Engine - Poor Performance/Spark Knock/Exhaust Backfire
Article No.88-20-20
09/23/88
^ PERFORMANCE POOR - 6.1L, 7.0L AND 7.5L 4V ENGINES
^ SPARK KNOCK - 6.1L, 7.0L AND 7.5L 4V ENGINES
^ BACKFIRE - 6.1L, 7.0L AND 7.5L 4V ENGINES
LIGHT TRUCK:
1979-87 E AND F-SERIES
ISSUE:
Poor performance, spark knock and exhaust backfire may be caused by a burned out or blown out EGR spacer-to-intake manifold gasket. The damaged gasket causes exhaust gas and intake manifold vacuum leaks which results in one or all of the above driveability conditions.
ACTION:
Install a new EGR spacer-to-intake manifold gasket that has long life durability under high heat conditions. Refer to the following procedure for service details.
1. Remove the air cleaner.
2. Remove the throttle rod from the throttle lever on 6.1L and 7.0L engines or the throttle cable on 7.5L engines.
3. Disconnect the choke control cable on 6.1L and 7.0L engines only.
4. Disconnect the hand ihrottle control cable on 6.1L and 7.0L engines only.
5. Disconnect and label the vacuum hoses for the distributor and EGR valve. Also disconnect the vacuum hose at the governor on 6.1L and 7.0L engines only.
6. Disconnect the PCV hose.
7. Disconnect the carburetor fuel line.
8. Disconnect the governor electrical connector on 6.1L and 7.0L engines only.
9. Remove the carburetor retaining nuts and lock washers.
10. Remove the carburetor and EGR spacer from the intake manifold.
11. Remove the EGR spacer-to-intake manifold gasket and the carburetor-to-EGR spacer gasket and throw them away, Figure 14.
12. Thoroughly clean gasket mating surfaces and install a new service EGR spacer-to-intake manifold gasket, (E8TZ-9447-A) and carburetor-to-EGR spacer gasket, (E5HZ-9C477-B).
13. Reverse Steps 1 through 11 for assembly.
14. Adjust the engine idle speed.
15. Adjust the primary and secondary fuel levels and idle fuel mixture.
OTHER APPLICABLE ARTICLES:
None
WARRANTY STATUS:
Eligible Under Emissions Warranty Coverage
OPERATION:
882020A
TIME:
1.1 Hrs.
DLR. CODING:
Basic Part No. 9447
Condition Code: 74