Everything I can find tells me that off idle, the IAC does nothing at all. Even if it does... the MAP follows manifold pressure, if you open up another path for air to flow, pressure IS going to change, and the map will see it.

 

Yeah, off idle it should be closed. IAC being used to regulate emissions is pure BS.

 

Thus why I'm discussing out loud with the community.. but that's not what the Mopar guy is telling me that works for dodge; I'm being told the ECM open's closes the IAC to regulate the A/F mix for Emissions; not power or MPG but emissions.. and I can understand what he's talking about because i can feel it.. there are alot of varibles that will cause changes the ECM reacts too.. temps; pressures; so on.. and so forth.. thus the ECM responds by opening closing the IAC to keep that emissions standard.. these motors when producing good power put out high emissions vs some of the newer designs out there.. that's why the 302's and other similar engines where pulled from production because they could not meet EPA emissions.. until they redesigned a lot..

The Map sensor can read the pressure but that does not mean the ECM will respond by adding more fuel to compensate if it's opening the IAC to increase the air more maintain a certain programmed emission output..

I mean dont get me wrong I'm loving the input that's the point of the thread to really think about things through.. I was thinking the same way until this guy really explained all that is going on with in the programming of the ECM.. and how/why it's reacting to different things.. some things just for fuel mix for atomization of the fuel to burn.. but most of what happens is just for the emission output..

From his own words. Sorry if I sound like the crazy uncle.. LOL


But anyways.. so the only couple of things we lack so far from what I'm seeing is as follows

1. Idle will be set; no warm up period so the truck will have to warm a little slower than normal; but if running e-fan that will compensate for it.
2. Slower light off in the CAT.. because lower RPM less output off engine= slower heat up of the
3. engine during hotter temps (less dense air) might not compensate however map sensor might decrease the leanth of the injector pulse thus less fuel to compensate if it can not increase air flow.
(might be a slight problem here) thus why I'm discussing out loud..