Cis/OXS System - New Checking/Adjusting Procedures (GROUP 25, NO. 86-03)

Publication date: 1986-05-07
Reference number: GROUP 25, NO. 86-03
Supersedes refnos: GROUP 25, NO. 86-02

CIS/OXS SYSTEM - NEW CHECKING/ADJUSTING PROCEDURES

TECHNICAL SERVICE BULLETIN

Reference Number(s): GROUP 25, NO. 86-02, GROUP 25, NO. 86-03, Date of Issue: May 7, 1986
Superceded Bulletin(s): Group 25, Number 86-02, Date of Issue: March 3, 1986

CIS WITH OXS SYSTEM - NEW CHECKING/ADJUSTING PROCEDURES

Model(s): 1985-86 Volkswagen Golf, Jetta

Group: 25 - Continuous Fuel Injection

Bulletin No.: 86-03

Part Identifier: N/A

Date: May 7, 1986

NOTE: This article supersedes Product Circular Group 25, Number 86-02 Dated March 3, 1986.

SERVICE INFORMATION

NOTE: The 1.8L "GX" engine will be offered in two versions. One version with CIS/E and a second version with CIS.

For repairs on the CIS injection system, Group 25 "CIS" applies, as well as the repair instructions listed here.

IDLE ADJUSTING

NOTE: Idle speed, ignition timing and OXS-duty cycle (CO value) must be checked and adjusted together. The oxygen sensor must remain connected during testing or adjustment.

TESTING AND ADJUSTMENT CONDITIONS

Engine oil temperature min. 80°C (176°F).
Electrical consumers turned off (including radiator fan).
A/C off.
If fuel lined were disconnected or replaced, bring up idle speed to 3000 rpm several times and let engine idle for at least 2 minutes.
There must be no leaks in exhaust system.
Oxygen regulation OK.

Clamp hose (1) of idle speed boost valve together tightly.

Pull off crankcase breather hoses and place so that only fresh air can enter.

Hose (2) from intake manifold.
Hose (3) from air filter.
Remove "T" connection (4) from carbon canister at intake air boot.
Turn "T" piece 90° and insert blank side with 1.5mm (0.059 in.) restrictor into hole in intake air boot. See Fig 1 .

NOTE: If car is not equipped with this type of connector, use part #026-133-382D or equivalent plug with 1.5mm (0.059 in) orifice.

IDLE SPEED/IGNITION TIMING/OXS-DUTY CYCLE (CO VALUE), CHECKING/ADJUSTING

WORK SEQUENCE

Connect duty cycle meter VW 1367 or Siemens 451 for measuring ignition timing and rpm.

Run engine at idle.

Check Ignition timing, and adjust if necessary.

Speed under 1000 RPM.
Checking specification: 4 - 8° BTDC
Adjusting specification: 6 +/- 1° BTDC

Check idle speed, if necessary adjust with idle adjusting screw (5). See Fig 1 .

Checking specification: 800 - 1000 RPM.
Adjusting specification: 900 +/- 30 RPM.

For measuring OCS duty, connect VW 1367 or Siemens 451 with adapter US 1112 to connector (1) (Duty Cycle Adaptor Terminal, On-board Vehicle) and press button "<%". See Fig 2 .

CAUTION: Inductive pickup (on VW 1367) must NOT be connected.

Remove cap from CO measuring pipe and connect CO test equipment hose.

CAUTION: Hose must fit tightly on measuring pipe, so that are no exhaust leaks.

OXS DUTY CYCLE FOR DUTY CYCLE VALVE AND CO CONTENT, CHECKING

CHECKING SPECIFICATIONS:

OXS duty cycle 20-70% reading must fluctuate.
CO-content 0.3-1.2%.

NOTE: If the CO content is more than 1.2% by volume at an OXS duty cycle reading of 20-70%, this is not caused by incorrect CO adjustment.

POSSIBLE CAUSES

Ignition system not OK.
Leak in exhaust system.
Fuel injector seats loose or leaking.
Fuel distributor defective (different injection quantities between cylinders at idle).

If the OXS duty cycle reading is less than 20% or greater than 70%, adjust OXS duty cycle to adjusting specifications with the CO adjusting screw as follows.

Remove boot on mixture control unit.

Center punch mixture adjusting screw plug.

Drill 2.5 mm (3/32 in.) hole in center of plug 3.5-40 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 with CO adjusting screw (6). See Fig 3 .

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.

NOTE: After adjusting the idle, the crankcase breather hoses have to be reconnected. If the OXS duty cycle reading and CO content change when they are reconnected, it is not caused by incorrect adjustment, but because of oil thinning due to excessive short distance driving. Longer, high speed driving, with minimal stop and go, will decrease the amount of fuel in the oil, resulting in increased stabilization of OXS duty cycle and CO content. The condition can be temporarily corrected by changing the oil.

EMISSION CONTROL COMPONENTS

Control unit - See Fig 4 .

Location - Control Unit (1) is installed in the left side of the plenum.

