Leans out when its warm outside

[90AWDTalon]

My car is leaning out a fair amount at idle and cruise, and a huge amount at throttle tip in when it is warm outside. WOT seems to be fine. In the mornings when its cold my car runs great, no problems at all. Two of the possible culprits I was thinking of are, bad o2 sensor and bad FIAV. I currently am using the narrow band simulated output from my wideband o2 sensor, tomarrow after work I'm going to reinstall the narrowband o2 and see if that fixes it. If its the FIAV, I'll just block it off. What do you guys think of these two possibilities?

While doing a search to try and find the answer to this problem I found this,

If your car runs significantly stornger when it's cold there are 4 reasons.
1. The ecu runs the car richer when coolant temps are under 176 degrees. Coolant temp doesn't always coincide with block temps. Drive the car for an hour to get the block hot. Let the car cool off for a while, until the coolant temp has dropped to around 100 degrees. Now drive the car. Still fast like it was when you started it up in the morning? Well your block is still warm and close to normal operating conditions. Your car seems faster because it is running lean normally.

If my car is not getting above 176 degrees when it's cold out, I did my current tune when it was pretty cold and its been cold for a while so everything was working great, could the problem be that I did my tuning when the car wasn't above 176 degrees, and the ecu was adding fuel. And now that its warm and my car is getting above 176 the ecu is now not adding the extra fuel making my tune way off? I'm going to start paying attention to the coolant temp and see if its low when things are going good and high when its running lean.

What do you guys think about this problem?

 

[90AWDTalon]

I've determined that I'm running lean when the temp goes above 175. When its warm out my cruising temps are around 180-182 degress. It hasn't been as cold lately, so I've don't have much data below 175, but in the mornings, about 10-15 degrees warmer than it has been all winter until now, it does spend some time below 175 and at these times the A/F ratio is about right.

So what I need to do is figure out how to get my car to run a the proper temp. I tested my thermostat and it opens at 180 degrees. Currently I'm about 30% coolent and 70% water. Would changing this closer to 50/50 make a significant difference in the temps? What other options do I have?

 

[90AWDTalon]

Any Idea's?

 

[86MCSS]

Thats just the way tubro cars are. Its a fact of life. Thats why when you read post about people who check the stock air/fuel on cars and they say its running so rich. Its set like that from the factory so the car will run right even under the most extreme conditions.


All you can do is retune when the weather gets warmer or colder. I usually tune for an 11.8 air/fuel when its rather cold so if it does warm up a bit I will see maybe a 12.4 which is still safe enough for my car until I can take more time to re-tune it.

 

[90AWDTalon]

Thanks for the reply, but I'm looking for what I need to do to keep my coolant temps above 176 degrees.