MSefi.com read only forum (Jan.15,2018)

Does anyone use the IAT correction for fuel? I am using MS2 with a mild 454 chev. I have the iat sensor mounted to the inlet side of the air cleaner and the system has and inlet tube from in front of the grill to get air. I have noticed that when my iat gets up to around 100f the A/F goes lean. The higher temp comes when stopped idling or going very slow. I have not had the car running when the outside temp is very warm so no test there. The temp I have been in are outside 40-60 f. Just wondered what others have found and what they have done for the correction.
Thanks

It sounds as if the IAT sensor is absorbing heat from the manifold; try a higher % of correction at high temperatures.

Yes I think that is what is happening. I have added a % increase starting at 85 and going to 8% at 100. That seems to make the A/R act ok. I am also going to take part of the ducting off and let it get air from the engine compartment and also move the sensor to various positions down the intake ducting. Data log it all and then decide where the sensor will end up. I suppose I will have to wait until summer to see how it reacts to high OAT.

Matt,

reviving this thread. I am running a blown application, e85, injecting above the blower only. I was running the IAT below the blower but getting terrible heatsoak so I moved it above the blower. Under normal conditions, does the IAT signal with increasing temp adjust the fuel curve rich or lean? The car starts and idles fine but when the temperature goes up, at part throttle under load it is sluggish.

ed

More temperature reduces air density, reducing the fuel required.

logical pv=nRT....

So now I am suffering from cold sink! Due to adiabatic cooling above the blower (especially with the E85), the IAT is seeing colder temperatures that what would be representative of the charge going into the cylinders. So, should I reduce the IAT correction? Will it accept a negative percent correction in MSII? Thoughts?

ed