AA - USING THIS SECTION (GENERAL HELP INFORMATION)
Article Text (p. 6)
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:41PM
1) If no self-diagnostics available, or no trouble codes
present, identify symptom.
2) See trouble shooting procedure to repair complaint. See H
- TESTS W/O CODES
TEST SYSTEM
1) Perform necessary systems and component tests. See I -
SYS/COMP TESTS.
2) Verify that complaint is repaired.
SAFETY PRECAUTIONS
* Always refer to Engine Tune-Up Decal in engine compartment before
performing tune-up. If manual and decal differ, always use decal
specifications.
* DO NOT allow or create a condition of misfire in more than one
cylinder for an extended period of time. Damage to converter may
occur due to loading converter with unburned air/fuel mixture.
* Always turn ignition off and disconnect negative battery cable
BEFORE disconnecting or connecting computer or other electrical
components.
* DO NOT drop or shock electrical components such as computer,
airflow meter, etc.
* DO NOT use fuel system cleaning compounds that are not
recommended by the manufacturer. Damage to gaskets, diaphragm
materials and catalytic converter may result.
* Before performing a compression test or cranking engine using a
remote starter switch, disconnect coil wire from distributor and
secure it to a good engine ground, or disable ignition.
* Before disconnecting any fuel system component, ensure fuel
system pressure is released.
* Use a shop towel to absorb any spilled fuel to prevent fire.
* DO NOT create sparks or have an open flame near battery.
* If any EFI components such as hoses or clamps are replaces,
ensure they are replaced with components designed for EFI use.
* Always reassemble throttle body components with new gaskets, "O"
rings and seals.
* If equipped with an inertia switch, DO NOT reset switch until
fuel system has been inspected for leaks.
* Wear safety goggles when drilling or grinding.
* Wear proper clothing which protects against chemicals and other
hazards.
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
