Check / Adjust Timing, Idle Speed and CO% on Cars Without Oxygen Sensor
Timing:
- Engine at operating temperature
- Radiator fan should have cycled at least once
- All electrical accessories OFF
- Check timing at idle speed*
- 3* ATDC
NOTE: *ldle speed must be correct before adjusting timing
Idle Speed:
- Engine at operating temperature
- Radiator fan should have cycled at least once
- Turn headlights on high beams to load the engine through the alternator
- Turn idle speed screw until correct idle speed is obtained
- 850-1000 RPM
CO%:
The CO% can be adjusted by turning the adjustment screw on the air sensor lever.
- Connect CO% tester
- Insert tool P377 or 3mm alien wrench
- Turn adjustment screw until correct CO% is obtained. (See engine
compartment for sticker or pages 19 and 20 for specifications) - Remove adjusting tool after each adjustment
- Accelerate engine briefly before reading the CO% value
Check / Adjust Timing, Idle Speed and CO% on Cars With Oxygen Sensor
Timing:
- Warm-up engine
- Radiator fan should have cycled at least once
- All electrical accessories OFF
- Cars with stabilizer – BYPASS stabilizer
- Check timing at idle speed (idle speed must be correct before adjusting timing)
- Audi 5000 Turbo = 21° BTDC@3000 RPM
- 1979 Audi 5000 Calif. w/auto = 6° BTDC @ idle
- 1982 Audi Calif. w/man. trans, All 1983 Audi & VW w/man. trans = 6° BTDC @ idle
- All other VW and Audi = 3° ATDC @ idle
Idle Speed:
- Warm-up engine
- Radiator fan should have cycled at least once
- All electrical accessories OFF
- Cars with stabilizer – BYPASS stabilizer
- Turn idle speed screw to correct idle speed
- Idle speed specifications on pages 19 and 20 or engine compartment sticker.
CO%:
Connect VAG 1367, Siemens 451 or equivalent:
VAG 1367:
- Connect red (+) lead to battery
- Connect black (-) lead to ground
- Connect green (dwell) lead to the blue/brown or blue/white wire at the oxygen sensor test connection using adaptor US 1112
- Set to 4 cylinder operation
Siemens 451:
- Connect red (+) lead to battery
- Connect black (-) lead to ground
- Connect blue (dwell) lead to the blue/brown or blue/white wire at the oxygen sensor test connection using adaptor US 1112
- Set to 4 cylinder operation
NOTE: Only connect the f+J and (-) and (dwell) leads of VW 1367 and Siemens 451. If other test leads are connected the “duty cycle” readings will be inaccurate. Tester must be set to 4 cylinder operation.
Remove Crankcase Breather Hose(s):
- Remove crankcase breather hose(s) from valve cover
- 5 cylinder cars – plug hose
- 4 cylinder cars – do not plug hose
Disconnect Charcoal Canister Purge Hose:
1982 and earlier VW’s
- Pull the charcoal canister purge hose out from the front apron
- Not applicable on Dasher, Quantum, 1982 Scirocco
- Not applicable on Jetta and Convertible from 2/82
Disconnect Charcoal Canister Purge Hose:
- 1982 VW (except Quantum): Remove charcoal canister purge hose at elbow below intake boot
- 1982 Quantum, Audi 4000, Audi Coupe: Remove cap from “T” piece (1) in charcoal canister purge hose near right fender wall
- 1982 Audi 5000: Remove charcoal canister purge hose at the charcoal canister
Adjust CO% (Oxygen Sensor connected)
- Remove tamper-proof plug from air CO adjustment sensor housing
- Using adjusting tool P377-adjust “duty cycle” to: 50% ± 6% (45 ± 7°)
- Note that the duty cycle reading fluctuates and that it fluctuates within the specified range.
- A duty cycle reading that does not fluctuate indicates a problem within the oxygen sensor system. Check that the CO% value is: 0.3% to 1.2%
- Reconnect crankcase hose(s)
- Reconnect idle stabilizer
- Re-adjust idle speed if necessary
- Re-insert charcoal canister vent hose into front apron.
Perform Hot Start test page 22.
SPECIFICATIONS
Check/Adjust: Timing, idle speed and CO%
Volkswagen
AUDI
