The stock position of the IAT sensor (in the rubber intake elbow just before the throttle body) causes it to pick up a lot of intake manifold heat. This can be an extra 10 degrees F at highway speeds and 30 degrees F (or more) at idle. This causes the computer to retard the timing (zapping power) and causes the engine to run overly rich (since the MAF thinks there's more air going through it than there really is due to artificially high temperatures). By moving the IAT towards the air filter (away from the hot manifold), the ECM will get a more accurate reading of the actual intake temperature and will properly adjust the timing and fuel/air ratio. There's no need to worry about the air heating up more as it passes beyond the new location of the IAT since at wide open throttle, it takes the air 1/1000 of a second to travel from the air filter into the engine.
First, remove the IAT sensor from the bend in the rubber intake elbow. Then plug up the hole on the elbow with something. The site you relocate the IAT to will depend on what air intake (stock or after-market) you have. You want it as close to (if not, right in) the air filter. Snip the sensor wires first, as you can splice in lengths of wire after the sensor is in its new location. On a stock air box, you can drill a hole into the back of the box. On after-market intakes, try drilling a hole at the bottom of the air filter itself (works best on K+N conical filters) or on the pipe/tube to which the filter is connected. Either way, make sure the hole is placed in location which sees the air AFTER it passes through the air filter (otherwise debris may ruin the sensor). Then, insert the sensor into the hole. After that, just splice wires to reconnect the sensor, solder the connections and protect with electrical tape or heat shrink-wrap.

 

My cars been like that for 5 years now so it's kind of old news. But nice post

-Shannon

 

Would this really make any difference or should I not even bother?

 

I would also like to know the answer to this question? Thanks

 

IMO its a waste of time, dont bother.

 

FYI the PCM adjusts timing and fueling based on the COOLANT temp not the AIR temp... so moving the IAT will not change anything. Also, the MAF doesnt use IAT readings either... it measures air directly w/o the help of other sensors. Now if you were to say moving it would help speed density people then Id agree with you.

 

I can't say I have ever seen the value of this "mod" either. I've never seen anything in the PCM tables referring to timing vs. IAT.

 

Ive heard of gas mileage improvements from unplugging the iat, is this possible/worth trying?

 

all that will get you is a check engine light

 

I've never seen a table for the IAT in the PCM either, I don't know why it's even there. Maybe there's a "hidden" table for it, dunno.

If you want to read it lower, just simply unpug the sensor!
I don't know how many of you know this, but it will report -40F to the PCM if its unplugged! That's pretty "cool", so if it has any effect on timing, it should show up on the logs. Go play with it I never had the time to fiddle with it...
Good luck!

 

Nope, no SES light, at least not on my '94 OBDI.

 

The people most in favor of this mod are the ones trying to get you to pay $40 for $2 worth of parts for a kit, and they guys looking for the cheap and easy solution to modifying the ever hard to work with computer controled cars(note sarcasim here). Then again once they begin to learn anything about these cars they find out reprogramming the pcm is cheap and much more effective than screwing around with the sensors that feed it info.

 

yeah, i did it years ago and it is a waste of time. Nothing changed.

 

yeah, but he has a 97 (OBD2)

 

There has been alot about what the IAT does not impact, what does it impact and what is its purpose. 96 Caprice has great point.