Oxygen sensor - See Fig 4 .

Location - The oxygen sensor (2) is positioned in the exhaust manifold.

Relay locations (Golf) - See Fig 5 .
Relay locations (Jetta) - See Fig 6 .

2 = fuel pump relay

15 = Power supply relay for Lambda Control

16 = Idle speed stabilization relay

Thermoswitch - See THERMOSWITCH, CHECKING.
Duty cycle valve - See DUTY CYCLE VALVE, CHECKING.
Catalytic converter same as CIS-E engines.

THERMOSWITCH, CHECKING

Location, see (A), Fig 7 .

Check resistance on contacts.

Specified value: over 28°C (82°F) infinite ohms/under 15°C (59°F) 0.0 ohms

If NO

Replace Thermoswitch.

EMISSION CONTROLS, CHECKING (WITH ENGINE NOT RUNNING)

CONNECTING TEST EQUIPMENT

To measure OXS duty cycle, connect VW 1367 or Siemens 451 with adapter US 1112 on connector (1) and press button "<%". See Fig 2 .

CAUTION: Inductive pickup (on VW 1367) must NOT be connected.

Remove connector (2) of auxiliary air regulator (1) and connect it to connector (3) of the remote control US 4480/3.

Connect alligator clip (4) to battery (+). See Fig 8 .

DUTY CYCLE VALVE, CHECKING

Operate switch on remote control US 4480/3.

Duty cycle valve must audibly click.

If duty cycle valve clicks, continue with test (B) (checking control unit).

If duty cycle valve does not click, perform the following test.

Remove connector from duty cycle valve. See Fig 9 .

Check prongs of the connector and of the duty cycle valve for correct positioning (must not be damaged or pushed in).

Measure voltage supply with multimeter US 1119.

NOTE: Preset multimeter to the 20VDC range prior to making test connection.

Operate remote control US4480/3.

Specification - approx. battery voltage.

If NO

Check for open circuit to duty cycle valve, power supply relay, and control unit.

Make corrections if necessary.

If NO open circuits

Replace power supply relay.

If voltage spec. is NOT obtained

Replace control unit.

Measure duty cycle valve resistance.

Specification - 2-3 ohms.

If NO

Replace duty cycle valve.

CONTROL UNIT, CHECKING

COLD RUNNING ENRICHMENT MODE

Remove wires from thermoswitch (A) and bridge them (B). See Fig 10 .

Operate remote control US 4480/3.

Duty cycle constant 80 +/- 2%.

If NO

Check for breaks in wiring using appropriate current flow diagram.

Make corrections as necessary.

If NO breaks in wiring:

Replace control unit.

Repeat test.

STAND-BY MODE

Remove bridge (B). See Fig 10 .

Operate remote control US 4480/3.

Duty cycle constant 50 +/- 2%.

If NO

Check for breaks in wiring using appropriate current flow diagram.

Make corrections as necessary.

If NO breaks in wiring:

Replace control unit.

Check thermoswitch.

Repeat test.

OXYGEN SENSOR REGULATING FUNCTION OF CONTROL UNIT

Remove wires from thermoswitch.

Pull apart connector for oxygen sensor cable and hold connector (1) of the green cable on ground (A). See Fig 11 .

Operate remote control US 4480/3.

Duty cycle must exceed 87%.

If NO

Check for breaks in wiring using appropriate current flow diagram.

Make corrections if necessary.

If No breaks in wiring: control unit is defective.

Replace control unit.

Connect a 1.5 volt (flashlight type) battery as follows:

(+) terminal to oxygen sensor and green wire, (-) to ground. See Fig 11 .

Operate remote control US 4480/3.

Duty cycle must fall below 20%.

If NO: control unit is defective.

Replace control unit.

Repeat test.

OXYGEN SENSOR, CHECKING

TEST CONDITIONS

Engine oil temperature, min. 80°C (176°F).
Idle adjustment OK.
Control unit oxygen regulating function OK.
Remote control US 4480/3 not connected.
Oxygen sensor connected.

Connect test equipment for measuring OXS duty cycle. See Fig 2 .

Start engine and let idle for at least 2 min.

Clamp hose (1) of idle speed stabilizer valve together tightly. See Fig 12 .

Remove hose (2) from connecting piece on intake manifold. See Fig 12 .

Hold connecting piece on intake manifold closed and note reading on test equipment.

Duty cycle reading must drop.

If NO

Replace oxygen sensor.

Fig 1: Adjusting Idle

Fig 2: Connecting Duty Cycle Meter VW 1367

Fig 3: CO Adjusting Screw

Fig 4: Control Unit/Oxygen Sensor

Fig 5: Relay Locations (Golf)

Fig 6: Relay Locations (Jetta)

Fig 7: Thermostat Location (A)

Fig 8: Connecting Remote Control US 4480/3

Fig 9: Duty Cycle Valve Connector

Fig 10: Thermoswitch Location

Fig 11: Oxygen Sensor Connector

Fig 12: Idle Stabilizer Valve Hose, Clamping