Over the past 2 years I have spent alot of time really paying close attention to my wideband A/F guage, even went so far as to test the Diablo Canned 91 and 93 tunes in the summer and winter months on a stock jeep (mine). What I found was that in the summer months the 91 tune is too rich but the 93 Pef CAI tune was dead on accurate at around 12.5at wide open throttle. Now that winter I tested them again but this time the 91 tune was fine in the mid 12 range, however the 93 Perf CAI tune was not safe at all in fact it was running 13.2-13.3 at WOT. I did several back to back test to make sure proper tune learning had come into play.

Now aside from the canned tunes this also applies to the CMR tunes. For the guy on the budget but wants the best bang for the buck getting a wideband plus a CMR tune just cant be beat. Having a wideband allows your CMR tuner to really tweak your tune. Now once you have that CMR tune you have to remember what I posted about the Diablo tunes in the summer and winter. So again I did some more testing on the CMR tune in the summer and winter. I have found that if the temperatures outside drop/raise 10 degrees I needed to add/reduce fuel by 1 point. For an example lets say a cold front rolls through Texas and yesterday it was 90 outside and my tune was dialed in at 12.5 A/F at WOT, but the cold front dropped it down to 40 degrees. I would then add 5 degrees of fuel in each RPM range. When Fall hits here this does happen sometimes here in Texas it will be nice and warm during the day and you hit the track at night and this is where damage can happen. Now most of you that dont have a wideband but do have a CMR tune I would be asking your tuner where they set your WOT fueling at or did they base your CMR tune off the 93 or 91 tune (very common practice and nothing wrong doing so). If you are just running the Canned tunes I wouldnt run the 93 tune in the winter.

Looking for the like button!!

I agree that a wideband makes it really nice to know where you are at.....especially if you hook it up to a Trinity and log it :D

I really need to get a trinity and a wideband next season to put this truck in the bottom 12's/high11's.

Dam Wade thats to much work for an old fudd lol.

Wade just for sh*ts and giggles have you ever tried this with the stock tune to see where it ends up? Also isn't the barometric settings in the tune supposed to compensate for DA changes in fueling?

My tune was set at 12.3-12.4. Yesterday morning I was hitting 13.1-13.2 due to 38-40* temps. I added 5% of fuel yesterday and got it back down to a happy number.

Wade just for sh*ts and giggles have you ever tried this with the stock tune to see where it ends up? Also isn't the barometric settings in the tune supposed to compensate for DA changes in fueling?

Yes I have its pig rich into the 11's like low 11's probably to protect it in the winter months from detonating. I wish the tune made the fueling change automatically due to change in DA/Temp but it does not.

I wonder where my jeep would sit today at -21 HMMM........Great advice Wade!

Now if i could get my jeep to start @ -21 and run like yours id be set.

Newfie.

Do what i do with out a wide band . I take a leak in my tank with every fuel fill up . Jk hehe .

Great write up Wade and thanks for the heads up ...

Do what i do with out a wide band . I take a leak in my tank with every fuel fill up . Jk hehe .

Great write up Wade and thanks for the heads up ...



I just called Santa and told him Paulo ONLY gets a wideband for Christmas.

Yes I have its pig rich into the 11's like low 11's probably to protect it in the winter months from detonating. I wish the tune made the fueling change automatically due to change in DA/Temp but it does not.
Back up there a second Wade....you said everything but the stock tune was leaner in the cold....the stock tune went rich.....I would say the PCM with the stock tune made fueling corrections in the cold which tells me that someone shut something off or didn't adjust the settings in the canned and CMR tunes.

might depend on how the tune is done. The stocker may make use of the jeeps ability to adjust to the stock target, but pinning the power enrichment tables to a certain target value, depending on your tuner's method, may not make use of the truck's ability at stock to compesnate for ambient conditions. Some say you can custom tune these and still have that variability, some modify tables in a way provide a certain amount of fuel, period, which requires modifiction for the July heat (pig rich) and the December chill (super lean) because of the changes in 02 density from when you had your tune done. Best bet is maybe load the Trinity up with the tunes that fit the weather, hot, cold and temperate and then you can just throw them in as the weather requires. Good protective measure to keep from your first blast of cool air being a bad event, especially if f/i.

Back up there a second Wade....you said everything but the stock tune was leaner in the cold....the stock tune went rich.....I would say the PCM with the stock tune made fueling corrections in the cold which tells me that someone shut something off or didn't adjust the settings in the canned and CMR tunes.

I didn't say that you asked what the stock tune looked like you didnt ask in what temperature I checked it in and I dont recall I just recall it was rich. If you'd like I can go back to stock tuning tonight when its in the 40's and see what it reads?

Be careful because the stock tune targets a richer AFR then most CMR tunes. Stock calibration richens up to ~11.8-11.6 at the higher RPMS if I remember correctly. Check your AFR vs commanded AFR to make sure it's actually getting what it commands. But then again, what do I know ;-)

J

Just noticed this myself on my tune when it went from 80* to 40* the next day about a week ago. However my question is would the change from the winter blend gas to the summer gas affect my wideband AFR that much? Jim where you at? The reason I ask is cuz after 4k rpm I am seeing high 11's then down to low 11's . Not sure if me changing out my driverside rear o2 last week could have an effect on this as well.

What do you guys think?