Pontiac Fiero 1988 Service Manual page 607

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6E3-A-24 DRIVABILJTY AND EMISSIONS - FUEL INJECTION (PORT)

FUSIBLE LINK

HOT IN CRANK ONLY

COLD START FUEL

INJECTION SWITCH

CLOSED BELOW 3 5 ° C

8 SEC. TIME LIMIT

• B I M E T A L

* 6 S 2 5 4 1 - 6 E

C H A R T A-9

COLD START VALVE TEST

2.8L "P" SERIES (PORT)

Circuit Description:

The cold start valve is used to provide additional fuel during the crank mode to improve cold startups. This

circuit is important when engine coolant temperature is low, because the other injectors are not pulsed "ON"

long enough to provide the needed amount of fuel to start.

The circuit is activated only in the crank mode. The power is supplied directly from the starter solenoid and

is controlled by a cold start switch, which provides a ground path for the valve during cranking when engine

coolant is below 95°F (35°C).

The cold start fuel injection switch contains a bimetal switch, which opens at a specified coolant

temperature. This bimetal is also heated by the winding in the cold start fuel injection switch, which allows the

valve to stay "ON" for 8 seconds at - 2 0 ° C (-5°F) coolant. The time the switch will stay closed varies inversely

with coolant temperature. In other words, as the coolant temperature goes up, the cold start valve "ON" time

Test Description:

Numbers below refer to circled

numbers on the diagnostic chart.

1. Disconnecting the distributor 4-way connector

will disable the other injectors. The amount of

pressure drop depends on the temperature of the

engine. This test could also be performed by

removing the two injector fuses.

2. This test will determine the continuity through

the switch to ground.

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