IAT/ECT Installation - Version 1 (Pots Mod)

IAT/ECT Installation

Supplies needed:

  • 1 roll 18 gauge wire or larger
  • 2 potentiometers, .5 watt, 0-50k ohm resistance
  • soldering iron and solder
  • wire cutting/splicing tool
  • 4 crimp connectors (18-22 gauge)
  • 1 roll electrical tape
  • 2 knobs

Which wires to tap for ECT?
The Electronic Coolant Temperature sender is located at the back (drivers side) of the motor, on the top of the cylinder head water outlet (black phenolic plastic block), where the top radiator hose connects to the motor.

Pick either one of the two wires to cut.

Splice the 18 gauge wire onto each end that was cut

Run the wire to where you are going to mount the control knobs. I put mine in the door pull trim on the drivers door… looks tight and is easy to access.

Solder the wires, 1 to the center terminal, 1 to the outside terminal. The third terminal remains unused.

Now you’re ready to try… set knob to zero resistance and start car. Turn up the ECT knob until you see the idle jump to about 1300-1400 rpm. This mod really comes alive after 4500 rpm. If you notice pinging, try either a higher octane gas, or reduce the amount of turn to the ECT knob until the pinging stops.

As far as IAT mod, for 98’s follow the Keman mod instructions (Flints FAQ’s), except put the wires and pot in place of the resistor. For 99’s the wire you need is on the main MAF harness, the white/green wire at the outer end of the 6 wire harness. Everything else is the same install as the ECT mod above. Best setting is 37-38k ohms for the IAT pot (approx 200 degree crank of the knob).


  1. Turn up knobs only when you need it. Cranking the knobs all the time may cause the computer to start “adjusting” the resistance out, and starting the car hot with the knobs cranked could cause flooding or plug fouling.

  2. The ECT knob when on, turns off the cooling fan, so overheating is a possibility if you don’t watch the gauge. This is not a problem if your moving above 30mph, but idling a long time may be a problem. Turning the AC on will activate the fan, so if you choose to drive stop and go for more than 5 minutes with the ECT knob cranked, keep that AC on.


Knob mounting in door… wires run thru door into the rubber tube containing the speaker wires, then a cut is made to the back of the rubber tube to allow the wires to run into the front fender, and to the engine compartment.

Location of IAT (1999-2001) and ECT (all) sensors:

Routing of wires from under hood to door panel:

Dyno Results (gains on the dyno showed a peak gain of 5.4 hp / 7.7 tq, and a max gain of 14.4 hp / 10.8 tq. at 6500 rpm. 1999 s/r with a K&N filter and udp added.)