CLSD tune runs great 30 min later rich at idle

[louis]

Hello.

Tuning in autove and tune is beautiful for 30 min, Intake air temp and water temp do not change either. If I sit at a lite after 30 min I can see the my lm-1 reading 12.0 and even down to 10.0 after a period of time driving it like this. Then of course plugs foul out.

I park the car come back out to test it and good for another 30 min before it does it again.

Doesnt seem right in closed loop after 30 min it starts feeding it fuel at idle and when I give it the gas it goes back to 14.6 untill I let off the throttle again. All this only after 30 min of great running.

I would like to solve this before I go back to open loop and am I right in assuming that open loop running short and long term fuel trims would adjust this anyway?

Thanks

Louis

[ringram]

If your cam is larger than stock o2 sensors will read wrong and try to adjust due to overlap, unburnt fuel and o2 in the pipe. You might want to go open loop or fuel via TPS near idle to sort that out.
At least thats one possbility anyway.

[louis]

I get what you are saying and looked into this but what I see is all fuel and tp are set to 0 and not correcting anything. Would you know which table I should try to start correcting it thru fuel vs tp?

My cam isnt stock but not radical either. I am running a 535 lift blower cam with an F1-C blower and the car runs unbelievable for 30 min.

I dont hear an exhaust leak at all but maybe after 30 min it is hot enogh to open up somewhere. and then the os sees a lean area and tries to correct even if the leak is upstream from the 02?

Thanks for your reply.

Louis