Hey guys,
I am new to tuning but starting to get comfortable with it. I have a 2004 Silverado 5.3L with a 4L80e and front mount turbo and 225/225 .581/.581 113lsa cam, SD 60lbs injectors. Running OLSD 2 bar tune.

The problem that i have is that my cruising afr seems to fluctuate with the outdoor temperature.

This morning I was driving to work at about 55* outside temperature and the log didnt seem too bad. Mostly -1 -2 afr error idle around 14.4. Then on my way home the temperature was about 75 and my afr error is up in the positives +5 and higher running in the 15-16 afr zone.

What is going on? My IAT sensor is relocated to just before the throttle body.

Ive attached both logs and my tune. Any help or suggestions.

Also I seem to be getting some random KR just cruising around when i lean into the throttle, you can see it in the logs. But if i go WOT there is no KR. I am wondering if this is burst knock retard?

 

That is one of the side effects of OLSD, 02 sensors are no longer being used to make fueling corrections. One table that is often messed with is the Cylinder charge temperature Bias table, this table determines whether IAT or ECT is referenced or a combination of both. Thing is, when you change any of this table you have to retune your VE all over. I can email you my Charge bias table for you to try if you want, send me a PM with your email.

 

With the IAT being right in front of the throttle body, why don't you turbo guys just turn the cylinder charge temp complex model off? That way it only uses the IAT reading insead of using a calculation?

Just wondering since I don't have a turbo or any kind of FI... yet. Is it because of a heatsoak issue?

 

It might be worth a shot. I read on hpt forum that i may have more fueling swings with it disabled and soley relying on the IAT but some people say otherwise so I will give it a shot.

 

If it only uses the IAT then you will have larger swings in your AFR based on outside temp, if it is only based on ECT then you will have to tune out some heatsoak issues. Try taking it to 0 or 2 and you will find out.

 

Thats strange?
I havent had any of those issues from 25* to 100*.
Efi live cos3 olsd uses a IAT fueling table to adjust it. And it works.

Wonder whats up with hpt?