6-12 Chapter 6 Emissions control systems
7.12a EGR system component locations (2.4L engine)
3.OL Engine
7.12b EGR system component locations (XOL engine)
18 To check the therm0 valve, disconnect the green-stnped hose from
the valve (see illustration).
19 Connect the hand-held vacuum pump to the therm0 valve and apply
vacuum (see illustration). If no vacuum can be held, the therm0 valve IS
good.
20 To check the EGR control valve, disconnect the green-stnped hose
from the nipple on the carburetor and connect it to the hand-held vacuum
pump (see illustration).
21 Open the sub-EGR valve (by pulling on it by hand) and apply avacu-
urn to the EGR control valve with the pump.
22 If the idle speed becomes unstable, the EGR valve is operating prop-
erly. If the idle speeds remain the same, the valve
IS
not operating properly
and it should be replaced with a new one.
23 Pull on the sub-H.% valve and check tor smooth operation. It the mr
valve bmds. it should be removed from
its
bore,
cleaned
thoroughly, tub?- 5
cated with a small amount of light 011 and remstalled. If itstlll does not oper-
ate smoothly, replace it with a new one.
Canadian models
yIL=
24 Check all vacuum hoses for cracks and proper mstallatlon.
Etis-
25 Start the engine (it must be completely cool) and run it at idle speed. E.
Touch the underside of the !A% control valve diaphragm and increase the m -~
engine speed from idle to 2500 rpm. Warning: The valve maybe very hot w
- wearagloveorusearag topreventyourhand from burns. Nomovement
-
zz
of the diaphragm should be felt. II movement is felt, which means that the
fGR valve is opening:check thegreen-stripedvacuum hose to make surj e:
rrisn’rclogged. If the hose
IS
clear, the thermal valve is most likelydefectiie m
we
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