First let me get this straight, positive fuel trims are what, rich or lean? I've read on this forum that positive (+) trims are lean, is that right? At WOT my LT fuel trims went from 0.00% with the stock screened maf to .78% when I first installed the descreened Z06 maf to 2.34% at WOT 100 miles after installing it. So, I'm running lean with a WOT LT reading of 2.34%? Is that OK or should I use my Predator to get the LT's back to 0.00% at WOT? The Predator instructions say to increase (+) the "power enrichment" if you're running lean. This is what seems wierd to me, my LT's are 2.34% which is positive (+) and I'm suppose to go positive (+) with the "power enrichment" to get my LT's back to 0.00%, positive plus positive equals Zero? That seems *** backwards to me! Also, is there any corrilation to how much I'm lean and how much I adjust my Predator? I mean, if I go +2.34% on the "power enrichment" will that counter act the 2.34% I'm currently at and get me to 0.00% or will it take more or less tweeking? Now for my impression of the maf, I like it. Even though my LT's seem lean, the truck seems a little quicker and more responsive. I haven't done any more 0-60 runs but just driving around town, the truck seems better. It's going up hills a little easier and takes less gas to get the truck going, of course, my *** dyno may be off.
Jim

 

The reason positive fuel trims are lean is that positive means adding fuel to the lookup tables. When your engine is running on those tables the mixture is too lean so it has to add fuel to the mixture thus the positive number. Negative would be subtracting fuel from the mix because it is running too rich.

 

So I do need to go + on the "power enrichment"? Do I go +2.34 on my Predator to offset the 2.34% lean reading I'm getting?
Jim

 

I don't know Predators so mabey someone else can chime in here but if that makes it richer that that would be right. I guess you can try it and see if you get the results you are looking for.

 

Don't know about predator, but in edit the power enrichment only deals with fuel at WOT. If your ltrims are + at WOT, it means its already adding fuel to try and compensate for the extra air its seeing from that bigger MAF. So if you add more in power enrichment, it only gets richer.

The only way to be sure of what you're doing is to have a wideband.

 

GMCHASLS1,what road do you live off of in San Marcos?I used tp live off of Ranch Road 12 in the neighborhood called Saddle Ridge.Right acroos the street of the Phillips 66 goin towards Wimberly.I miss it so much there,especially the 6 acres I used to have and play on.

 

I thought a + reading (mine are 2.34% at WOT) means I'm lean?, and yes, the Predator only deals with LT's at WOT. When cruising at 70, the LT's are -.78% but when I go to WOT, they go to 2.34%. I already went + (pos) on the "power enrichment" +2.34% and the LT's went from 2.34% to 1.56% at WOT. Am I doing it right? I guess I could go - (neg) on the PR and see what the readings go to at WOT. I'm so confused!
Jim

 

If I understand it right, a + 2.34 reading means its decided its seeing 2.34% more air, so its adding 2.34% more fuel to bring your AFR right back where it was before.

But whos to say its not already at 11-1 AFR, and by adding fuel you'll be getting slower?

I'm pretty sure this is how it works, hopefully someone can back me up on it.

 

positive fuel trims is lean and neg ft is rich.

 

I live out Lime Kiln and Hillard road and I own 5 acres. I share your love for this area. As the crow flies I only live about 8 miles from Wimberley but would have to cross a private ranch to get there from here.