S10/T10 P/U 2WD L4-121 2.0L VIN Y 2-bbl (1983)
AIR CLEANER CONNECTOR
EGR VACUUM PIPE LOCATION
EGR Pipe Inspection Procedure
Step 3. Plug port 1 and 4, hook vacuum gage to port 3.
A.
At idle, vacuum should read zero (0).
B.
At off, idle vacuum should read 3-5" Hg. (A weaker signal than seen at port 1 when the throttle is stabbed).
Step 4. Plug ports 1 and 3, hook vacuum gage to port 4.
A.
At idle, vacuum should read zero (0).
B.
At an off idle vacuum throttle position, vacuum should read less than seen at port 3.
C.
Crimp 1-1/4" long hose at EGR valve, vacuum should equal to reading at port 3.
If the engine is not fully warmed up (water temperature 160~F or higher), there will be no signal at port 4.