VOLKSWAGEN CORRADO 1990 Repair Manual

ENGINE OVERHAUL PROCEDURES - GENERAL INFORMATION
Article Text (p. 32)
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:44PM
zero. Rotate camshaft gear in opposite direction as far as possible
and note reading.
To determine timing gear runout, mount dial indicator with
tip resting on face edge of camshaft gear. Adjust indicator to zero.
Rotate camshaft gear 360 degrees and note reading. If backlash or
runout exceed specifications, replace camshaft and/or crankshaft
gear.
REAR MAIN OIL SEAL
* PLEASE READ THIS FIRST *
NOTE: Always refer to appropriate engine overhaul article in the
ENGINES section for complete overhaul procedures and
specifications for the vehicle being repaired.
INSTALLATION
One-Piece Type Seal
For one-piece type oil seal installation, coat block contact
surface of seal with sealer if seal is not factory coated. Ensure seal
surface is free of burrs. Lubricate seal lip with engine oil and press
seal into place using proper oil seal installer. See Fig. 27.Fig. 27: Installing Typical One-Piece Oil Seal
This Graphic For General Information Only
Rope Type Seal
For rope type rear main oil seal installation, press seal
lightly into its seat. Using seal installer, fully seat seal in
bearing cap or cylinder block.
Trim seal ends even with block parting surface. Some
applications require sealer to be applied on main bearing cap prior
to installation. See Fig. 28.

ENGINE OVERHAUL PROCEDURES - GENERAL INFORMATION
Article Text (p. 33)
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:44PMFig. 28: Typical Rope Seal Installation
This Graphic For General Information Only
Split-Rubber Type Seal
Follow manufacturers procedures when installing split-rubber
type rear main oil seals. Installation procedures vary with engine
type. See appropriate ENGINE article in this section. See Fig. 29.Fig. 29: Typical Split-Rubber Seal Installation
This Graphic For General Information Only
OIL PUMP
* PLEASE READ THIS FIRST *
NOTE: Always refer to appropriate engine overhaul article in the
ENGINES section for complete overhaul procedures and
specifications for the vehicle being repaired.
ROTOR-TYPE
Oil pump rotors must be marked for location prior to removal.
See Fig. 30. Remove outer rotor and measure thickness and diameter.
Measure inner rotor thickness. Inspect shaft for scoring or wear.
Inspect rotors for pitting or damage. Inspect cover for grooving or
wear. Replace components if worn or damaged.

ENGINE OVERHAUL PROCEDURES - GENERAL INFORMATION
Article Text (p. 34)
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:44PMFig. 30: Typical Rotor Type Oil Pump
This Graphic For General Information Only
Measure outer rotor-to-body clearance. Replace pump assembly
if clearance exceeds specification. Measure clearance between rotors.
See Fig. 31. Replace shaft and both rotors if clearance exceeds
specifications.Fig. 31: Measuring Rotor Clearance - Typical
This Graphic For General Information Only
Install rotors in pump body. Position straightedge across
pump body. Using feeler gauge, measure clearance between rotors and
straightedge. Pump cover wear is measured using a straightedge and
feeler gauge. Replace pump if clearance exceeds specification.
GEAR TYPE
Oil pump gears must be marked for location prior to removal.
See Fig. 32. Remove gears from pump body. Inspect gears for pitting
or damage. Inspect cover for grooving or wear.

ENGINE OVERHAUL PROCEDURES - GENERAL INFORMATION
Article Text (p. 35)
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:44PMFig. 32: Typical Gear Type Oil Pump
This Graphic For General Information Only
Measure gear diameter and length. Measure gear housing cavity
depth and diameter. See Fig. 33. Replace components if worn or
damaged.
Pump cover wear is measured using a straightedge and feeler
gauge. Pump is to be replaced if warpage or wear exceeds
specifications or mating surface of pump cover is scratched or
grooved.Fig. 33: Measuring Oil Pump Gear Cavity - Typical
This Graphic For General Information Only
BREAK-IN-PROCEDURE
* PLEASE READ THIS FIRST *
NOTE: Always refer to appropriate engine overhaul article in the
ENGINES section for complete overhaul procedures and
specifications for the vehicle being repaired.
ENGINE PRE-OILING
Engine pre-oiling should be done prior to operation to
prevent engine damage. A lightly oiled pump will cavitate unless oil
pump cavities are filled with engine oil or petroleum jelly.
Engine pre-oiling can be done using pressure oiler (if
available). Connect pressure oiler to cylinder block oil passage
such as oil pressure sending unit. Operate pressure oiler long enough

