O2's dialed in first?

[TommyT]

I'm a newbie to tuning. I've been reading the forum till my eyes are starting to refresh at the same rate as my monitor(headaches getting worse). Before I tune the LTFT's should I get my stock O2s dialed in if that's possible. I believe the histogram log should show them reading above 870mlv and below 890mlv? If they are out of range will my LTFT readings be more off? Can the O2s dialed in or just replaced(no DTC suggest they are bad). And just for the record, do I log LTFTs with or with out the MAF plugged in?

Attached is my last log and tune

Stock 2001 silverado 5.3 with K&N FIPK II kit,single flowmaster,(free mods)= descreened MAF, trimmed egr tube, TB coolant bypass.
Thanks for your knowledge and patients.

Tommy

[TommyT]

Ok, Maybe I'm totally off base with this question about O2 sensors since no one has responded.

TommyT

[5_Liter_Eater]

The fuel trims are a function of the O2's. I'm not sure what you mean by dialing in the O2's.

Or are you talking about WOT? Tuning WOT with the narrow bands is totally inaccurate. The narow bands could read hundreds of mV difference for the same WOT AFR with different conditions. If you must, most say that 890 mV equates to ~13:1. You should only tune WOT after you have gotten your closed loop fuel trims zero or slightly negative. If you have positive fuel trims then fuel is getting added to your commanded WOT/PE AFR.

[RedWS6 00]

It looks like your fuel trims arn't too far off. The O2's looks like the are occilating quite well so i would say they are working fine.

When the O2's are occiliating they are in closed loop.
Only in Closed loop the fuel trims are updated.

Now when you mash the loud pedal it will go into open loop, fuel trims will not be updated, the car/truck will run richer, but how rich/lean you cant really tell by the standard O2's. Really you need to use a Wideband sensor to tune WOT (Wide Open Throttle)

Looking at the Knock Retard you are getting, either you are running lean/ your timing is advanced too far or you have low octaine fuel.

Hope this helps......

[TommyT]

Info greatly appreciated. I think I found my answer to the maf or no maf question. set it to fail= 0 while tuning ltft's. Myabe my wife will give me a wide band for christmas. Were on the Dave Ramsey plan right now. Getting out of debt. I need to learn HP tuners so I can tune my '88camaro when I transplant an Ls motor and 6speed.

Thanks again,

Tommy

[RedWS6 00]

Info greatly appreciated. I think I found my answer to the maf or no maf question. set it to fail= 0 while tuning ltft's. Myabe my wife will give me a wide band for christmas. Were on the Dave Ramsey plan right now. Getting out of debt. I need to learn HP tuners so I can tune my '88camaro when I transplant an Ls motor and 6speed.

Thanks again,

Tommy

Yep good time to learn. I tinkered with idle, fueling, and done many logs. Then when i changed the heads and cam i had some logs to refer too, it certainly helped me get the car running quick after the install. Its worth while learning, if you took it to a tuning shop they will obviously charge you but i don't think they will ever get it as perfect as yourself. You can log any day you want, different weather conditions. I had to learn myself as no one in this area knows anything about these cars, heck hardly any have heard of Pontiac.
You've done the right thing getting HP tuners, its a good first step to modding. Good luck with your '88.