2001 tacoma mod

Where is the AFM on a 2001 Tacoma 2.4L or is it different on 2001 and on engine. I would like to do the mod that is talked about at the beginning of the forum. The engine is a 2RZ-FE. IS there any other mods to get a little better power out of this slow dog. I put a K&n air filter in but no help.

Welcome to the AF!

The 2RZ-FE uses a MAF meter, not a AFM.

Welcome to the AF!

The 2RZ-FE uses a MAF meter, not a AFM.

Thanks for the reply!
If it uses a Mass Air Flow is there a way to mod. the sensor to give it more horsepower? I have heard of a resistor inline but what wire and how many OHM resistor? Does anyone have a diagram?

I believe you are talking about inserting a resistor into the circuit for the inlet air temperature sensor.

I don't have a reference for that mod handy. You can try inserting a variable resistor into the circuit and seeing what happens at different resistances. Then you can dial in or out any resistance you want with a twist of the dial.

Is the IAT sensor on a 2001 2.4L intergrated with the MAF sensor? There are 5 wires coming out of the MAF and if this is true which two are for the IAT?

The IAT sensor is integrated into the MAF through terminal THA (middle) in the MAF meter connection. E3 is a common with the resistance of the THA-E3 connection increasing with decreasing temperature. The range of resistances is 20 kohms at 0F and .2 kohms at 180F.

What you would have to do is bypass the THA-E3 connection (currently internal to the MAF meter) by cutting the wire connected to the THA terminal in the wiring harness and insert (solder) a variable resistor (0-20 kohms or thereabouts) onto the THA wire before the THA connection on the MAF meter and connect the other side of the resistor to the wire connected to the E3 terminal.

This is my judgement based on the behavior of the MAF meter. If you try it, don't do anything that is irreversible and keep enough wire after you cut the circuit so that you can easily solder the THA circuit back together again.

Before you insert it into the circuit, I would calibrate the resistor to the middle of the range for the values in the pic at the bottom of this post and use them as a baseline for further adjustments. Increasing the resistance should make the mixture richer.

I'm not sure what value this will have. The HO2 sensor will still adjust your mixture to provide the oxygen level in your exhaust that your ECM is calibrated to allow. The above mod will probably only work during open-loop operation. When the engine is hot, feedback to the ECM from the HO2 sensor (and other sensor inputs like the throttle position sensor, etc) determines the mixture and it is considered to be in closed-loop mode. The HO2 sensor feedback should take into account air density (as measured by temperature), which is what you are trying to modify by inserting the resistor.

I guess the bottom line is "try it and see what happens". As long as you can reconnect the THA circuit, no harm, no foul.

http://i16.photobucket.com/albums/b8/rogersb/2RZ-FEMAFMeter.jpg

Thanks for your time in helping with this. I have tried several thing but you nailed it! Works great thanks.

You're welcome

So, does changing the resistance affect your engine when it's at operating temperature or not?

I seem to get a little more power. I set the pot to about 3.6k ohm and the intake temp on the ODB II is 56.6 degrees. I would like to find out how well it works at hot and more humid conditions outside. It was only 45 degrees today so I dont know how much of a difference it made.

By the way on a 2001 2.4L the wires I cut to install the pot was the green and yellow/green wire on the MAF sensor.

If anyone else has any better or more power mods PLEASE let me know.

Thanks again!!

One more thing, if any one has tried this mod and found a better intake temp to set the IAT sensor to please let everyone know.

I thought you would only need to cut one wire (THA) and solder the resistor in between the THA wire and the E3 wire (uncut). The E3 wire is also used by the MAF sensor for airflow measurement.

On my MAF there are 5 wires, 3 go to the MAF and 2 wires are for the IAT. I have taken the Sensor out and ohm'ed the terminals to each lead on the 2 different sensors to find out which wire was which.

I could solder the resistor (pot) in parallel with the sensor. The sensor would still work and adjust the temp then it would just be an additional load the ECU would calulate into the intake temp. I will have to try that.

Again, Im new to all of this and any ideas or comments are welcome.

If you solder the pot in parallel with the IAT sensor, then you may need a pot with a different range than the one matching the resistance of the IAT thermocouple.