Intake Air Bypass Control Thermal Valve Test - Honda EP3 Service Manual

Intake Air Bypass GontrolThermalValve Test
Special Tools Required
Vacuum Pump/Gauge,0 30 in. Hg A973X-041-XXXXX
1 . S t a n t h e e n g i n e . T h e n l e t i t i d l € .
NOTE: The engine coolant temperature must be
b e l o w 1 4 9 ' F ( 6 5 ' C ) .
2 . R e m o v e t h e v a c u u m h o s e ( A ) f r o m t h e i n t a k e a i r
duct, and connect a vacuum pump/gauge to the
nose.
3 . R a i s e a n d l o w e r t h e e n g i n e s p e e d . a n d m a k e s u r e
t h e v a c u u m g a u g e r e a d i n g c h a n g e s a s t h e e n g i n e
speeo cnanges.
lf the vacuum reading does not change, check for
these problems:
. M i s r o u t e d , l e a k i n g , b r o k e n , o r c l o g g e d i n t a k e a i r
bypass control system vacuum lines.
. A cracked or damaged intake air bypass control
t h e r m a l v a l v e .
4 . H o l d t h e e n g i n e a t 3 , 0 0 0 r p m w i t h n o l o a d ( i n
neutral) until the radiator fan comes on, then let it
i d l e .
5 . R a i s e a n d l o w e r t h e e n g i n e s p e e d , a n d m a k e s u r e
the vacuum gauge reading does not change as the
r p m c n a n g e s .
lf the vacuum reading changes, check for these
p r o o r e m s :
. l\4isrouted, leaking, broken, or clogged intake air
bypass control system vacuum lines.
. A cracked or damaged intake air bypass control
t h e r m a l v a l v e .
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