Electra V6-260 4.3L DSL (1984)
Diesel MFI Pump: Adjustments
Injection Pump Timing
Refer to Diesel Engine Performance Specifications chart for specified injection pump timing.
LESS TIMING METER
1.
The mark on the injection pump adapter must be aligned with the mark on the injection pump flange.
2.
To adjust:
a. Loosen injection pump retaining nuts with tool J-26987.
b. Align mark on injection pump flange with mark on the injection pump adapter.
c. Torque injection pump retaining nuts to 35 ft. lbs.
WITH TIMING METER J-33075
Certain engine malfunctions can cause inaccurate timing readings. Engine malfunctions should be corrected before adjusting pump timing.
The marks on the pump and pump adapter will normally be aligned within .050 inch.
1.
Place transmission in Park, apply brake and block drive wheels.
2.
Start engine and allow to reach normal operating temperature, then shut engine off.
3.
Remove air cleaner assembly, install cover J-26996-1, then disconnect EGR valve hose.
4.
Clean dirt from engine probe holder and crankshaft balancer rim.
5.
Clean lens on both ends of glow plug probe. Look through probe to ensure that it is clean.
6.
Remove glow plug from No. 1 cylinder. Insert glow plug probe into glow plug opening and torque probe to 8 ft. lbs.
7.
Set timing meter selector to A, then connect meter battery leads.
8.
Disconnect generator two lead connector, then start engine and adjust idle speed to specifications.
9.
Observe timing meter, wait approximately two minutes, then observe timing meter again. When meter stabilizes, compare timing reading to
specifications. If timing is as specified, proceed to step 14. If timing is not as specified, proceed to next step.
10.
Turn engine off and note relative position of marks on pump flange and adapter.
11.
Loosen nuts or bolts holding pump to adapter, then rotate pump to the left (advance) or right (retard) as necessary. Torque retaining nuts or bolts
to 35 ft. lbs. Move pump gradually when adjusting timing. The width of the adapter timing mark is equal to approximately 2/3°.
12.
Start engine and recheck timing. Reset timing, if necessary.
13.
Readjust curb and fast idle speeds.
14.
Disconnect timing meter and install removed glow plug. Torque glow plug to 12 ft. lbs.
15.
Connect generator two lead connector, install air cleaner assembly and reconnect EGR valve hose.
The timing marks on the injection pump and adapter should be close to being lined up after timing the engine. If they are not, and the engine
still exhibits poor performance, the timing may still be incorrect. A misfiring cylinder can result in incorrect timing. When this occurs, it is
necessary that timing be checked in an alternate cylinder. Timing can be checked in cylinders 1 or 4. If a difference exists between cylinders, try
both positions to determine which timing performs best.
If the engine continues to run poorly and excessive exhaust smoke is evident, check the housing pressure cold advance for proper operation. If the
advance is operating properly, a stuck or frozen injection pump advance piston may be at fault. This piston can be checked by pushing in on the bottom
of the face cam lever on the right side of the injection pump. If the piston is free, the timing will retard and cause the engine to run roughly. If no change
is evident, the piston is sticking and must be repaired.
