A bad O2 could give you crappy mileage. Perhaps the injectors aren't spraying right at that fuel pressure. Its a little on the low side for recommended operating pressure. Are you breaking the engine in? Maybe excess fuel consumption is normal during break in (extra friction)? Just guesses...


Corbin

'95 ESI-T
HRC+FMIC+ETC...



Gimme fuel...Gimme fire...Gimme that which I desire

hmm possibly, my front 02 sensor is good, my rear o2 sensor may be a little nasty, but not sure, not getting any CEL's maybe i'll gumout my o2 sensor or something and see what happens.
thanks
james