CIS W/OXS System - New Checking/Adjusting Procedures
85VW2Applies To
GOLF
(U..S. models with manual trans. only)
1985
Group
25
Subject
CIS With OXS System
Part Identifier N/A
Key Points
New checking/adjusting procedures
B
Number
85-02
April 17, 1985
Idle speed/ignition timing/OXS-duty cycle (CO value), checking/adjusting
Work sequence
Note
Idle speed, ignition timing and OXS-duty cycle (CO value) must be checked and adjusted together.
Check and adjust CO value only with OXS-duty cycle. CO measurement is only used for crosscheck.
Test conditions:
^ oxygen sensor connected
^ engine oil temperature minimum 80~C (176~F). Radiator fan must come on at least once
^ all electrical sources switched OFF (radiator fan and air conditioner must not be running)
^ pressure gauge not connected
^ if injection line system has been removed or replaced, run engine several times to 3000 rpm for about two minutes before starting checking procedure
^ exhaust system must be free of leaks
- connect tester VW 1367
Note
TDC sending unit must fit snug into transmission housing
- remove cap from CO probe receptacle
- connect CO tester to probe receptacle
^ hose must fit snug so there is no exhaust leak
- pinch hose 1 of idle speed boost valve
- remove hoses for crankcase ventilation and vent to atmosphere
^ hose 2 from intake manifold
^ hose 3 from air filter
- remove carbon canister purge line A from connector B of carbon canister shut off valve
- start engine and run at idle
- check idle speed. If necessary, set adjustment screw 5
^ checking 800-1000 rpm
^ adjusting 920 +/- 30 rpm
- check ignition timing. If necessary, adjust
^ checking 4-8~ BTDC
^ adjusting 6 +/- 1.5~ BTDC
- disconnect testor lead from terminal 1 of ignition coil and connect to OXS test connection at arrow (blue/white and brown wires) using harness adaptor US 1112
- remove testor lead from spark plug wire no. 1
- remove TDC sensor from transmission
- press % button on testor
- start engine
- check OXS-duty cycle (dwell) at idle speed
Note
Pay no attention to figures displayed in rpm window of testor VW 1367
- check OXS-duty cycle and CO reading
^ OXS-duty cycle must read 25-65% (23-59~ dwell) (reading must fluctuate)
^ CO must read between 0.3-1.0%
If CO reading is higher than 1.0% with OXS-duty cycle reading correct
- check following and repair as necessary
^ leaking exhaust system
^ leaks in intake system
^ uneven fuel distribution by fuel distributor
^ injector spray pattern incorrect
If OXS-duty cycle reading NOT OK
- adjust with CO adjusting screw as follows
- stop engine
- remove boot on mixture-control unit
- center-punch plug in CO adjusting hole
- drill 2.5 mm (3/32 in.) hole in center of plug 3.5-4.0 mm (9/64-5/32 in.) deep
CAUTION
Clean up any metal shavings. Apply grease to drill bit to catch shavings.
- screw in 3 mm (1/8 in.) sheet-metal screw
- remove plug with screw, using pliers
- start engine and run at idle
- adjust OXS-duty cycle by turning CO adjusting screw with tool P377
^ turn screw clockwise to lower meter reading
^ turn screw counterclockwise to raise meter reading
- adjust OXS-duty cycle
^ reading must fluctuate between 44-56% (40-50~ dwell)
CAUTION
When adjusting, do not push adjustment wrench down. Do not accelerate engine with tool in place. Remove tool after each adjustment and accelerate engine briefly before reading meter. Radiator fan must not be running while adjusting.
- readjust idle speed if necessary
- turn ignition OFF
- drive in new plug flush with mixture control unit
- remove CO meter and reinstall CO probe cap
- reconnect crankcase breather hoses
- reconnect charcoal cannister hose to vacuum shut-off valve