lean A/F ratio? a question for the tuners.

[larrym1961]

I have allways suspected my Mustang has run lean because after pulling plugs @ 5000 miles they looked almost brand new!

Today I finally installed my Wide band 02 gauge. and I am what I think is correct, a super lean condition. @ idle the led dial is pegged @ 24 and it is showing over 18:1 on the digital read out. when I stabb the throttle it will go to about 12:1 then back to over 18:1 @ idle.

Am I right? is this way to lean and if so how can I get the mixture to richen up? If not mechanical, I do have the SCT Eliminator chip, can I send it back to them and have the mixture fattened up by the ECU?

I know the savy Mustang tuner out there should know about what the ratio these 5.0's should be running and how to get it there!

Thanks!

 

[lancec2c30]

I am guessing this is an AEM wideband?

18.1 at idle is pretty lean, but I wouldn't call it dangerous. Do you have any vacuum leaks pre wideband? That would cause a lean condition. What does the gauge show under part/full throttle conditions?

Now if you're seeing 18.1 under load, that would be a problem.

 

[larrym1961]

Yes, it is a AEM Wideband. And there is no vaccume leaks that I am aware of. As far as the idle it holds steady @ 900 RPM.

@ 2500 RPM the wideband showes a 14:2 ratio. @ wide open I am getting a 10:1 ratio. @ idle 18:1 or more.

My feul pressure is adjusted to 48 psi w/o vaccume, and 42 psi w/ vaccume.

Does this sound like there could be a possible vaccume leak somewhere?

 

[ID89GT]

That's pretty high for fuel pressure

 

[larrym1961]

That's pretty high for fuel pressure

I had it set @ 42 W/O vaccume, 38 with. I increased it to 48 w/o-38 w to see if the increased pressure would do anything. None at all. So it's back to the original setting.

 

[2000xp8]

Pull the chip out and see how it runs.
There's nothing in your mod list that the stock computer can't handle easily.

 

[larrym1961]

did that too, same results.