Engine Controls - Remove/install/overhaul - Gasoline Volkswagen Corrado I

INTRODUCTION

Note. Information in this article applies to gasoline engine models only.

Removal, overhaul and installation procedures are covered in this article. If component removal and installation is primarily an unbolt and bolt-on procedure, only a torque specification may be furnished. See TORQUE SPECIFICATIONS table.

Removal (AFC-Digifant)

Turn engine crankshaft to TDC. Remove distributor cap. Rotor should point to No. 1 cylinder mark on edge of distributor housing. Index mark distributor housing to crankcase relation. Remove distributor hold-down clamp and bolt. Remove distributor assembly.

Installation

Align rotor with No. 1 cylinder mark on edge of distributor housing. Install distributor and align housing to index mark made on crankcase. Install distributor hold-down clamp and bolt. Install distributor cap. Check timing. Tighten hold-down bolt to specification. See TORQUE SPECIFICATIONS table.

Removal (CIS-E & CIS-E Motronic)

1. Turn engine crankshaft to TDC. Marking on vibration dampener pulley must align with drive belt guard pointer. Marking on cam shaft gear sprocket must align with cylinder head cover.
2. Remove distributor cap and mark position of rotor. Rotor should be pointing to No. 1 cylinder in distributor firing sequence. Mark position of distributor housing for installation reference. Remove distributor hold-down clamp and bolt. Remove distributor assembly, noting position of rotor when distributor shaft gear is disengaged from driving gear.

1. Align oil pump drive pinion lug parallel to crankshaft. Set rotor pointing toward mark made when distributor was disengaged from drive gear.
2. Install distributor. Rotor should now point to mark made for No. 1 cylinder in distributor firing sequence. Align mark for distributor housing and install distributor hold-down clamp and bolt. Install distributor cap. Check timing. Tighten hold-down bolt to specification. See «TORQUE SPECIFICATIONS»(/volkswagen/corrado/i-1988-1995/remont/removal-installation/#engine-controls-removeinstalloverhaul-gasoline) table.

FUEL SYSTEM PRESSURE RELEASE

1. Pinch shut fuel supply line to transfer pump from fuel tank. With a large container under pump and reservoir, disconnect output fuel line to drain reservoir and relieve pressure. Be prepared, with rags, to mop up any to residue escaping container.
2. Locate fuel pressure testing port on end of fuel rail. As an alternative fuel system pressure release, open port slowly, using clean rags to absorb fuel.

Removal

1. Disconnect battery ground lead. Working under vehicle, disconnect harness connector from fuel pump. Thoroughly clean around outside of fuel line unions.
2. Temporarily pinch shut supply line from pump to fuel tank. With a large container under pump and reservoir, disconnect output fuel line to drain reservoir and relieve pressure. On models with CIS, CIS-E or CIS-E Motronic, remove cap nut, fuel line and 2 sealing washers. On Digifant models, remove hose clamp and fuel line. Be prepared, with clean rags, to mop up any residue escaping container. WARNING: Fuel will be discharged! DO NOT smoke or work near heaters or other fire hazards. Keep a fire extinguisher handy.
3. Remove 3 mounting screws from fuel pump retaining ring and pull fuel pump assembly from fuel reservoir.

1. Moisten new "O" ring with fuel and install over fuel pump. Ensure fuel pump filter screen is clean. Install pump in fuel reservoir. Secure retaining ring with 3 screws. Tighten screws evenly, ensuring fuel pump is correctly seated.
2. Reconnect fuel line and harness connector. Use new sealing washers and hose clamps as required. On CIS, CIS-E and CIS-E Motronic models, torque cap nut to 15 ft. lbs. (20 N.m). Reconnect battery ground cable, start engine and check for leaks.

FUEL PUMP CHECK VALVE

Removal & Installation

Clean and disconnect fuel line. With line disconnected, check valve can be removed from pump. Use new sealing washers for both check valve and fuel line union. Torque both parts to 15 ft. lb. (20 N.m).

1. Remove air filter and unscrew stop bracket. Using heat gun, heat locking compound on fastening bolt. Remove bolt slowly. DO NOT damage threads. Clean locking compound from bolt hole threads.
2. Install airflow sensor plate. Ensure 5 dimple marks are up. Lightly tighten self-locking screw. Ensure sensor plate is centered and rest position is correct. To complete installation, reverse removal procedure. See «TORQUE SPECIFICATIONS»(/volkswagen/corrado/i-1988-1995/remont/removal-installation/#engine-controls-removeinstalloverhaul-gasoline) table.

Airflow Sensor Plate Rest Position

Upper edge of sensor plate must be.070-080" (1.80-2.10 mm) below lower edge of sensor cone. (Scheme 1) If rest position is incorrect, raise sensor plate. Open or close wire clip to change position of sensor plate. DO NOT bend leaf spring.

Scheme 1

Scheme 2

1. Check sensor plate for centered position in airflow sensor housing. (Scheme 2) If plate binds on housing or is off-center, remove 6-mm bolt holding plate to lever. Coat bolt with locking compound and install finger tight.
2. Use Centering Gauge (US 1109) or.004" (.10 mm) feeler gauge to set plate an equal distance from sensor housing. If plate cannot be centered, remove airflow sensor housing.
3. Turn housing upside-down and remove counterweight-to-sensor lever bolt. Coat bolt with locking compound and install finger tight. Center sensor plate lever in housing and tighten bolt. Complete centering of plate.

