TPS Adjustment

Signs & Symptoms:
1. The engine's running too rich,
2. Your car won't pass SMOG because it's too rich/lean,
3. The idle keeps hopping between fuel-cut and fuel-return, or
4. The engine seems sluggish at certain points.

Diagnosis: The TPS needs to be adjusted. The ECU may be fooled into thinking that the throttle's opened even though the engine's only idling. Result... The engine's getting too much fuel. Conversely, the throttle can be really open, but, the ECU thinks that the engine's still idling. Thus, the engine's not getting enough fuel AND the ECU isn't "seeing" full throttle situations.

Tools Needed:
1. Feeler gauge (look for sizes in Procedure),
2. Digital Multimeter with small, sharp test leads, and
3. Phillips screwdriver.

TPS Terminal Identification; from top to bottom with the terminals facing downstream of the intake:
1. E2: ground
2. IDL: idle switch
3. VTA: Resistor (increased throttle opening = increased resistance)
4. Vcc: +12V

Procedure:
1. Disconnect TPS wire connector,
2. Use table below and insert the proper feeler gauge thickness between the screw stop and throttle pulley,
3. Connect test leads to IDL and E2 terminals,
4. Use table below to see if IDL-E2 resistance within spec,
5. If not, loosen the 2 screws holding the TPS to the T/B,
6. Insert a 0.47 mm (0.0185") feeler gauge,
7. Gradually turn TPS clockwise until the meter "deflects,"
8. Recheck spec using values for IDL-E2 in table below,
9. Make sure that the 2 screws are tight enough, and
10. Connect TPS wire connector.