I bought my car and it already had the 1le elbow,and i guess a resistor put on the IAT sensor,so the hole on the elbow was plugged off,is this normally done?? my car has a pcmforless.com tune so im wondering if it would throw off my tune,anyone have any help? should I try to find the sensor and plug it in or leave it the way it is now?

 

if you don't have any knock retard, leave it. All that resistor mod does is tells the PCM that it's a constant cooler temp.

If you have detonation or the computer is pulling timing, then you might have a problem. If you don't, leave it it's fine.

 

the car seems to run fine,no codes have ever popped up, i just noticed this when I had to replace my elbow the other day,wasnt sure if it was a big deal or not

 

I'd throw a sensor in there. It's there for a reason. I don't think your really seeing any performance gain. The PCM reading a cooler temp is just throwing more fuel in there.

 

IMO the IAT resistor is good for a 1/4 mile run or w/e but not for daily driving.

 

I don't think there are any significant gains with that. Put the sensor back in.

 

I seen a dyno before with it and I believe there was a 5-6 RWHP gain. Just as much as I seen with a bunch of other mods that people spend a 100+ $ on. But this one only costs a few cents.

 

That resistor trick (4.7k or 5.2k) has been tested and I wish I would have kept the link. I did this resistor thing at the track just in case it had any value. At 4.7k resistance the PCM is being told the outside air temperature is 50 something degrees. This will richen the mixture if the ambient air temperature is greater and lean it if lower. I would imagine spark advance is affected as well.

Anyway, from memory the dyno results were not favorable to the resistor trick. Although it doesn't seem like it should go this way, the engine picked up some knock with the trick and power fell because of it. I probably shouldn't comment without hard proof but that resistor thing is pretty insignificant. Personally I would re-install the sensor if you can still do it.

 

I don't know why you'd want to "trick" the PCM into thinking that the ambient air temp was much lower than in reality. Modern cars run so well due to the fact that they have all these sensors, allowing the PCMs to fine-tune running parameters over the whole range of weather conditions. If your car is tuned properly, the IAT resistor will not give you any performance gain. It will trick the PCM into advancing the timing, which will cause knock, which will cause knock retard, which will decrease performance - assuming you have a good tune.

 

Did anyone who responded notice the person who asked the question has a speed-density 1993. That's the last setup you want to put a resistor in. The ECM needs the exact inlet air temperature to calculate the density of the air, so it can calculate the mass flow of the air, so it can calculate the fuel flow. Setting the IAT at a fixed temperature will really screw things up.

Its not the same as the 94+ MAF cars, where the IAT is used for little more than a possible 3* timing offset for very high inlet air temps.

 

thanks for the help guys,ill have the resistor removed and get the sensor installed,the car does seem to run rich and smoke a bit when I get on it,someone else told me this could be do to that resistor

 

I can see how it would be more important for a speed density car... but if it seems to run good.

 

[QUOTE=ZRedLT1
I can see how it would be more important for a speed density car... but if it seems to run good. [/QUOTE]

I'm not a fan of the highly reliable butt meter

 

Once the cars been tuned no need for "backyard' modes like that. The best thing you can do is relocate the IAT to a cooler part of the Intake system were it wont get heat soaked and can get a more accurate reading.

 

[QUOTE=Injuneer]Did anyone who responded notice the person who asked the question has a speed-density 1993. That's the last setup you want to put a resistor in. The ECM needs the exact inlet air temperature to calculate the density of the air, so it can calculate the mass flow of the air, so it can calculate the fuel flow. Setting the IAT at a fixed temperature will really screw things up.
QUOTE]

my thoughts exactly on that one. even with the tune, an IAT on a speed density car is crucial