ENGINE OVERHAUL PROCEDURES - GENERAL INFORMATION
Article Text (p. 36)
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:44PM
to ensure correct amount of oil has filled crankcase. Check oil level
while pre-oiling.
If pressure oiler is not available, disconnect ignition
system. Remove oil pressure sending unit and replace with oil pressure
test gauge. Using starter motor, rotate engine starter until gauge
shows normal oil pressure for several seconds. DO NOT crank engine
for more than 30 seconds to avoid starter motor damage.
Ensure oil pressure has reached the most distant point from
the oil pump. Reinstall oil pressure sending unit. Reconnect ignition
system.
INITIAL START-UP
Start the engine and operate engine at low speed while
checking for coolant, fuel and oil leaks. Stop engine. Recheck coolant
and oil level. Adjust if necessary.
CAMSHAFT
Break-in procedure is required when a new or reground
camshaft has been installed. Operate and maintain engine speed between
1500-2500 RPM for approximately 30 minutes. Procedure may vary due to
manufacturers recommendations.
PISTON RINGS
Piston rings require a break-in procedure to ensure seating
of rings to cylinder walls. Serious damage may occur to rings if
correct procedures are not followed.
Extremely high piston ring temperatures are produced obtained
during break-in process. If rings are exposed to excessively high RPM
or high cylinder pressures, ring damage can occur. Follow piston ring
manufacturer's recommended break-in procedure.
FINAL ADJUSTMENTS
Check or adjust ignition timing and dwell (if applicable).
Adjust valves (if necessary). Adjust carburetion or injection idle
speed and mixture. Retighten cylinder heads (if required). If
cylinder head or block is aluminum, retighten bolts when engine is
cold. Follow the engine manufacturer's recommended break-in procedure
and maintenance schedule for new engines.
NOTE: Some manufacturer's require that head bolts be retightened
after specified amount of operation. This must be done to
prevent head gasket failure.
END OF ARTICLE

F - BASIC TESTING
Article Text
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:44PM
ARTICLE BEGINNING
1990 ENGINE PERFORMANCE
Volkswagen Basic Diagnostic Procedures
Cabriolet, Corrado, Fox, Golf GL/GTI, Jetta, Vanagon
INTRODUCTION
The following diagnostic steps will help prevent overlooking
a simple problem. This is also where to begin diagnosis for a no start
condition.
The first step in diagnosing any driveability problem is
verifying the customer's complaint with a test drive under the
conditions the problem reportedly occurred.
Perform a careful and complete visual inspection. Most engine
control problems result from mechanical breakdowns, poor electrical
connections or damaged/misrouted vacuum hoses. Before condemning the
computerized system, perform each test listed in this article.
NOTE: Perform all voltage tests with a Digital Volt-Ohmmeter
(DVOM) with a minimum 10-megohm input impedance, unless
stated otherwise in test procedure.
VISUAL INSPECTION
Visually inspect all electrical wiring, looking for chafed,
stretched, cut or pinched wiring. Ensure electrical connectors fit
tightly and are not corroded. Ensure vacuum hoses are properly routed
and are not pinched or cut. See M - VACUUM DIAGRAMS article to verify
routing and connections (if necessary). Inspect air induction system
for possible vacuum leaks.
MECHANICAL INSPECTION
COMPRESSION
Check engine mechanical condition with a compression gauge,
vacuum gauge, or an engine analyzer. See engine analyzer manual for
specific instructions.
DO NOT use ignition switch during compression tests on fuel
injected vehicles. Use a remote starter to crank engine. Fuel
injectors on many models are triggered by ignition switch during
cranking mode, which can create a fire hazard or contaminate the
engine's oiling system.
EXHAUST SYSTEM BACKPRESSURE
The exhaust system can be checked with a vacuum or pressure
gauge. Remove O2 sensor or air injection check valve (if equipped).
Connect a 1-10 psi pressure gauge and run engine at 2500 RPM. If

