Ok let me try again to see if I can find an answer to a question that I have been unable to find an answer for a long time.

You all probably know that the IAT usually reads way higher that the actual ambient temperature, mostly because its located on the IM and the metal-to-metal contact readily conducts heat to the iat sensor.

I can understand that the "real" air temperature of the air entering the cylinder might be a little bit higher than the ambient temperature but a difference of 30° to 40°F ??
The PCM uses the iat to determine a lot of stuff (timing, fuel trim..). So if the PCM is getting the wrong information its making the wrong decisions, UNLESS the IAT reading is already compensated for that 'false' increase in temperature. i.e. the pcm knows that when the iat is reading 110°F it is actually 70°F and treats it as 70°.

Is that the case ? or not ? anyone knows what is really happening here ?

 

There is a nice thread about that on pgmfi.org.

In my opinion, having the iat sensor closer to the head combined a thermal gasket will result in minimal error. Remember, that sensor doesn't make huge adjustments in timing and fuel. I'm not disagreeing with you. I believe there is some heatsoak.

 

Thanks for your reply. I will try to lookup that thread on pgmfi.

By thermal gasket you mean a gasket between the block and the IM, right ?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AnAccordIsForever &raquo;</TD></TR><TR><TD CLASS="quote">
By thermal gasket you mean a gasket between the block and the IM, right ? </TD></TR></TABLE>

Correct.

To save time:
http://forum.pgmfi.org/viewtop...t=iat

There was some info in there also that talks about the code difference between the p30 and p72 in regards to the iat compensation.

 

or you can just put it in your intake pipe; youll have to retune iat multipliers; but it will be smoother overall.

yeah p72 code is way better than p30 in that matter; iat's got load based correction (low/med/high) as where p30 only got just 1 temperature based multiplier

 

well, p30 and p72 are third party ecu's, and that too OBD1, right ?
I don't really intend to swap the ecu at this point. I just want to know what the 'stock' ecu is doing with the iat.

The plan, so far only on paper, is to leave the original IAT in the plenum/im, build an 'extension cable' to run from the original iat connector to somewhere near the filter of the cai and just mount the new iat sensor in that area somehow. Doesn't have to be on the pipe or tube. I dont want to drill in the intake tube/pipe and leave room for leakage.

 

see if you do that with a stock ecu it will throw iat multipliers off

 

Hi

First, I am not honda mechanic so not familiar with them but if your map sensor is reading from same place in the IM, moving the air sensor may mess ECU up as its bases pressure at a air temp to get fuel/ignition timing.
I would first check to see if sensor is truly heat soaked by measure incoming air temp in manifold (you can pull small vacuum hose and measure with fluke meter the temp.
If its way off then insulation gasket mentioned is probably best bet.
or you could try an insulate sensor but if it was designed like that you might be stuck if using stock ECU.
Newer versions of K24 now use plastic IM, probably to keep cool air and weight/price down.