Injectoin Timing Check And Adjustment - Isuzu 4BG1 Instruction Manual

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Fig. 37
Fig. 38
(3) Injection Timing Check and Adjustment
Improper injection timing causes serious engine failure such as
blackish exhaust smoke, poor engine output and engine
breakage etc.
In normal servicing, this check and adjustment is unnecessary,
however, it might be necessary in conjunction with a related
works.
Check procedure
1) Bring No. 1 cylinder to the top dead center on the compression
stroke.
Turn the crankshaft pulley clockwise
(viewed
at engine front)
and align the notched line on the crank pulley with the TDC
mark on the timing gear case cover.
Remove the timing check hole cover at the front of injection
pump to check the alignment between the pointer "a" on the
injection pump gear lock plate and the projected area mark "b"
on the timing gear case.
If "a" and "b" are in alignment, the timing is set correctly.
If they are in alignment. No. 1 cylinder is at the TDC on the
compression stroke. If it is in misalignment, recheck with
turning the crankshaft pulley one more turn to repeat the
aforegoing procedure to make sure that it is in alignment.
Next, inspect the crankangle position of the injection starting.
2) Reversely turn the crankshaft pulley counterclockwise viewed at
the engine front about 30° crank angle.
3) Remove No. 1 injection pipe from the engine.
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