Daewoo G424 Gasoline, Service Manual

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G424 Service Manual Adjustment and Troubleshooting 172
Troubleshooting
Engine Performance
Symptom Cause
1. Poor engine idle. A. Clogged air breather.
B. Improper idle-fuel mixture adjustment.
C. Cap or spark-plug wires arcing.
D. Low grade fuel.
E. Incorrect ignition timing.
F. Spark plugs (fouled, burned, cracked porcelain).
G. Spark plug wires broken or faulty insulation.
H. Defective coil.
I. Cracked or dirty distributor cap.
J. Dirty carburetor.
K. Leak at intake manifold or carburetor base.
L. Low compression. (Check for blown head gasket).
M. Loose or worn distributor.
N. Head gasket, exhaust manifold, cracked head or valve seat.
2. Poor engine acceleration. A. Idle mixture screw.
B. Incorrect ignition timing.
C. Incorrect distributor advance curve.
D. Cracked or dirty distributor cap or rotor.
E. Vacuum leak on the intake manifold or carburetor base.
F. Spark plugs (fouled, burned, wrong heat range, cracked porcelain).
G. Dirty carburetor.
H. Low compression.
Engine Starting Problems
The following information will help to locate the starting problem:
1. Determine which engine system is causing the problem. To make an engine run, basic components - fuel,
spark (ignition) and compression - are required. If all three components are present, the engine should run. If
any one of the three is missing, weak or arriving at the wrong time, the engine will not run.
2. Determine if there is fuel present.
3. Check ignition system operation. Using appropriate spark tester, check for spark at coil and at each spark plug.
If there is a spark at the spark plug wires, remove the spark plugs and make sure they are the correct type and
heat range, and not fouled or burned.
4. Run a compression check on the engine to make sure it is mechanically sound.