Toyota 4-Runner 1985 Repair Manual page 35

EM-6
ENGINE MECHANICAL -
Troubleshooting
ROUGH IDLING (CONT'D)
Problem Possible cause Remedy Page
Rough idle or stalls Carburetor problems Perform on-vehicle FU-3
• Id Ie speed incorrect
inspection of carburetor
• Slow jet clogged
• Idle mixture incorrect
• Fuel cut solenoid valve not open
• Fast idle speed setting incorrect
(cold engine)
• Choke system faulty
HAl system faulty Check compression EC-53
Engine overheats Troubleshoot cooling system
CO-2
EGR valve faulty Check EGR valve EC-30
MC valve faulty
Check MC valve EC-26
Incorrect valve clearance Adjust valve clearance
MA-7
Compression low Check compression EM-ll
ENGINE HESITATES/POOR ACCELERATION
Problem Possible cause Remedy Page
Engine hesitates/
Spark plugs faulty Inspect plugs
IG-4
Poor acceleration
Ignition wiring faulty
Inspect wiring
IG-4
Vacuum leaks Repair as necessary
• PCV line
• EGR line
• HAC line
• Intake manifold
• CMH
• MC
Incorrect ignition timing Reset timing IG-l0
Air filter clogged
Check air filter MA-5
Fuel line clogged Check fuel line
Carburetor problems Repair as necessary FU-4
• Float level too low
• Accelerator pump faulty
• Power valve faulty
• Choke valve closed (hot engine)
• Choke system
• Secondary throttle stopper
operation faulty (cold engine)
CMH system faulty (cold engine)
Emission control system problem
• HAl system always on
Check HAl system
EC-53
(hot engine)
• AAP system faulty
Check AAP system EC-61
• EGR system always on
Check EGR system EC-30
(cold engine)
• HAC system faulty
Check HAC system
EC-48
Engine overheats Check cooling system CO-2
Compression low Check compression
EM-ll