Scheme 3

1. Free play is measured between control piston and adjusting lever. To ensure Differential Pressure Regulator (DPR) current is 4-16 mA, sensor plate lever must be positioned correctly. Measure free play on side of sensor cone closest to fuel distributor. (Scheme 3)
2. Crank starter motor for 10 seconds to develop fuel pressure. Lift sensor plate slightly until resistance is felt. Minimum clearance is any noticeable free play. Maximum clearance is.083" (2.1 mm) up to sensor cone.
3. If free play clearance is incorrect, remove fuel distributor. Check basic adjustment of sensor plate lever. See SENSOR PLATE LEVER ADJUSTMENT below. Recheck free play clearance. If free play clearance is still incorrect, adjust sensor plate clearance with control piston stop screw.

Sensor Plate Lever Adjustment

1. With fuel distributor removed from airflow sensor housing, measure distance between roller on sensor plate lever and contact points of fuel distributor on top of the airflow sensor housing. (Scheme 2)
2. Use a depth gauge or vernier caliper for measuring distance. Distance should be.74-.75" (18.9-19.1 mm). If distance is out of specified range, correct it by adjusting mixture screw.
3. Lightly lubricate new sealing "O" ring and mount on fuel distributor. Install fuel distributor. See «TORQUE SPECIFICATIONS»(/volkswagen/corrado/i-1988-1995/remont/removal-installation/#engine-controls-removeinstalloverhaul-gasoline) table. Connect all fuel lines except those to fuel injectors. Check sensor plate adjusting lever and fuel distributor control piston for smooth operation.
4. Remove fuel pump relay and bridge fuel pump circuit. Use Jumper Switch (US 4480/3) in place of fuel pump relay. When pressure has built up, turn off fuel pump. Move sensor plate from rest position to end of travel.
5. Uniform resistance should be felt during entire movement. No resistance should be felt on quick return to rest position. Connect injector lines. Install fuel pump relay. Start engine and check for leaks.

1. Remove differential pressure regulator. Remove insulating compound covering mounting screws. Remove potentiometer. DO NOT touch or damage slide contact and conductor.
2. To install, reverse removal procedure. Refer to the «TORQUE SPECIFICATIONS»(/volkswagen/corrado/i-1988-1995/remont/removal-installation/#engine-controls-removeinstalloverhaul-gasoline) table. Adjust potentiometer. Refer to th ADJUSTMENTS article.

FUEL DISTRIBUTOR (1.8L ONLY)

1. Disconnect battery and remove air cleaner. Disconnect all fuel and injector lines from fuel distributor. Plug fuel supply and return lines. Use clean rags to catch any fuel spilled.
2. Disconnect wiring from differential pressure regulator. Remove screws holding fuel distributor to airflow sensor housing. Remove fuel distributor by turning back and forth while lifting up. To install, reverse removal procedure.

INJECTORS

1. Disconnect negative battery cable. Disconnect main electrical connector from fuel rail. Remove idle stabilizer valve. Loosen and remove both hoses on each end of fuel rail. Remove fuel pressure regulator and mounting bracket.
2. Remove fuel rail mounting bolts. Pry off injector mounting clips. Disconnect injector electrical connectors. Remove fuel rail. Remove each injector from its insert.

To install injectors, reverse removal procedures. Use new "O" rings when installing injectors. Replace hose clamps if necessary. See TORQUE SPECIFICATIONS table. Check for fuel leaks.

Remove injectors from inserts in cylinder head with fuel lines attached. Using 12-mm or 13-mm hex wrench, remove inserts from head. Use 2 wrenches to remove injectors from fuel lines.

To install, reverse removal procedures. Use 2 wrenches when tightening injector lines to injectors. Use new "O" rings lightly lubricated. On models with 2-piece inserts, replace insert sealing washer (against head) and use sealing compound on upper insert threaded portion. See TORQUE SPECIFICATIONS table.

1. Oxygen (O2) sensor is mounted in exhaust pipe in front of catalytic converter. Disconnect permanent pigtail from sensor. Ensure sensor is free of contaminants, avoid using any cleaning solvents. Sensor may be difficult to remove when engine temperature is less than 118°F (48°C).
2. Always use anti-seize compound on threads before installation. Tighten sensor to specification. See «TORQUE SPECIFICATIONS»(/volkswagen/corrado/i-1988-1995/remont/removal-installation/#engine-controls-removeinstalloverhaul-gasoline) table.

1. Disconnect accelerator cable from linkage. Disconnect return spring on TVH. Remove cruise control connecting rod on TVH (if equipped). Pull off vacuum hoses. Remove TVH mounting nuts.
2. Disconnect throttle valve switch. Remove 2 TVH to metallic front vibration mounts nuts. Disconnect fuel return hose from pressure regulator. Lift sensor housing upward and remove TVH. Remove gasket.
3. To install, reverse removal procedure. Ensure all surfaces are clean and mate correctly. Use new gaskets when assembling. Adjust accelerator linkage and idle speed. See «TORQUE SPECIFICATIONS»(/volkswagen/corrado/i-1988-1995/remont/removal-installation/#engine-controls-removeinstalloverhaul-gasoline) table.

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

See also:
• TORQUE SPECIFICATIONS