Air-Fuel Ratios for Stock & FP Tune Cars

[TicTocTach]

I haven't done any datalogging with my car - I don't think I have any way to do that with the tools I have, and have purposely kept the mechanicals as close to stock as I can to keep reliability close to factory levels. I do have the FP tune though, and have recently been keeping an eye on A:F ratios that display through the dash. I think what I'm seeing is normal for this platform, but not what I expected to see - so I'm here for a reality check.

What I'm seeing is that for most part-throttle situations, AFR's are staying in the 14-13:1 range, even with some boost building. However, actual WOT is showing closer to 10.5-11:1, which IS what I expect to see. It's the part throttle, light boost (5-10 psi) 13's that are throwing me off. I expected to see richer AFR's than 13:1, but that may just be how the Eco 2.3 runs. Cylinder head design, quench/squish, DI fuel management - all those things have greatly improved over the years and I'm assuming that Ford is taking as much advantage of that as they can.

So, enlighten me. Am I seeing AFR's that are reasonable for these scenarios, or do I need to do some detailed datalogging to see if there is a problem going on?

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[FreePenguin]

Seems normal

Have you ever seen something like this happen curious?
I have fp and my tune does this 12-15-12-15-12 for a few seconds randomly as I’m driving no rhyme or reason

 

[EFI]

So, enlighten me. Am I seeing AFR's that are reasonable for these scenarios, or do I need to do some detailed datalogging to see if there is a problem going on?

I would also like to see more linear AFR enrichment, but that's not how Ford does it. Their power enrichment is only at high throttle positions and higher RPM, not in the part throttle or lower RPMs.

If they back it up with a warranty, I wouldn't worry about it.

 

[TicTocTach]

Seems normal

Have you ever seen something like this happen curious?
I have fp and my tune does this 12-15-12-15-12 for a few seconds randomly as I’m driving no rhyme or reason

Wow, I have seen nothing like that before - is it storing any codes? That seems like a strange O2 sensor response, but I guess it could actually be related to fueling. Strange that the sweep is so slow and regular...

 

[FreePenguin]

settled it, im going to change the o2 sensor, I think it happened within last 5 k miles. = o2 sensor is prob culprit. nope, nothing drives odd or anything just does it while cruising sometimes, like its resetting itself, then goes back to 14.0

 

[FreePenguin]

does your car idle like this? I wonder if im alone, 13.9 to 14.3-14.4 I may need to change plugs if mine wildly varied compared to yours
im ford tuned.

 

[GuardEcoBeast]

You should probably put those tune plus ngks in it. Clear it right up.

 

[FreePenguin]

You should probably put those tune plus ngks in it. Clear it right up.

no interest running colder plugs. thanks though! ford perf told me to run oem heat plugs. they said its tuned for them. I put oem heat plugs in, and I believe it was idling same way as soon as I put these plugs in, never looked at afr before I put new plugs in to compare

the car runs smooth and drives fine. just wondered if 14.4 is too high/dangerous for leanness. driving it goes from 13.9 to 14.3 or so cruising / cruise control

 

[EFI]

I wonder if im alone, 13.9 to 14.3-14.4 I may need to change plugs if mine wildly varied compared to yours

That's perfectly fine idle AFR.

 

[TicTocTach]

no interest running colder plugs. thanks though! ford perf told me to run oem heat plugs. they said its tuned for them. I put oem heat plugs in, and I believe it was idling same way as soon as I put these plugs in, never looked at afr before I put new plugs in to compare

the car runs smooth and drives fine. just wondered if 14.4 is too high/dangerous for leanness. driving it goes from 13.9 to 14.3 or so cruising / cruise control

I think mine idles / drives about like that. 14.7 is the "ideal" ratio for the cleanest emissions, so that's likely what Ford was trying to stick to. A tiny bit richer to run a bit smoother I'd bet. Anything higher than that I'd worry about unless you're at really light load cruise.

 

[FreePenguin]

I was worried for nothing, I have been switching around set ups, downpipes, o2 sensors etc.. I was just doubting my own cars system. It runs smooth, drives smooth, I need to quit looking at AFR gauge. im going to keep the temp gauge up instead of boost/afr here on out.

 

[TicTocTach]

I think it's good to keep an eye on things from time to time. I'm embarrassed to admit that I didn't pay attention to my AFR at all until AFTER I swapped out the low pressure fuel pressure sensor last week. I did notice my car having an occasional idle dip down to 500rpm or so where it was a little more rough, but that seems to have gone away now.

FYI, I changed my sparkplugs out to iridiums a year or two ago and I think that also helped idle - mostly because I had them gapped properly. The OEM's were close, but not consistent. I'm trying to refine every little bit that I can to make sure the whole system is performing the best that it can.

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