F - BASIC TESTING
Article Text (p. 2)
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:44PM
exhaust system backpressure is greater than 1 3/4-2 psi, exhaust
system or catalytic converter is plugged.
If a vacuum gauge is used, connect vacuum gauge hose to
intake manifold vacuum port and start engine. Observe vacuum gauge.
Open throttle part way and hold steady. If vacuum gauge reading slowly
drops after stabilizing, exhaust system should be checked for a
restriction.
FUEL SYSTEM APPLICATION TABLE
FUEL SYSTEM APPLICATION TABLEÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄApplication Fuel System
Cabriolet, Corrado, Golf GL/GTI
Jetta & Vanagon ........................ AFC-Digifant II
Fox ................................................ CIS-E
Jetta GLi ................................... CIS-Motronic
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ FUEL PRESSURE CHECK
Basic diagnosis of fuel system should begin with determining
fuel system pressure.
FUEL PUMP CIRCUIT CHECK
Remove fuel tank cap. Turn ignition on and listen for fuel
pump operating sound for approximately 2 seconds. If there is no
sound, check fuse, fuel pump relay, fuel pump and all electrical
connections.
VISUAL CHECK (AFC-DIGIFANT II)
Push air door open, slight resistance should be felt and door
should not bind. Uniform resistance should be felt throughout travel
after slight amount of free travel. No binding should be felt when air
door is released.
VISUAL CHECK (CIS-E & CIS-MOTRONIC)
Move sensor plate slowly upward. Sensor plate should have
slight resistance from control piston adjusting lever. No binding
should be felt. Let sensor plate fall. There should no resistance.
Slight fuel seepage past control piston is acceptable.
FUEL PRESSURE TEST
WARNING: ALWAYS relieve fuel pressure before disconnecting any fuel
injection-related component. DO NOT allow fuel to contact
engine or electrical components.

F - BASIC TESTING
Article Text (p. 3)
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:44PM
CABRIOLET, GOLF GL/GTI, JETTA WITH AFC-DIGIFANT II
1) Install Fuel Pressure Gauge at service port on fuel
plenum. Fuel pressure gauge must be able to read 0-50 psi. Start
engine and allow it to idle. System fuel pressure should be
approximately 36 psi (2.5 kg/cmý).
2) Disconnect vacuum hose from top of the fuel pressure
regulator. Fuel pressure should increase to approximately 44 psi (3.0
kg/cm
ý). Turn engine off. After 10 minutes, residual pressure should
be 29 psi (2.0 kg/cm
ý). If system pressure is too high, the fuel
pressure regulator should be replaced.
3) If residual pressure is too low, run the engine until
system pressure is built up, pinch off Blue fuel return line. If
pressure holds, replace the fuel regulator.
CORRADO WITH AFC-DIGIFANT II
1) Install Fuel Pressure Gauge (VW 1318) and Adaptor (VW
3118-1 and 11) between the fuel distributor test port and pressure
switch. Bleed excess air from system cycling control valve with gauge
upside down.
2) Open fuel pressure gauge control lever, start engine and
allow to idle. Fuel pressure should be approximately 36.3 psi (2.5
kg/cm
ý). Pull hose off intake manifold fuel pressure should increase
to approximately 43.5 psi (3.0 kg/cm
ý).
3) Switch ignition off. After 10 minutes residual pressure
should be 29 psi (2.0 kg/cm
ý). If residual pressure is too low, run
the engine until system pressure is built up, pinch off Blue fuel
return line. If pressure holds, replace the fuel regulator.
If fuel pressure is low, check the following:
* Fuel lines for leaks.
* Fuel injectors leaking.
* Fuel pump check valve leaking.
* Pressure gauge stop-cock leaking.
FOX & JETTA GLI WITH CIS-E & CIS-MOTRONIC
1) Connect pressure gauge (VW 1318) between fuel distributor
port and the end of the fuel line to cold start valve. Ensure control
lever is in the closed position. See Fig. 1. Bleed excess air from
system by cycling control valve with gauge upside down.
2) Open fuel pressure gauge control lever. Start engine allow
to run. System fuel pressure should 75-82 psi (5.2-5.6 kg/cm
ý). On
Jetta GLi system pressure should be 89-95 psi (6.1-6.6 kg/cm
ý). If
system fuel pressure is low, perform fuel volume check. If fuel volume
is okay, replace fuel pressure regulator.
3) If fuel pressure is above specification, remove return
hose from pressure regulator and repeat test. If system pressure is
okay, check for restricted fuel return line. If pressure is incorrect,
replace fuel pressure regulator.

