Tools:

long flat-head screwdriver, large tip

DMM (Digital Multimeter)

Optional for throttle stop adjustment:

flat-head screwdriver, small tip

8mm socket + ratchet

Labor:

Adjustment of the TPS can reduce hesitation and idle problems.  Checking max resistance of the TPS can also uncover problems with high RPM hesitations.  This resistance method is a more precise method that using the twin diagnostics lights or measuring voltage.  Both inferior methods require you to insert the key into the ignition and turn to the "ON" position; this resistance method does not require you to turn the ignition on.  The double-lights method will not always give you the proper single light on condition.  Voltage adjustments can be skewed from a weak battery. 

To proceed with this procedure, the stock top-mount intercooler needs to be removed via four 12mm bolts - two on each side of the intercooler itself.

	Looking over the driver's side fender into the engine bay - RED arrow showing location of TPS itself.
	Closer look at TPS, with TPS wiring plug unplugged from rest of harness
	Close-up view of TPS plug - note the three wire colors
	DMM probes inserted onto *BACK* (recommended by Mazda service manual) of plug - use GREEN and BLACK wire leads.
	DMM measuring approximately 1k-ohm with throttle at rest/closed. If stock cold start system is still intact, engine must be warmed-up before checking TPS resistance. Next, manipulate the throttle from rest position to WOT - check TPS resistance sweeps smoothly from 1k-ohm to approximately 5k-ohm (+/- 1k-ohm, or between 4k-ohm to 6k-ohm).  Any TPS reading HIGHER than 6k-ohms will need to be replaced soon.  TPS reading over 6.5k-ohms WILL cause high RPM hesitations! There should be NO shorts or "blown opens" (DMM goes out-of-range or infinity) during the transition.
	If idle spec is off, locate adjustment screw. YELLOW arrow points at adjustment screw.
	Use a long, flat-head screwdriver to turn adjustment screw until spec is at 1k-ohm. After adjusting the TPS, you might have to readjust your idle speed via the BAC valve.

For those with no stock cold start system, these next pics show the throttle set-screw, which you can adjust for idle.
Also, for those with no stock BAC valve or BAC valve with idle adjust screw...

	Throttle stop screw - looking from the driver's side fender over the throttle body
	Throttle stop screw - looking from passenger's side fender Note:  loosen the 8mm jam nut, then use a small flat-head screwdriver to adjust.

Questions?  Comments?  Send mail to:  reted@fc3spro.com

02/23/2004