Ignition
90-8M0050731 MAY 2011 Page 2A-13
6. Engine Runs Rough Above 3000 RPM
Cause Action
6.1 Fouled spark plug
Refer to 3.2.
6.2 Speed reduction
Refer to 7.4 and 7.5.
6.3 Low air pressure in rails
Refer to 1.2.
6.4 TPS malfunction
Refer to 2.4.
7. Speed Reduction (RPM reduced)
Cause Action
7.1 Low battery voltage (PCM cuts out below 8 volts)
(fuel pump requires 9 volts)
Check battery and/or alternator.
Check electrical connections.
7.2 Overheat condition (engine and/or air
compressor)
Check water pump impeller/cooling system.
7.3 Oil pump electrical failure Check electrical connection.
7.4 TPS failure
If TPS fails, RPM is reduced to idle
Check electrical connection.
7.5 CPS failure
If CPS fails, the engine will run rough or stop running
Refer to Crankshaft Position Sensor Test.
8. Engine RPM Reduced to Idle Only
Cause Action
8.1 TPS failed
Refer to 2.4.
Use CDS to monitor system.
9. Loss of Spark on One Cylinder
Cause Action
9.1 Loose wire or pin connectors between PCM and
coil primary
Check connectors.
9.2 Faulty ignition coil Replace coil.
9.3 Faulty spark plug Replace spark plug.
9.4 Faulty spark plug wire
Replace spark plug wire.
2.
Wire Color Code Abbreviations
Wire Color Abbreviations
BLK Black
BLU Blue
BRN Brown GRY Gray
GRN Green ORN or ORG Orange
PNK Pink PPL or PUR Purple
RED Red TAN Tan
WHT White YEL Yellow
LT or LIT Light DK or DRK Dark
2. If the spark plug is partially fouled or the plug gap is too small, the CDS may indicate the incorrect cylinder as having an ignition fault. Example: If
the CDS indicates an ignition fault on cylinder #3, the problem may be on the prior cylinder in the firing order ‑ I.E. cylinder number #2.
To Next Page
Loading...
Need help?
General
