After-start, Warm-up and Cold Acceleration Enrichment
To ensure smooth running, the system supplies additional fuel to a cold engine by increasing differential pressure regulator current for a short period after starting and during warm-up. The coolant temperature sensor provides the control unit with temperature input. To ensure good throttle response when the engine is cold, the system also briefly delivers additional fuel when the throttle valve is opened suddenly.
To test:
| 1. | Disconnect oxygen sensor harness connector (four-terminal connector on right engine mount). |
| 3. | Disconnect the harness connector from the coolant temperature sensor. See Fig. 6-44. Connect a 2500 ohm resistance across the connector terminals to simulate a cold engine signal. |
| 4. | Start the engine and let it idle. |
| Fig. 6-44. | Location of coolant temperature sensor on 2.0 liter 16-valve Motronic engines. |
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NOTE-
Differential pressure regulator current should adjust to between 10 and 25 mA for approximately 6 to 9 seconds, then gradually drop to between 5 and 15 mA.
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| 5. | Open the throttle completely, then let it close. |
NOTE-
Differential pressure regulator current should increase briefly, indicating cold acceleration enrichment.
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