Engine - Surging, Bucking and Spark Knock

84chrysler5

Models

1985 5th Avenue, Diplomat & Gran Fury W/318-2V Engine, Federal & California Emissions W/Carburetors 4288576 or 4288563


Subject


Road Load Surge, Bucking Surge on Deceleration or Coasting & Spark Knock


Index

FUEL


Date

December 3, 1984


No.

14-64-84
SYMPTOM/CONDITION

A condition of surge and bucking may exist on subject model vehicles just after cresting a hill while driving at steady speeds above 45 mph.

Bucking may also be detected when lightly throttling back (floating down) at speeds above 45 mph.

In addition, a spark knock condition may also be exhibited during acceleration, but it is unrelated to the bucking or surge symptom described above.

PARTS REOUIRED

Driveability Package PN 4342943

Consists of:

1 - Vacuum Bleed-Off Valve PN 4306924
1 - 4-Second Vacuum Delay Valve PN 4173433
1 - 3/16" Vacuum Tee PN 4104172
1 - Hose Routing Label NPN

Must be ordered separately:

1 - Carburetor PN 4288565
1 - Authorized Modification Label PN 4275086

Installation Procedure

1.. Remove original carburetor and install service Carburetor PN
4288565.

2. Cut three 1-1/2" and one 6" pieces of 3/16" Vacuum Hose PN 4105167 (serviced in bulk stock 50' rolls).

FIGURE 1:

3. Referring to Figure 1, assemble the overlay vacuum hose harness as illustrated.

4. Locate the dual vacuum solenoid assembly on engine compartment bulkhead (firewall).
Remove the moulded white rubber 90~ connector from the driver side solenoid and insert the orange end of vacuum delay valve in the white 90~ connector (Figure 1).

5. Connect the 1-1/2" hose attached to tee on nipple of solenoid from which the white connector was just removed in Step 4 above.

6. Remove the 3/16" vacuum nipple cap from manifold vacuum tree located on intake manifold to the rear of carburetor.

Attach the 6" hose on vacuum bleed-off valve to the open 3/16" vacuum tree nipple (Figure 1).

7. Disconnect and plug the vacuum hose at the ESA module.

Start engine and allow to fully warm up so engine will run at curb idle. Reset basic timing to 3~ BTDC. Reconnect vacuum hose to ESA module.

8. Clean the existing hose routing label surface and apply Service Hose Routing Label.

FIGURE 2:

9. Type information on Authorized Modification Label, PN 4275086, as illustrated in Figure 2.

NOTE: 1985 318-2V PASSENGER CARS WITH CALIFORNIA EMISSION SYSTEM ONLY

IF A 3-1/2" VACUUM REDUCER, PN 4091910, HAS BEEN INSTALLED IN THE ESA/EFC MODULE VACUUM HOSE FOR A PRIOR SPARK KNOCK CONDITION, IT MUST BE REMOVED.
This Bulletin is being released in advance of Parts availability. The parts listed in this Bulletin will be available in mid December, 1984.


POLICY: Reimbursable within the provisions of the warranty

TIME ALLOWANCE:
Labor Operation No. 14-64-84-90............................................... 0.8

FAILURE CODE: AM - Authorized modification