Jeep 1987 Wrangler Workshop Manual page 251

ENGINES
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GENERAL SERVICE AND DIAGNOSIS
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Service Diagnosis—Performance (Continued)
Condition Possible Cause Correction
PING OR SPARK
KNOCK
(Continued)
(7) Sharp edges in combustion
chamber.
(8) E G R Valve not functioning
properly.
(7)
(8)
Grind smooth.
Test E G R System and replace
as necessary.
SURGING (AT
CHU1S1NG TO TOP
S P E E D S )
(1) Low carburetor fuel level.
(2) Low fuel pump pressure or volume.
(1)
(2)
Adjust fuel level.
Replace fuel pump.
(3) Metering rod(s) not adjusted
properly (BBD Model Carburetor).
(3)
Adjust metering rod.
(4) Improper PCV valve air flow.
(4)
Test PCV valve and replace
as necessary.
(5) Air leak into manifold vacuum. (5) Check manifold vacuum and repair
as necessary.
(6) Incorrect spark advance.
(6)
Test and replace as necessary.
(7) Restricted main jet(s).
(7)
Clean main jet(s).
(8) Undersize main jet(s). (8) Replace main jet(s).
(9) Restricted air vents.
(9)
Clean air vents.
(10) Restricted fuel filter.
(10)
Replace fuel filter.
(11) Restricted air cleaner.
(11)
Clean or replace air cleaner filter
element.
(12) E G R valve not functioning
properly.
(12)
Test E G R System and replace
as necessary.
(13) Improper feedback system
operation.
(13)
Refer to Feedback System
Diagnosis.
S E E
I . S .
N
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T
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80652F
B-17