Sentra Wagon FWD L4-1597cc 1.6L SOHC (GA16i) (1989)
Deceleration Valve: Testing and Inspection
Fig. 176 A/B Valve Test
1.
Start and warm the engine to operating temperature.
2.
Remove the air cleaner lid and filter.
3.
Place your finger over the A/B valve inlet.
4.
Run the engine at 3000 RPM and release the throttle quickly.
There should be strong vacuum.
If not proceed to step #5.
5.
Check for vacuum leak in A/B source hose.
If no leaks are found replace A/B valve.