Best place to put my IAT Idle air control sensor Intake or Intake manifold? resistor
 

I have a 95 jeep cherokee 4.0 6cyl for best MPG results should i put it in my warm air intake off of the exhuast header or put it back in the intake manifold where it came from the factory.

not sure if youve seen the intake on a 4.0 but it is right above the header and gets almost as hot as the header. right now i installed the sensor in the custom 3 inch wai intake off the header.

Also what would it do to add one of those resistors to that sensor too, i see those all over ebay for 20.00

Adding a resistor may temporarily change your a/f ratio, but eventually the computer will figure out the new baseline from the o2 sensor readings and you'll be back where you started.

-Jay

yea i got ya the ecu is smart.

as for that i do have an efie installed on the 02 and map sensor to lean it out with the extra hho being added.

You want the IAT as close as possible to the combustion chamber w/out encountering heat soak. Most OEM's put it in the plastic intake just before the throttle body, but I have seen some that install it directly into an intake manifold runner.

If you have some method of leaning out the fuel manually then you do not want to put a resistor on any of your sensors.

well thats what i thought too getting it away from heat would be better for mpg. i dont have a resistor on the iat now i am just using the efie to lean the jeep out.

stock the sensor is on the intake manifold and gets just as hot as the exhuast header so i pulled it, plugged the intake runner hole and put it in the warm air intake tube. bunged it in there and made the harness longer so it would work and its a new sensor too.

so in the end leave it in the cooler intake not the hot intake runner correct

the reason you see those resistors all over ebay for $20 a piece is because you can get a dozen (or so) from radioshack for about a dollar or two. this is making somebody some money and not because of fuel saved either.

I would say to work on your WAI as far as monitoring the temps there and possibly increasing the temps if possible. the resistor won't do much because of reasons stated earlier. if the air is actually warmer, then you will see a difference. I noticed you already had a WAI. it took me a while to get mine dialed in to the right temp. I need to work on it again as colder temps are bringing my intake temps down.