an Ideal IAT temperature...

[navyblue2000]

Don't lock this on me, please. I got to thinking about a few things this weekend at SLP day. I was autotapping some logs, did the 4.7k Ohm resistor, it read right at 57*. well, i took it out and left the sensor open, it read -38*. might it run a little rich? start it up, rev it...yeah. rich. I know timing advance can be touchy, as far as knock and detonation goes.
I guess I'm a little confused. telling the car the air is colder advances timing, how, and why?
now once that gets out of the way, it seems like an ideal operating IAT should be found for optimum spark advance? maybe one that would advance 4 or 5 degrees of timing, just throw 100 octane in to kill knock? or does it not work that way?
That being the case, it seems like optimum temps could be found, and resistors could be fabricated to use like rev limiter pills...depending on the advancec you wanted, just put the resistor in.

[Magnus]

IAT plays a VERY small role in timing advance.

There are Tables in the PCM.. that measure the temperatures and load and determine how much timing advance to give you..

The real big one is engine coolant temp (ECT). That one plays the biggest role in timing advance I think.

Keep your ECT down and you'll get more timing advance.

I did a study a while back, maybe a year or so ago.. made many logs, graphs with excel, the works.. it was VERY clear that 160 ECT gave MUCH more timing advance than 210 ECT.

As ECT goes up, TA goes down.

IAT tricker has so little of an affect (if any) that I removed my resistor long time ago.

[navyblue2000]

Thanks for the info keith. Where exactly is the ECT located on the car?

[Magnus]

Under the throttle body. It goes into the lower intake manifold.. 3 wires go to it believe. The wires run along the TB, through a loop thats bolted to the side of the TB and to the sensor.

You can see it in this picture sticking out of the lower intake

[pgriffith]

I dont know what the ideal temp is but I always throw a code that says Air intake temp too high. I cant seem to shake it.

[navyblue2000]

here we go...
i don't know how resistor math works...
but with 3 4.7kohm resisitors in the coolant temp spot, it reads exactly 100*. now. if we can find a good mix of false IAT's and ECT's, we might be in business somewhere, is that corret?