Pump-to-engine timing is extremely critical. Pump timing that is off by only a few crankshaft degrees will cause:
1. Poor performance – starting and power.
2. Excessive smoke and emissions.
3. Poor fuel economy.
Engine pump timing begins with the timing of the fuel injection pump drive gear to the camshaft gear.
The first step is the location of TDC of the compression stroke for Cylinder No. 1.
Then, depending on the engine configuration, a letter on the gear may need to be aligned with the mark on the
camshaft gear.
This table must be used to make sure of proper fuel injection pump-to-engine timing. The critical parts list
(CPL) number from the engine data plate and the Control Parts List Manual, Bulletin No. 3379133-20, must be used
to determine whether or not the engine is certified, and if so, what year and regulating agency (EPA or CARB).
Given this information, use the following table to determine which letter on the fuel injection pump drive gear is
aligned with the camshaft gear.
NOTE: Timing mark alignment is not required for the Nip pondenso EP-9 or Bosch P7100 drive gear.
To verify that the fuel injection pump is timed correctly, first check the alignment marks on the pump flange and
gear housing.
NOTE: 1 mm of rotation past the timing mark will advance or retard (depending on direction of rotation) the pumptiming by 1 degree.
The Lucas CAV DPA, DPS, Stanadyne DB4, and the Bosch VE fuel injection pumps all have a provision for
locking the pump shaft at a position corresponding to top-dead-center for Cylinder No. 1. New and reconditioned fuel injection pumps should be received with the shafts located in this position.
At the point of injection the key way of the shaft will align with the delivery valve receiving the injection, and the
illustrated hash mark on the seal housing.
NOTE: The illustrated mark is for reference only and should not be used for setting the fuel injection pump timing.
The number one cylinder delivery valve is marked as illustrated.
The engine is equipped with an engine timing pin to locate TDC for Cylinder No. 1.
Caution: If the timing pin is incorrectly located on the gear housing, the timing procedure will not ensure that
the pump is timed correctly.
After precisely locating TDC for Cylinder No. 1, the factory positions the timing pin assembly to the gear housing
using the timing pin and the hole in the camshaft gear. If the gear housing or timing pin assembly are removed, the
same precision is required to relocate it. Refer to Procedure (7-20).
If the timing pin assembly is incorrectly located, reposition the timing pin. Refer to Procedure (7-20).
The flange of a replacem ent pum p m ust be marked to align with the mark on the gear housing after instal
lation.
During production, after the locked pump is fitted to the engine with Cylinder No. 1 at TDC, a mark is stamped on
the gear housing and the pump flange. Thereafter, when these marks are aligned, the pump is correctly timed to
the engine.
NOTE: The marks on the gear housing and the pump flange are unique to each engine.
A special indicator can be used to measure the position of the Robert Bosch VE fuel injection pump plunger to
check pump timing.
Refer to Timing Check – (Bosch VE Pump) – Procedure (5-36).
Stanadyne DB4 Fuel Injection Pump Timing
Clean all debris from around the fuel injection pump timing window cover.
Remove the fuel injection pump timing cover.
Rotate the fuel injection pump drive shaft in the direction of pump rotation to align the timing line on the weight
retainer hub with the line on the cam ring.
Position the fuel injection drive shaft locking key plate in the locked position. Turn the locking screw in until contact
is made with the drive shaft.
Torque Value: 11.9 N«m [105 in-lb]
Verify the timing marks are aligned after lock timed.
Install the fuel injection pump timing cover.
