06MonteSS

When using the Predator and adjusting the injector slope -- if I had to go negative on slope (cuz I had + trims), does that mean I need to go positive (rich) in the PE ranges??

I've seen conflicting statements...

...the Diablo book and RWTD site say that if you have positive trims - you go negative on injector slope (to zero them out) and you need to LEAN OUT (go negative) in the PE ranges as well.

...but I've read online forums where users say that when they go negative on injector slope, they need to go positive (rich) in the PE ranges.

So which is correct??

Thanks!

p.s. - at WOT, my trims lock at 0, my stock O2 is 860-880, and AFR is 12.2-12.6

06MonteSS

ok, got the scoop from diablosport (Johan's tuning doc)... basically yes - if you go negative on injector slope, you need to go positive (rich) in the PE ranges by the same amount -- and vice versa.

so the manual says the opposite, and is wrong.

Sneakyws6

I talked to mike the other day and that about what he had told me. Run the injector slope - to correct any positive STFT or LTFT's and then use the enrichment function to help zero in the LTFT's.

I am still waiting on them to tell me exactly what the injector slope function does to the tune.

06MonteSS

negative injector slope makes the pcm think the injectors are smaller - this will alter the pulse width so the injector will squirt more fuel, correcting for the positive fuel trims.

positive injector slope makes the pcm think it has larger injectors and thus reducing the pulse width to supply less fuel.

sprayjunkie

^^Thats it^^