G420E/G424E
Tier
LP Engine
Test And Adjustments
84
7.
After you have completed setting the distributor
alignment you will need to adjust the VR sensor
used by the SECM for speed reference. This
sensor is mounted near the crankshaft pulley
wheel (Figure G6).
8.
Rotate the crankshaft pulley so that one of the
gear teeth on the timing wheel aligns in the center
of the VR sensor (Figure G7).
9.
Using a feeler gauge (Figure G8), loosen the
sensor retaining bolts and adjust the gap between
the sensor and the gear tooth from 1.25mm to
1.5mm. Re-tighten the sensor retaining bolts
when complete.
10.
Rotate the crankshaft pulley 180 degrees and
align a timing gear tooth in the center of the VR
sensor pickup as you did in step 8. Verify that the
sensor gap is still within 1.25mm to 1.5mm. This
step is to check timing gear run out and insures
proper speed signal amplitude.
11.
If the VR sensor gap is not within the specification
repeat steps 9 & 10 and continue adjusting the
sensor gap until you are within tolerance. This
completes setting ignition timing and sets the
center of the SECM ignition control range at 15
degrees BTDC.
Figure G6
Figure G8
Figure G7
