Engine Controls - Adjustments Audi Cabriolet I

INTRODUCTION

ENGINE COMPRESSION

Check engine compression with engine oil temperature greater than 86°F (30°C), all spark plugs removed, both power output stage connectors disconnected and throttle wide open.

COMPRESSION SPECIFICATIONS

VALVE CLEARANCE

All model use hydraulic valve lifters. No adjustment is necessary. To check a suspect valve lifter remove valve cover and turn crankshaft clockwise until cam lobe of suspect valve lifter is pointing upwards. If a .008" (.20 mm) feeler gauge can be inserted between camshaft and valve lifter, replace lifter.

IGNITION TIMING

Ignition timing is electronically controlled by Powertrain Control Module (PCM) and cannot be adjusted. See IDLE SPEED & MIXTURE .

IDLE SPEED & MIXTURE

Note. Mixture adjustment is not a part of normal tune-up procedure and should not be performed unless mixture control unit is replaced or vehicle fails emissions testing.

Note. Idle speed is electronically controlled by Powertrain Control Module (PCM) and cannot be adjusted.

Scheme 1

Scheme 2

1. Ensure engine is at normal operating temperature. Turn ignition off. Ensure all electrical accessories and cooling fan are off. Remove cap and pry out plastic plug from CO potentiometer installed in Mass Airflow (MAF) sensor housing. (Scheme 1)
2. Connect CO tester to CO tap tube on right exhaust manifold. (Scheme 2) Read and record CO content. Repeat test on left C O tap tube. Content must be 0.3-1.2% by volume.
3. If CO content is less than 0.3% by volume, eliminate leak in area of CO tap tube or adaptor.
4. If CO content is more than 1.2% by volume, eliminate leak in exhaust system between engine and HO2S.
5. Install NEW plastic plug and press on cap.
6. Check idle speed. Idle RPM must be within specification. See «IDLE SPEED & CO LEVEL SPECIFICATIONS»(/audi/cabriolet/i-1991-2000/remont/adjustments/#engine-controls-adjustments) table. If idle speed is not within specification, check air intake system for leaks. Idle speed is electronically controlled by PCM and is not adjustable. IDLE SPEED & CO LEVEL SPECIFICATIONS Application Idle RPM CO Level Checking Value 700-800 0.3-1.2%
7. If necessary, check differential pressure regulator current with oxygen sensor connected. Reading must fluctuate between -4 and 6 mA and CO level must be 0.3-1.2%.

Note. If idle speed drops severely when A/C system is turned on, check idle stabilization system.

CLOSED THROTTLE POSITION (CTP) SWITCH

Note. Closed Throttle Position (CTP) switch is located within Throttle Position (TP) sensor.

1. Remove noise dampener and disconnect harness connector from throttle body assembly. Using DVOM, measure resistance between TP sensor terminals No. 4 and 6. (Scheme 3) Resistance must be zero oh ms. Operate throttle slightly. Resistance must be infinite. If specified resistance is not obtained or is obtained only after opening throttle further, adjust CTP switch.
2. To adjust CTP switch, remove throttle body assembly. Loosen both TP sensor screws. Turn TP sensor counterclockwise until stop is reached. Ensure linkage is not moved. Tighten TP sensor screws in this position. Install throttle body and adjust cable. (Scheme 4)
3. Check CTP switch again. If specified resistance value is still not obtained, replace TP sensor.

Scheme 3

Scheme 4

KICKDOWN SWITCH

1. Remove noise damper. Disconnect kickdown switch 2-pin harness connector. Using jumpers and a DVOM, measure resistance between terminals No. 1 and 2 of kickdown switch harness connector. Resistance must be infinite.
2. Slowly depress accelerator pedal. Kickdown switch resistance should go to zero ohms (continuity) in range "A" and "B". (Scheme 5) If continuity does not occur, loosen kickdown switch mounting bolts and move throttle lever by hand to wide open throttle position. See step "A" in (Scheme 6).
3. Adjust kickdown switch so that switch lever contacts throttle cam. See step "B" in (Scheme 7). Apply locking compound to mounting bolts and tighten.

Scheme 5

Scheme 6

Scheme 7

RPM SENSOR BRACKET

1. Remove Crankshaft Position (CKP) sensor. Position crankshaft at TDC for No. 3 cylinder. (Scheme 8) Screw Crankshaft Positioner (V.A.G. 3242) into sensor hole. Notch in No. 3 cylinder counterweight can be seen or felt through sensor hole in block. (Scheme 9)
2. Remove heat shield. Remove Engine Speed (RPM) sensor and loosen RPM sensor bracket.
3. Insert RPM Sensor Gauge (V.A.G. 3308) until locked into gear tooth. Push bracket within slots to ensure sensor gauge is locked into gear tooth. Retighten bracket and reinstall RPM sensor.

Scheme 8

Scheme 9

Scheme 10

THROTTLE CABLE

When installing a throttle cable, ensure it is aligned properly between its supports and fixing points. Throttle cable is fixed to accelerator pedal and cam disc. Longitudinal adjustment of throttle cable sleeve is not fixed by securing clip.

1) Fully depress accelerator pedal. Pull back throttle cable sleeve until throttle valve lever rests on the full load stop. See "A" in (Scheme 11). Secure longitudinal adjustment using securing clip. See "B" in (Scheme 11).

2) Depress accelerator pedal fully. Throttle valve lever must rest on the full load stop. Release accelerator pedal completely. Throttle lever must come to rest at idle stop. (Scheme 12) Repeat adjustment if conditions are not met.

Scheme 11

Scheme 12

See also:
• IDLE SPEED & MIXTURE
• IDLE SPEED & CO LEVEL SPECIFICATIONS