Volkswagen Corrado (1993 year). Manual - part 154

 

  Index      Volkswagen     Volkswagen Corrado - service repair manual 1993 year

 

Search            

 

 

 

 

 

 

 

 

 

Content   ..  152  153  154  155   ..

 

 

Volkswagen Corrado (1993 year). Manual - part 154

 

 

I - SYSTEM/COMPONENT TESTS 

         HALL EFFECT SENSOR

         Corrado SLC (2.8L)
         Testing information is not available from manufacturer. These
vehicles are equipped with a distributorless ignition system.

         FUEL SYSTEM

         ACCELERATION/FULL THROTTLE ENRICHMENT & DECELERATION FUEL

         CUT-OFF

         Corrado SLC (2.8L)
         1) Ensure engine coolant temperature is at least 176

ø

F

(80

ø

C). Connect Scan Tester (VAG 1551) to Data Link Connectors (DLC)

located in center console, in front of shift lever.
         2) Start engine and allow it to idle. With scan tester in
READ TEST VALUE BLOCK function, select group No. 04 and read value in
field No. 4 of scan tester. Display value must be 00010 at idle.
         3) Using accelerator pedal, increase engine speed to 3000 RPM
and observe scan tester. Display value in field No. 4 of scan tester
must briefly be 10100. Release accelerator pedal and observe scan
tester.
         4) Display value in field No. 4 of scan tester must briefly
be 00011, then return to 00010 at idle. If values are not as
specified, see THROTTLE POSITION (TP) SENSOR ADJUSTMENT procedures in
the D - ADJUSTMENTS article. If values are as specified, select END
OUTPUT function on scan tester.

         FUEL INJECTORS & CIRCUIT

         Corrado SLC (2.8L)
         1) To access fuel injectors, remove ignition wires. Remove
hose from mass airflow sensor. Disconnect hose to fuel evaporative
(frequency) solenoid valve at throttle body.
         2) Disconnect throttle position sensor and idle air control
valve. Disconnect accelerator cable from throttle body. Disconnect and
plug coolant hoses at throttle body.
         3) Disconnect hose from air intake heated tube. Detach fuel
lines at cylinder head cover and remove from fuel rail. Disconnect
vacuum hose from fuel pressure regulator. Remove intake manifold upper
section. See Fig. 2.
         4) With intake manifold upper section removed, disconnect
wiring harness from fuel injectors. Using a Digital Volt-Ohmmeter
(DVOM) and test leads from Adapter Kit (VW 1594), check fuel injector
resistance. See Fig. 3.
         5) Fuel injector resistance should be 15.0-21.5 ohms. If
resistance is zero ohms, check for a short circuit in wiring harness.

I - SYSTEM/COMPONENT TESTS 

Fig. 2:  Accessing Fuel Injectors (Corrado SLC)
Courtesy of Volkswagen United States, Inc.

         6) With wiring harness and fuel injectors okay, disconnect
ignition coil power output stage. Using test leads from adapter kit,
check voltage supply to each injector by connecting LED tester between
wiring harness connector terminals. See Fig. 3.
         7) Crank engine and observe LED tester. LED tester must
flicker. If LED tester does not flicker, reconnect wiring harness
connector(s) to fuel injector(s). Check wiring harness for an open
circuit between fuel injector(s) and Engine Control Module (ECM).
         8) If LED tester flickers, remove fuel rail assembly (leaving
fuel lines and injectors attached). Use test leads and fuel rail hose
extensions if necessary. Disconnect Blue Engine Coolant Temperature
(ECT) sensor. Connect the 15,000 ohm side of Adapter (VAG 1490)
directly to ECT sensor wiring harness connector.
         9) Place injectors in Fuel Analyzer (VAG 1602). Crank engine
and observe injectors. Injector spray pattern must be the same for all
injectors. Turn ignition on for 5 seconds and check fuel injectors for
leaks. No more than 2 drops are permissible per minute. When

I - SYSTEM/COMPONENT TESTS 

Fig. 3:  Testing Fuel Injectors & Circuit (Corrado SLC)
Courtesy of Volkswagen United States, Inc.

         OXYGEN SENSOR CONTROL

         IDLE CONTROL SYSTEM

         IDLE AIR CONTROL (IAC) VALVE

         Corrado SLC (2.8L)
         1) Connect Scan Tester (VAG 1551) to Data Link Connectors
(DLC) located in center console, in front of shift lever. With scan
tester in OUTPUT DIAGNOSTIC TEST MODE, test IAC valve. For more
information, see the G - TESTS W/CODES article in this section.

         2) To check IAC valve triggering circuit, turn ignition off.
Disconnect wiring harness connector from idle air control valve.
Connect LED Tester (US 1115) to wiring harness connector terminals No.
1 and 2.
         3) Turn ignition on. Perform OUTPUT DIAGNOSTIC TEST MODE
until IAC valve is triggered. LED tester must flash. If LED tester
does not flash, check IAC valve circuit.
         4) If LED tester flashes, disconnect wiring harness connector
from idle air control valve. Using Test Leads from Adapter Kit (VW
1594), connect DVOM to IAC valve terminals No. 1 and 2. IAC valve
resistance must be 10-20 ohms. If resistance is incorrect, replace IAC
valve.

         IGNITION SYSTEM

NOTE:    Ignition system testing information is not available
         from manufacturer. These vehicles are equipped with a
         distributorless ignition system.

I - SYSTEM/COMPONENT TESTS 

         EMISSION SYSTEMS & SUB-SYSTEMS

NOTE:    Other than EGR system, additional emission systems and
         sub-system component testing information is not available
         from manufacturer.

         EXHAUST GAS RECIRCULATION (EGR)

         Corrado SLC (2.8L)
         1) Ensure engine coolant temperature is at least 122

ø

F

(50

ø

C). Start engine and allow it to idle. Disconnect vacuum hose from

EGR valve. See Fig. 4. Connect hand-held vacuum pump to EGR valve and
apply vacuum.
         2) Idle quality must noticeably deteriorate. If idle quality
does not change, check EGR valve and exhaust manifold for plugging.
Replace EGR valve if necessary. After repairs, erase DTC memory.

Fig. 4:  Testing EGR System (Corrado SLC)
Courtesy of Volkswagen United States, Inc.

 

 

 

 

 

 

 

Content   ..  152  153  154  155   ..