F - BASIC TESTING
Article Text (p. 4)
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:44PMFig. 1: Testing Fuel Pump Pressure (CIS-E & CIS-Motronic)
Courtesy of Volkswagen United States, Inc.
VANAGON WITH AFC-DIGIFANT II
1) Install Fuel Pressure Gauge (VW 1318) at fuel supply hose
3-way "T" connector. See Fig. 2. Using a jumper wire, connect
terminals No. 30 and 87 on fuel pump relay.
2) Turn ignition on. With fuel pump operating, minimum
pressure should be 33 psi (2.2 kg/cmý). If fuel pressure is incorrect,
inspect for restricted fuel lines, defective fuel pump or weak control
pressure regulator. If okay, perform MAIN FUEL PUMP VOLUME CHECK.Fig. 2: Testing Fuel Pump Pressure (Vanagon)
Courtesy of Volkswagen United States, Inc.
REGULATED FUEL PRESSURE TABLE
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Engine Off (1) At Idle
Application psi (kg/cm
ý) psi (kg/cmý)
Cabriolet, Corrado,
Golf GL/GTI & Jetta .... 29-36 (2.0-2.5) ........ 75-82 (5.2-5.6)
Fox ....................... 38.0 (2.6) ........... 75-82 (5.2-5.6)
Jetta GLi ................. 48.0 (3.3) ........... 89-95 (6.1-6.6)
Vanagon ................. 29-36 (2.0-2.5) ........... (2) 33 (2.2)
(1) - After checking fuel pressure at idle, turn ignition switch

F - BASIC TESTING
Article Text (p. 5)
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:44PM
to OFF position.
(2) - With pressure regulator vacuum hose disconnected, pressure
should be 36 psi (2.5 kg/cmý).
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ TRANSFER PUMP CHECK
TRANSFER PUMP FUEL VOLUME CHECK
1) Turn ignition off. To check transfer pump (in tank),
remove rear seat. Remove fuel sending unit access cover. Disconnect
ignition coil secondary wire and jumper to ground. With transmission
in neutral, crank engine for a 3-4 seconds. While the starter is
turning and for a few seconds afterwards, an audible sound should be
heard at the pump. If not, proceed to step 2).
2) Activate fuel pumps by removing fuel pump relay and
attaching jumper wire between terminals No. 30 battery voltage and No.
87 output to fuel pumps. Terminal identification is molded on
fuse/relay panel. If pump does not operate, remove transfer pump
wiring harness connector. See Fig. 3.
3) Using test light, check for voltage between Brown (-) and
Green (+) wire at connector. If voltage is present, replace transfer
pump. If not, repair open or short circuit in wiring.
4) If transfer pump operates correctly, remove fuel pump
relay jumper wire. Disconnect and plug transfer pump output hose.
Attach a hose to pump outlet connector and place other end of hose in
a graduated container. Activate fuel pump for 10 seconds.
5) Minimum fuel flow for CIS-E should be 13.5 ounces (.4
liters). Minimum fuel flow for CIS-Motronic and AFC-Digifant II should
be 10.0 ounces (.3 liters). If fuel flow is low, check fuel tank
filter for restriction. If okay, replace transfer pump.Fig. 3: Checking Transfer Pump Fuel Volume (Fox & Jetta GLi)
(Others Similar)
Courtesy of Volkswagen United States, Inc.
NOTE: Before testing main fuel pump, check transfer pump. See
TRANSFER PUMP FUEL VOLUME CHECK in this article.
MAIN FUEL PUMP VOLUME CHECK