TOYOTA PREVIA 91-97 REPAIR MANUAL

4-26 DRIVEABILITY AND EMISSIONS CONTROLS

Air Cleaner Cap

MAP Meter

Fig. 78 View of the Mass Airflow Meter and surrounding compo-

nents—2TZ-FZE engine

8. Installation is the reverse order of removal. Tighten the meteri|screws
   to 61 inch Ibs. (7 Nm).

Throttle Position Sensor

OPERATION

To reduce HC and CO emissions, the Throttle Positioner (TP) openfi the
throttle valve to slightly more than the idle position when decelerating. This
keeps the air/fuel ratio from becoming excessively rich when the throttle valve
is quickly closed. In addition, the TP is used to increase idle rpm whef| power
steering fluid pressure exceeds a calibrated value and/or when a largellectrical
load is placed on the electrical system (headlights, rear defogger etc).

TESTING

1991-94 2TZ-FE Engine

I See Figures 79, 80, 81 and 82

1. To check the resistance between the terminals of the throttle
   sensor, unplug the wiring from the unit.

Thickness Gauge.

E2

Ohmnneter

Fig. 79 Insert a thickness gauge between the throttle stop ;

and stop lever to check the throttle position sensor—2T2-F ;

engine

90914GG8

crew

•VC

-VTA

IDL

E2

Fig. 80 Throttle position sensor terminal locations—2TZ-FE

engine

Clearance between

lever and stop screw

0 mm (0 in)

0.60 mm (0.0398 in.)

1.05 mm (0.0413 in.)

Throttle valve

fully opened

Between

terminals

VTA - E2

IDL-E2

IDL-E2

VTA - E2

VC-E2

Resistance

0.3 - 6.3 kn

2.3 kU or less

infinity

3.5 - 10.3 kn

4.25 - 8.25 kn

9091 4G70

Fig. 81 Throttle position sensor resistance values — 1991-93

models

Clearance between

lever and stop screw

0 mm (0 in.}

0.60 mm (0.0398 in.)

1.05 mm (0.0413 in.)

Throttle valve fully

open

Between terminals

VTA - E2

IDL - E2

IDL - E2

VTA - E2

VC - E2

Resistance

0.47 - 6.1 kO

2.3 kQ or less

Infinity

3.1 - 12.1 kO

3.9 - 9.0 kO

90914G71

Fig. 82 Throttle position sensor resistance values — 1994 mod-

els