AFR difference between the banks

[bleunetizen]

I find my AFR is always 0.5 richer on bank1, is this common?

this happens in open loop only, they are pretty close to each other in closed loop.

also found that MAF reading is slightly higher on bank 1 than bank 2 under open loop.

anyone with some ideas?

[Chuck33079]

My tuner found a discrepancy as well. Apparently Uprev can only adjust fuel globally, so bank-to-bank variation means you have to une to the leanest bank. I'd assume there's a certain amount of variance that can't be avoided.

[bleunetizen]

thanks for the info

[Chuck33079]

Ecutek apparently can adjust fueling by bank. Mine wasn't a half point off, so it didn't make a huge difference in my tune. A half point is a pretty big difference.

[Megan370z]

Originally Posted by Chuck33079

Ecutek apparently can adjust fueling by bank. Mine wasn't a half point off, so it didn't make a huge difference in my tune. A half point is a pretty big difference.

Uprev can adjust fueling on each individual cylinder... just saying

[Chuck33079]

Originally Posted by Megan370z

Uprev can adjust fueling on each individual cylinder... just saying

Interesting.

[Megan370z]

Originally Posted by Chuck33079

Interesting.

top right

[Mitco39]

Originally Posted by Megan370z

top right

Shouldnt the engine have long and short term trims that should handle these inconsistencies?

[roplusbee]

I really depends on how far the tuner is willing to go to adjust/set your AFR targets.

Mine is about .5 off toward bank 2. Bank one being the richer bank. Omar has been playing with my car for a bit since it has been at UPREV for the past few months. I will report in once I pick her up.

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[DOOMMONKEY777]

Just did this cylinder adjustment to 104.69, A/F ratio is exactly the same, before it was about .50 different, also i can hear the engine running more smooth rather than like a tractor.

[Jordo!]

Yep. There's always potential for some variance between the banks -- not sure if .5 would be considered unusually high deviance tho'.

Can you monitor fuel trims for each bank -- how close are they?

Also, one MAF sensor may need to be cleaned or you could have one extra dirty filter.

[DOOMMONKEY777]

Yeah i thought it was the filters as well so i looked at them they looked barely dirty and i have found a few tree leaves, cleaning that barely did anything. There was notice, but u can still hear that something was off. The A/F logging showed it was off by~-/+.50 from other bank. Found this post and adjusted it, now its right on the money they r both the same ty very much, if it wasn't for this thread and ppl's shearing i don't know when i would have figure it out.

[bleunetizen]

I also used cylinder trim and got both banks to similar A/F now.

actually I reduced whole lot by around 3% and that put the car to match up very closely to the target A/F, without touching the fuel correction table.

[Mitco39]

HC_416,

I dont think any exhaust leak would cause this. The ECU knows its running rich but yet its still trimming like its lean. Even if you had a big leak the ECU should do whatever it can to meet the target AFR, not push itself away from it.

Do you have a cat delete? are both downstream O2s roughly in the location they would be stock? I have a BP kit and both of my downstream O2s are actually in one bank. I think this might be causing my issue, however if I can find someone else who has both his 02s approximately in their stock location with this issue then that would rule this out.

The way I see it aside from the possible secondary cats causing the issue there is nothing else on the car that could possibly contribute to this. A pin hole leak or even a big leak would make the ECU work overtime to meet the target AFR, not push itself away from the target. If that makes sense.

[hc_416]

Well I hope you at least get it figured out. I have had this problem since January and have been nit picking at it cause of time and life. More than likely wont get it fixed till the winter.... Also I think I should read better, but since you were seeing the kind of of the same problem I figured I would put in my 2 cents just to try to help out. GL man hope you find it. I know I made 309 whp on a mustang dyno and that was with no parts and this air leak. Once I figure it out I'm hoping for 330-340 WHP. I did a lot of improvements.