Pontiac Fiero 1988 Service Manual page 275

64 ENGINE GENERAL INFORMATION
'j Bent connecting rod.
HbAVY KNOCK HOT WITH TORQUE APPLIED
Broken balancer, or pulley hub. Replace parts as
necessary.
Loose torque converter bolts.
Accessory belts too tight or nicked. Replace
and/or tension to specs as necessary.
Exhaust system grounded. Reposition as
necessary.
Flywheel cracked.
Excessive main bearing clearance. Replace as
necessary.
Excessive rod bearing clearance. Replace as
necessary.
LIGHT KNOCK HOT
Detonation or spark knock. Check operation of •
EST or ESC (See Section 6D or 6E). Check •
engine timing and fuel quality.
Loose torque converter bolts.
Exhaust leak at manifold. Tighten bolts and/or
replace gasket.
Excessive rod bearing clearance. Replace
bearings as necessary.
KNOCKS ON INITIAL S T A R T U P BUT ONLY LASTS A FEW SECONDS
Noisy mechanical fuel pump. Replace pump.
Improper oil viscosity. Install proper oil viscosity
for expected temperatures. See Owner's Manual.
Hydraulic lifter bleed down. Clean, test and
replace as necessary.
When the engine is stopped, some valves
will be open. Spring pressure against lifters
will tend to bleed lifter down. Attempts to
repair should be made only if the problem
is consistent.
Excessive crankshaft end clearance. Replace
crankshaft thrust bearing.
Excessive front main bearing clearance. Replace
worn parts.
KNOCKS AT IDLE HOT
Loose or worn drive belts. Tension and/or
replace as necessary.
A/C Compressor or generator bearing. Replace
as necessary.
Noisy mechanical fuel pump. Replace pump.
Valve train. Replace parts as necessary.
Improper oil viscosity. Install proper viscosity oil
for expected temperature. See Owner's Manual.
Excessive piston pin clearance. Ream and install
oversize pins. (VIN R and 2) or replace piston
and pin.
Connecting rod alignment. Check and replace
rods as necessary.
Insufficient piston to bore clearance. Hone bore
and fit new piston.
Loose crankshaft balancer. Torque and/or
replace worn parts.
Piston pin offset to wrong side. Install correct
piston.
ENGINE OVERHEATS
Coolant system leak, oil cooler system leak, or
coolant recovery system not operating. Check for
leaks and correct as required. Check coolant
recovery tank, hose and radiator cap.
2. Belt slipping or damaged. Replace tensioner, or
belt, as required.
3. Thermostat stuck closed. Check and replace if
required.
4. Electrical cooling fan operation. See the
ELECTRICAL TROUBLESHOOTING
MANUAL.
5. Head gasket leaking. Check and repair as
required.