Why would my truck give off a inaccurate AF ratio. I had my chip reburned for my mods, truck felt strong no pinging, tips were black. After about a mont I took it in for a dyno tune, on the first pull he let off because a 13 AF was coming up. So some fuel was added to a 10.5 AF, and i was now making less power than before the new mod, and felt slow. I 've checked the MAF and tried 2 wideband sensors. Ideas?

 

What's so weird about that? You're quit rich, I will say that.

 

Exactly.......your story seems perfectly logical. You are richer and making less power......makes sense to me.

So what is the matter.

--Joe

 

well an AF of 13 should of blown up the motor,( according to my tuner), and from his expierence I should of gained power going form a 13 to a 10.5 insted it droped by 20 hp.

 

A leaner A/F will make more power than richer A/F.

--Joe

 

Slo-Joe,

Not always the case,i have had many chips dynoed by different tuners that were very lean and they made less HP and Torque than some that were in the safe range.Leaning out a chip is only 1 of several ways to make power as you know.

 

Well OK smart guy.......I know that 2 different chips could do that. But on the same chip with the same amount of timing.......a richer program will make less power than a leaner one

Jeez you gotta be so damn specific nowadays

--Joe

 

Chad, the exhaust tips will pretty much always be black. Unleaded fuel doesn't read like the leaded fuel of old. It's also really hard to tune by looking at the color of the porcelin on the plugs. It's really easier to tune unleaded by the the color/erosion of ground and center electrode.

It seems the 10.5 is too rich. Mine runs at around 11.2. You might try to lean it out a little to bring the power back.

Make sure you don't have any air leaks in the intake system. That will make a/f ratio inconsistant. Also, I think Lightninrod was having some problems with his IAC, that may have exhibited similar problems.

 

Also, I think Lightninrod was having some problems with his IAC, that may have exhibited similar problems.

Jay, not me, at least not on my L........? I have had IAC problems on my 91 Z281LE and my Saab(both gone now) but not on the L. Btw, a dirty or worn IAC causes a surging idle.

Dan

 

All trucks are different!!! You say that you had it re-burned and were driving around getting on it W.O.T. with no problems( I assume??? ) If this is so then I would guess that your truck is like mine....It only makes good power if its LEAN...I run my A/F ratio @ 12.0 no more, no less!!! If you were doing fine with the chip "the way it was ", then why make such a dramatic change??? I say take the A/F to a 12.0 to see if you get any power back and that would keep it ALITTLE safe too!!!

Hope this helps!!!!