AFR at idle 16.0/.2

[Dert]

hey guys, I just hooked up my aem uego and ecmlink today and my idle afr is 16.2 ish. How do I go about achieving 14.7 with link? I searched on ecmlink forums, read as much as I could find but came up short, I even watched the demo videos but in all of them they were already stoich...need helps as to what I gotta do to lower it, thanx-Gary

 

[fullCircle]

do you know what the stock O2 sensor readings are?

are your current readings being taken after a cold start or after the car has had a chance to warm up to operating temperatures

 

[Dert]

When I first turn the car on it reads 14.7 but then after 30 seconds it starts to climb and after 2 min it bounces from 16-16.2 and when I cruise it is slightly, not much, lower and when I accelerate and let off the gas it maxes out

 

[viprez586]

Target AFR is 15.7 I believe.

Double check for all exhaust leaks post O2 sensor.

Sea-foam helps discover exhaust leaks.

Also do a boost leak test.

 

[DSMnoobsause]

ya ive tuned my car for 15.7 on idle and light cruise. now if your going that lean under load then you have some issues ha ha. but i don't know if i would worry to much about that if its running good.

 

[Dert]

it seems to run fine, I do infact have an exhaust leak where my downpipe bolts up to to the rest of the piping, I'm guessing that is the culprit, I would post a small 3rd gear pull on here so someone can tell me whats going on as I just started using it so I have no clue how

 

[Imback]

Fix your exhaust leak and then post back. Also the ideal afr at idle is 14.7

 

[fullCircle]

are those readings straight from the AEM WB or the stock O2 sensor (unless you removed it)? What im trying to get at is what the stock O2 sensor is telling the ECU. A partial working O2 sensor could be sending a rich signal to the ECU thus explaining the slight lean issue. exhaust leaks past the O2 housing usally won't cause a problem but any leaks before the stock (ECU)O2 sensor will.

 

[MagickMan0730]

I dont really know about tuning yet but Im gonna give my 2 cents. Did you maybe check the BOV as well or where its recirc'd? Or for a vacuum leak? My guess is because where it maxes out BETWEEN shifts. Same kinda result like when your venting to atmosphere??

 

[Dert]

I have the stock front sensor in the front and the wideband in the rear...about 6 inches after the leak

 

[Colt4G63 also]

Fix your exhaust leak and then post back. Also the ideal afr at idle is 14.7

+1 An exhaust leak before your wideband could suck in air and skew you readings.

Or if the problem persists:
If your "STFT" and "LTFT lo" are sitting in the middle, and your front O2 sensor is working, then you shouldn't need to adjust your idle AFR. The ECU does it automatically. If the fuel trims are far from zero +or- more than %5 LTFT, and maxed out on STFT, then you would need to make adjustments.

The STFT will make quick adjustments up to %16-%25 (depending on what version) to try to keep your idle and criuse AFRs at stoich (14.7:1). If STFT is sitting consistently in one direction + or -, and the car is at operating temp (186 F or higher) then it will correct by adjusting the LTFT (long term fuel trim) untill STFT (short term fuel trim) maintains at or near zero.

Thus, as long as you have driven the car while fully warmed, LTFT can be used as an indicator as to what settings you would want to change in your MAF correction table.

 

[VETTE_50_TH]

16 on cruise isnt bad. Thats a good, maybe a little lean at cruise. Should be getting good gas mileage.

 

[fullCircle]

I have the stock front sensor in the front and the wideband in the rear...about 6 inches after the leak

Not to beat the dead horse.... fix the leak so your WB O2 sensor reads correct. While a WB is an absolute necessity (IMO) for tuning... a bad or partially bad stock O2 sensor will still send incorrect readings to the ECU. garbage in, garbage out. You can do a "band-aid" tune to compensate for a bad O2 unless it's completely AFU.

I realize that you may not even have a problem with the stock O2 sensor and thats why i was asking for the reading for it, making sure it was telling the ECU the correct info to begin with. this will save you allot of headaches when it comes to tuning. The WB sensor is like a second opinion thats giving you the Eddie Murphy "Raw" version of your AFR's...so to speak

I have a feeling fixing the leak will bring it into specs.

 

[Dert]

I finally located how to bring up different things while logging, one of them being the afr estimate, it was at 15.7 on link and with a little tweaking with global and deadtime (ecmlink demo video said to leave it at 0 with stock injectors)I got it to fluctuate between 14.1 and 14.8,I didnt change global much (-5.7% or so) and deadtime is 30, but it worked like a charm, then I did a 3rd gear pull and had a knock reading of 8.6 wich is probably alot, that was at 5600 rpm range, and with a little tweeking on that I got it less than 1 so a little more and should get it to 0...I'm really liking the world of ecm link, my car used to be running 100% now its 200 ...now if the 650cc injectors I bought would hurry up and get here...thanx fellas