IAT Correction playing havoc with my AFR's

Vtec6000 · Post by **Vtec6000** » Sun May 02, 2010 11:02 am

I had been told before to leave IAT correction table values alone but the stock values are giving me strange AFR's. Basically I let car fully warm up as normal then tune idle to near 14.7afr and proceed with rest of tune however after I would do a run and then pull in to check datalog the idle would be rich due to the lower IAT reading after run(car is NA) then as im making changes and IAT is rising and making AFR go leaner which is ok but at one point when IAT reached 48*c the AFR got very lean 15.9AFR. The IAT correction caused the lean condition when hot both at idle, low load and high load when driving once IAT's were above the normal 18-20*c I can see this been a big problem on a boosted motor if your sitting waiting for your turn down the strip and IAT's are on the high side. What do you guys recommend to do? Alter the IAT tables?

Vtec6000 · Post by **Vtec6000** » Sun May 02, 2010 11:09 am

Here is the Cal. and a datalog showing at start where im pulled in with car running and IAT's are rising causing the AFR's to get very lean then I drive a short distance to lower IAT' and pull in again.

Post by **Gaskleppie** » Sun May 02, 2010 3:48 pm

If you got problems with heat soak, get rid of the heat soak, but dont try to get rid of it by changing the IAT tables. You can mount the sensor in the intake piping to make it a lot better.

Vtec6000 · Post by **Vtec6000** » Sun May 02, 2010 5:00 pm

Gaskleppie wrote:If you got problems with heat soak, get rid of the heat soak, but dont try to get rid of it by changing the IAT tables. You can mount the sensor in the intake piping to make it a lot better.

Thanks for the reply. The IAT sensor is actually located in air intake pipe... Should there be such a variation between 18*c and 28*c as thats where the air temps seem to be most the time unless parked up for awhile left running then IAT rise to high 30's

JaredKaragen · Post by **JaredKaragen** » Sun May 02, 2010 6:43 pm

Personally speaking, I always zeroed the ignition corrections for the higher temp end of the scale, it has never caused me any major issues.... Same with the fuel side... I just leave small amount of changes on the high end of the temp scale and trim if needed. This was with the plenum mounted sensor.