IAT Timing Tricker

Tools & parts you will need:
4.7k ohm, 1/2 watt resistor
  • Plastic zip tie
  • electrical tape*
  • plastic grocery bag*
  • Expect approximately 5 minute – 20 minute install time.
    *These are optional items.
    Date:  July12, 2000
    Car:  1999 Z28 Camaro, At the drag strip
    Installers:  Eric and Kelly Barger
    Email:  help@installuniversity.com
    People who helped us from major tech talk to general advice:
    When purchasing, viewing, using, and/or any other method applied to this publication you agree to the following statements.  You, your next of kin, heirs or assigns release www.installuniversity.com, all other persons associated in the making, production, participation, and sale of this publication.  Rephrased in plain English:  When you purchase this CD, book, or view this web page you, your next of kin, heirs or assigns agree not to sue any associated persons with the publication for any accident or damage in ANY form (mental or physical to your car and/or yourself) because of this publication or your failure to heed proper safety, maintenance and/or modification procedures.  You also agree that your next of kin, heirs or assigns cannot sue all persons associated in the making, production, participation, and sale of this publication.  
    Perform all these installs at your own risk.  Know how to use all of your shop equipment and take necessary safety precautions when performing ANY modifications and or maintenance items to your vehicle.  Seek the advice of a paid professional and do not substitute this publication for the advice of a paid professional.  This product is how we accomplished our installs and is not meant to be carved in stone.  We are not responsible for a mistake, misprint, or any other error found in this guide.  This guide is intended as a supplement and not to be your only source of information.
    Purpose:   Will increase your timing which will help improve your drag strip time. This mod has been shown to increase timing by as much as 1.5 degree's.  This modification is NOT suggested to do if you have knock retard or detonation.  When you are in an environment where the intake air temperature is below 57 °F this modification will not benefit your cars performance.  These conditions will hurt performance instead of improving it.  
    Preface:  Before you start into this install be sure you know how to use all of your shop equipment.  Take your time and be careful.
    Reminder:  Make sure you have the keys out of the ignition.  Why?  When you remove the sensor from the air box lid assembly and throttle body you do not want to start the car.  You will set the Service Engine Soon (SES) light if you do start the car with the sensors removed.  You can easily reset the SES light by following these steps:
    1.  Turn key to the "on" position but don't start car 2.  Pull the PCM BAT and PCM IGN fuses in engine compartment 3.  Wait approximately 5 minutes 4.  Turn ignition off 5.  Replace fuses 6.  Start the car and the make sure the light has went off
    1.  Make sure your car is NOT running.  Open the hood of your car and look in the front and center of the engine compartment.  Locate the intake-air-temperature (IAT) sensor wire harness (see blue arrow in Figure 1)
    Figure 1
    2.  Disconnect the wire harness from the IAT sensor (see Figure 2).  Gently pull the tab out and lift the sensor out of the housing.  
    Figure 2
    3.  Take your resistor and shape it in the form of the letter "U" (see Figure 3).
    Figure 3
    4.  Locate the tiny receptacles located in the IAT wire harness (see blue arrows in Figure 4).
    Figure 4
    5.  Place one end of the resistor into one slot on the intake air temperature (IAT) wire harness receptacle (see Figure 5).  The receptacles are metal and appear sliver in Figure 5 below.  Do the same with the other end of the resistor and place it into the other IAT wire harness receptacle.  The resistor will get deformed and probably appear squished.  This is ok and not a problem.
    Figure 5
    6.  Bend the resistor over then against the wire harness as shown in Figure 6.
    Figure 6
    7.  If you plan on leaving this modification on your car when you drive around town, now is a good time to seal up the IAT wire harness (that has your resistor) and the IAT sensor (on the air box lid) using a small piece of a plastic grocery bag and electrical tape.  If you plan to run this modification at the drag strip only than you will be just fine leaving everything the way it is right now.  You might want to tape the resistor down to be sure it does not fall out.  We have never had any problems with it falling out.  Of course, there is always a first time and the drag strip is the last place you want to see the service engine soon (SES) light come on.
    8.  You want to make sure that the wire does not fall down and get caught up in your belt or pulley's.  We suggest using a plastic zip tie to hold the wire up.  We tied ours down through the tab on the wire harness and around the IAT sensor housing (see Figure 7).  Obviously we do not have the ends sealed up.  This is because we run this modification that the track only. 
    Figure 7
    Comments:  This modification is always a subject for a good debate.  We verified using Auto Tap that the resistor makes the PCM think the car is taking in air with a temperature of 57 °F.  We have no Auto Tap data to support the claim that timing is increased as much as 1.5 degrees.  Those figures are based on the claims of many people who use this modification at the track.