Service Diagnosis - Performance - Dodge D150 1990 Service Manual

9 - 8 ENGINE
SERVICE DIAGNOSIS - PERFORMANCE
•
CONDITION POSSIBLE CAUSES CORRECTION
ENGINE WILL NOT START • Weak battery
• Corroded or loose battery connections
• Faulty starter
• Moisture on ignition wires and distributor
cap
• Faulty ignition cables
• Faulty coil or control unit
• Incorrect spark plug gap
• Incorrect ignition timing
• Dirt or water in fuel line
• Faulty fuel pump
• Charge or replace, as necessary. Refer to
Group 8A, Battery/Starting/Charging
System Diagnosis.
• Clean and tighten battery connections.
Apply a coat of light mineral grease to
terminals.
• Refer to Group 8B, Battery/Starter Service.
• Wipe wires and cap clean and dry.
• Replace any cracked or shorted cables.
• Test and replace, if necessary. Refer to
Group 8D
t
Ignition System.
• Set gap. Refer to Group 8D, Ignition
System.
• Refer to Group 8D, Ignition System.
• Clean lines.
• Install new fuel pump. Refer to Group 14,
Fuel System.
ENGINE STALLS OR
ROUGH IDLE
• Idle speed set too low
• Leak in intake manifold
• Worn or burned distributor rotor
• Incorrect ignition wiring
• Faulty coil
• EGR valve leaking
• Refer to Group 14, Fuel System.
• inspect intake manifold gasket and
replace, if necessary. Refer to Group 11,
Exhaust System and Intake Manifold.
• Install new rotor.
• Install correct wiring.
• Test and replace, if necessary. Refer to
Group 8D, Ignition System.
• Test and replace, if necessary. Refer to
Group 25, Emissions.
ENGINE LOSS OF POWER • Incorrect ignition timing
• Worn or burned distributor rotor
• Worn distributor shaft
• Dirty or incorrectly gapped spark plugs
• Dirt or water in fuel line or filter
• Faulty fuel pump
• Incorrect valve timing
• Blown cylinder head gasket
• Low compression
• Burned, warped or pitted valves
• Plugged or restricted exhaust system
• Faulty ignition cables
• Faulty coil
• Refer to Group 8D, Ignition System.
• Install new rotor.
• Remove and repair distributor. Refer to
Group 8D, Ignition System.
• Clean plugs and set gap. Refer to Group
8D, Ignition System.
• Clean lines and replace filter. Refer to
Group 14, Fuel System.
• Install new pump.
• Refer to Valve Timing in this group.
• Instal new cylinder head gasket.
• Test compression of each cylinder.
• Install new valves.
• Install new parts, as necessary.
• Replace any cracked or shorted cables.
• Test and replace, as necessary.
ENGINE MISSES ON
ACCELERATION
• Dirty, or gap too wide in spark plugs
• Incorrect ignition timing
• Burned, warped or pitted valves
• Faulty coil
• Clean spark plugs and set gap. Refer to
Group 8D, Ignition System.
• Refer to Group 8D, Ignition System.
• Install new valves.
• Test and replace, if necessary. Refer to
Group 8D, Ignition System.
ENGINE MISSES AT HIGH
SPEED
• Dirty or gap set too wide in spark plug
• Worn distributor shaft
• Worn or burned distributor rotor
• Faulty coil
• Incorrect ignition timing
• Dirty injector in throttle body
• Dirt or water in fuel line or filter
• Clean spark plugs and set gap. Refer to
Group 8D, Ignition System.
• Remove and repair distributor. Refer to
Group 8D, Ignition System.
• Install new distributor rotor.
• Test and replace, if necessary. Refer to
Group 8D, Ignition System.
• Refer to Group 8D, Ignition System.
• Refer to Group 14, Fuel System.
• Clean lines and replace filter. Refer to
Group 14, Fuel System.
J9009-95