What is the specified T.O.C.S. operating pressure at sea level?

At 0 m (0 ft), sea level, with atmospheric pressure of 101.3 kPa (760 mmHg, 29.92 inHg), the specified operating pressure is −73.3±0.7 kPa (−550±5 mmHg, −21.65±0.20 inHg).

Which way do I turn the adjusting nut if T.O.C.S. pressure is lower than specified?

Turn the adjusting nut clockwise until correct adjustment is made. If pressure is higher than specified, turn it counterclockwise.

What precaution should be taken when adjusting the T.O.C.S.?

Turn the adjusting nut in or out with the lock spring in place, and always set the lock spring properly to prevent changes in set pressure.

How does altitude affect T.O.C.S. operating pressure?

Operating pressure varies in proportion to altitude. For example, at 1,000 m (3,280 ft) above sea level, the T.O.C.S. operates at −63.3 kPa (−475 mmHg, −18.70 inHg) instead of the sea-level value.

What does manifold vacuum do during the T.O.C.S. check?

Manifold vacuum pressure increases abruptly to −80.0 kPa (−600 mmHg, −23.62 inHg) or above and then decreases to the level set at idling.

Home/ Registry/ Nissan/ Micra/ 1990 Nissan Micra/ Photo supermotors.net/registry/media/210310

Nissan Micra T.O.C.S. Throttle Opener Adjustment - Emission Control EF & EC-30

T.O.C.S. operating-pressure adjustment with negative-pressure spec, Nissan EF & EC manual

‹ ›

TOCS operating-pressure adjustment: specified pressure at sea level is -73.3 +/-0.7 kPa (-550 +/-5 mmHg, -21.65 +/-0.20 inHg); manifold vacuum spikes to 80 kPa during decel.

AI caption June 2005 · Photo 130 of 412

This is page EF & EC-30 from a Nissan service manual section on Exhaust Emission Control, specifically the Inspection and Adjustment procedure for the Throttle Opener Control System (T.O.C.S.). The page continues a step-by-step check: step 5 notes manifold vacuum pressure abruptly increasing to −80.0 kPa (−600 mmHg, −23.62 inHg) or above before decreasing to the idling level, illustrated by a negative-pressure-versus-time graph (figure EC502) labeling maximum negative pressure, operating pressure, and idling pressure. Step 6 gives the specified T.O.C.S. operating pressure at sea level (101.3 kPa / 760 mmHg / 29.92 inHg atmospheric): −73.3±0.7 kPa (−550±5 mmHg, −21.65±0.20 inHg). Step 7 explains adjustment: turn the adjusting nut clockwise if pressure is lower than specified, counterclockwise if higher, and cautions to keep the lock spring in place during adjustment to prevent changes in set pressure. Illustrations show the adjusting nut on the engine and a cross-section of the T.O.C.S. valve with the adjusting nut and lock spring. A right-column note explains that operating pressure varies with altitude and how to determine correct operating pressure from atmospheric pressure or elevation, with an example: at 1,000 m (3,280 ft) elevation the T.O.C.S. operates at −63.3 kPa (−475 mmHg, −18.70 inHg).

Is this accurate? Sign in to help verify it.

Frequently asked questions

What is the specified T.O.C.S. operating pressure at sea level?: At 0 m (0 ft), sea level, with atmospheric pressure of 101.3 kPa (760 mmHg, 29.92 inHg), the specified operating pressure is −73.3±0.7 kPa (−550±5 mmHg, −21.65±0.20 inHg).
Which way do I turn the adjusting nut if T.O.C.S. pressure is lower than specified?: Turn the adjusting nut clockwise until correct adjustment is made. If pressure is higher than specified, turn it counterclockwise.
What precaution should be taken when adjusting the T.O.C.S.?: Turn the adjusting nut in or out with the lock spring in place, and always set the lock spring properly to prevent changes in set pressure.
How does altitude affect T.O.C.S. operating pressure?: Operating pressure varies in proportion to altitude. For example, at 1,000 m (3,280 ft) above sea level, the T.O.C.S. operates at −63.3 kPa (−475 mmHg, −18.70 inHg) instead of the sea-level value.
What does manifold vacuum do during the T.O.C.S. check?: Manifold vacuum pressure increases abruptly to −80.0 kPa (−600 mmHg, −23.62 inHg) or above and then decreases to the level set at idling.