Engine Performance Diagnosis - Pontiac TRANS AM 1977 Service Manual

ENGINE 6-5
ENGINE PERFORMANCE DIAGNOSIS
A. Dieseling
1. Make visual checks of the following for
sticking.
a. Carburetor, choke, and throttle linkage
b. Fast idle cam
See cleaning, inspection, and adjustment of
carburetor, Section 6C.
2. Check and reset ignition timing, idle,
rpm and check idle solenoid for proper
operation. Refer to emission label.
3. Remove carbon with top engine cleaner.
Follow instructions on can.
If condition still exists, suggest that owner
try different gasoline.
B. Detonation 1. Check for obvious overheating problems.
a. Low coolant
b. Loose fan belt
c. Restricted air flow, etc.
2. Check ignition timing per emission control
information label.
NOTE: If timing is too early
-
speed up engine
to see if timing mark moves. If not, check
for stuck mechanical advance. Refer to
Section 6D. Repair as necessary and recheck
timing.
3. Remove carbon with top engine cleaner.
Follow instructions on can. If condition
still exists, suggest that owner try different
gasoline.