Federal
Making these checks and adjustments together is very important to both driveablity and emissions control. If the equipment necessary to accurately perform this work is not available, we suggest turning the job over to a local repair shop that has the needed test equipment. In a properly equipped shop, these checks and adjustments can be made quickly, accurately, and at resonable cost.TEST AND ADJUSTMENT CONDITIONS
1. Engine oil temperature must be at least 176° F (80° C) and radiator cooling fan has operated at least once.
2. All electrical consumers switched OFF (radiator cooling fan must not be running during checking or adjusting).
3. A/C switched OFF.
4. Throttle switches adjusted and functioning properly. For more information refer to COMPUTERIZED ENGINE CONTROLS
5. The exhaust system must be free of leaks.
6. There must be no engine vacuum leaks.
7. The oxygen sensor must be connected and operating properly. For more information refer to COMPUTERIZED ENGINE CONTROLS
8. Throttle cable adjustment must be OK.
9. Idle stabilizer valve must vibrate and hum with the ignition switch turned ON.
10. Coolant temperature sensor (blue) must be OK.
TEST AND ADJUSTMENT SET-UP
1. Put vehicle in PARK or NEUTRAL set parking brake.
2. Turn ignition switch OFF.
Tester VAG 1367 Hookup:
3. Connect VAG 1367 engine tester using VAG 1367/8 inductive pickup, or a suitable strobe timing light and tachometer may be used.
4. Remove the cap from the CO tap tube that comes from the exhaust manifold and connect an EPA approved CO tester to the CO tap tube using VW special tool #6006-0019 high temperature silicone connecting hose, (or equivalent).
NOTE: Non-approved connecting hoses may dramatically alter your readings. Adaptor must be connected tightly to CO tap tube to prevent measuring errors.
TEST AND ADJUSTMENT PROCEDURES
CAUTIONS: DO NOT reconnect coolant temperature sensor while radiator cooling fan is running Digifant control unit damage may result.
DO NOT START engine with coolant temperature sensor disconnected. The control unit will go into open loop making accurate adjustment impossible.
Be certain that TDC sensor is properly seated in recess on flywheel housing (if used).
IGNITION TIMING
1. START engine and let idle.
Coolant Temperature Sensor:
2. Disconnect harness connector from the blue coolant temperature sensor.
3. Raise engine RPM to between 2000 and 2500 RPM and check ignition timing, checking value is:
4° to 8° BTDC at 2250 ± 50 RPM
4. Adjust ignition timing if needed.
5. Loosen distributor and rotate until specification is correct, adjusting value is:
6° ± 1° BTDC at 2250 ± 50 RPM
6. Tighten distributor bolts to specification.
7. Reconnect blue coolant temperature sensor harness connector.
8. Turn ignition switch OFF.
TIMING ADVANCE CHECK
1. START engine and let idle.
2. Disconnect blue coolant temperature sensor harness connector.
3. Check and record ignition timing at 2500 RPM.
4. Reconnect blue coolant temperature sensor harness connector with engine running.
5. Once again check and record ignition timing at 2500 RPM.
6. Timing must be:
value recorded in step 3 plus 20° to 30° additional advance
7. If value recorded in step 5 is the same as value recorded in step 3, check for open circuit in coolant temperature sensor wiring or faulty coolant temperature sensor.
8. If the coolant temperature sensor and wiring are found to be OK, Digifant control unit is faulty and should be replaced.
IDLE SPEED AND CO CONTENT
1. Disconnect crankcase ventilation hose from emission control valve and route the hose such that only fresh air is drawn in.
2. START engine and let idle. Engine will run from 1 to 4 minutes at increased RPM.
3. Once idle speed has reduced and stabilized, disconnect harness connector from blue coolant temperature sensor while engine is idling.
4. Momentarily raise engine speed to over 3000 RPM 3 times then let idle.
5. Check CO content and idle speed, they must be:
750 to 850 RPM
0.3% to 1.1% CO content
NOTE: If engine is not within the above specifications, continue with procedure below. If engine is within specifications, no further adjustments are necessary however, you must complete this procedure go to step 10.
6. Adjust by alternately turning adjustment screws (arrows) until both specifications are obtained.
7. Re-connect coolant temperature sensor.
8. Momentarily raise engine speed to over 3000 RPM 3 times then let idle as before.
9. Check CO content it must be:
0.3% to 1.1% CO content
10. Turn ignition switch OFF.
11. Re-connect crankcase ventilation hose and coolant temperature sensor.