Cold Running Enrichment, Accel. & Starting Hot Engine Info.
COLD RUNNING ENRICHMENT, LAMBDA LOCK
SYSTEM FAILURE SYMPTOMS: Occasional complaint of a brief period of rough idle and power loss during warm up.
TEST
1. Plug in all relays
2. Cold engine, coolant temperature switches closed:
Start the engine, the pulse ratio meter should lock on 60% after three seconds of running until coolant temperature goes above 77~F/ 25~C at which point the pulse ratio meter will oscillate normally.
Hot engine, coolant temperature switches open:
Simulate a cold engine by grounding the WHITE thermal switch lead located at the front of the thermostat housing. Start the engine, the pulse ratio meter should lock on 60%.
3. If inoperative, check:
a. Grounding pin X1 of the decel relay socket should lock the pulse ratio meter at 60% when the engine is running.
b. Pins X1 of the decel relay, 31b of the pulse relay and TKK of the transient enrichment relay sockets should have continuity with the WHITE thermal switch wire.
ENRICHMENT UNDER ACCELERATION DURING WARM UP
SYSTEM FAILURE SYMPTOMS: Hesitation on acceleration for the first few minutes of operation, often accompanied by backfiring into the intake manifold.
TEST
1. Plug in all relays
2. Remove any jumper wires and reconnect thermal and thermo-time switch leads.
3. Bridge the cold start injector plug with a 12v test light.
4. Start the engine and observe both the test light and the pulse ratio meter during the 120 second test period. Results will be one of the following, depending on coolant temperatures.
a. Coolant temperature below 77~F/25~C during the entire test cycle.
Every time the throttle is opened rapidly, the test light should flash briefly. Pulse ratio locked on 60/40.
b. Coolant temperature starts below 77~F/25~C, but goes higher during test.
Test light flashes every time the throttle is opened rapidly until the thermal switch opens, at which point, the pulse ratio meter will swing toward 92% each time the throttle is snapped open for the balance of the 120 second test period.
c. Coolant temperature above 77~F/25~C during the entire test cycle.
The test light will not flash, the pulse ratio meter swings toward 92% each time the throttle is opened rapidly for the 120 second test period.
5. Verify that you no longer get acceleration enrichment through the Lambda system after 120 seconds of operation. The pulse ratio should no longer swing towards 92% after the test period.
6. If inoperative, check:
a. Power to the RED/WHITE and WHITE wires on the vacuum impulse switch.
b. 12v pulse on acceleration at the BROWN wires on the vacuum impulse switch.
c. Pin functions of the transient enrichment relay as given at the end of the cold start test procedure.
STARTING, HOT ENGINE
SYSTEM FAILURE SYMPTOMS: Prolonged cranking to restart a hot engine.
NOTE: All normal C.I.S. pressure checks must also be carried out.
TEST
1. Disable the ignition system by disconnecting the primary circuit plug from the distributor.
2. Unplug:
a. Fuel pump relay
b. Thermo-time switch on the intake manifold
3. Connect a test light from 12v to the GREEN and WHITE wires at the cold start injector plug.
4. Engage the starter. The test light should begin to pulse after approximately two seconds of cranking.
5. If inoperative, check at the pulse relay socket:
Pin 50 12v when cranking
31 Ground at all times
31B Continuity with the GREEN and WHITE wires at the cold
start injector plug