Chrysler RAM TRUCK 2500 1994 Service Manual page 731

9 - 10 ENGINES •
SERVICE DIAGNOSIS (DIESEL ENGINE) - PERFORMANCE (CONT.)
mmmnm
POSSIBLE CAUSES
CORRECTION
ROUGH IDLE
(IRREGULARLY FIRING
OR ENGINE SHAKING)
(Cont'd)
High pressure fuel leaks.
A i r in t h e fuel s y s t e m .
Correct leaks in t h e high pressure lines, fittings o r d e l i v e r y
valves.
Bleed t h e fuel s y s t e m a n d e l i m i n a t e t h e source of t h e air.
Sticking n e e d l e v a l v e i n a n
injector.
Check a n d replace t h e injector w i t h the s t i c k i n g n e e d l e v a l v e .
ENGINE RUNS ROUGH
OR MISFIRING
Fuel injection lines l e a k i n g . Correct leaks in t h e high pressure lines, fittings, injector sealing
w a s h e r s o r d e l i v e r y valves.
A i r in t h e fuel o r t h e fuel
supply is i n a d e q u a t e .
Check t h e f l o w t h r o u g h t h e filter a n d b l e e d t h e s y s t e m . Locate
a n d e l i m i n a t e t h e a i r source.
C o n t a m i n a t e d fuel.
Verify b y o p e r a t i n g t h e e n g i n e w i t h clean fuel f r o m a t e m p o r a r y
supply t a n k . Check f o r presence of gasoline. Replace f u e l / w a t e r
s e p a r a t o r filter.
Incorrect v a l v e adjustment.
Check f o r a b e n t push r o d a n d adjust valves. Replace push r o d ,
if necessary.
Injection p u m p t i m i n g incorrect. C h e c k / t i m e p u m p (refer t o G r o u p 14, Fuel System).
I m p r o p e r l y o p e r a t i n g injectors. Replace i n o p e r a t i v e injectors.
Defective injection p u m p
( d e l i v e r y v a l v e s ) .
Repair or replace injection pump.
Camshaft o u t of t i m e . C h e c k / c o r r e c t g e a r t r a i n t i m i n g a l i g n m e n t .
D a m a g e d camshaft o r t a p p e t s . Inspect camshaft v a l v e lift. Replace camshaft a n d t a p p e t s .
ENGINE RPM WILL N O T
REACH RATED SPEED
Engine o v e r l o a d e d . Verify h i g h idle s p e e d w i t h o u t l o a d . I n v e s t i g a t e o p e r a t i o n t o b e
sure correct g e a r is b e i n g used.
I m p r o p e r l y o p e r a t i n g
t a c h o m e t e r .
Verify e n g i n e s p e e d w i t h h a n d t a c h o m e t e r — c o r r e c t as r e q u i r e d .
T h r o t t l e l i n k a g e w o r n o r
incorrectly adjusted.
Adjust l i n k a g e for stop-to-stop fuel c o n t r o l l e v e r t r a v e l . Replace
l i n k a g e if necessary.
Partially e n g a g e d mechanical
s h u t d o w n l e v e r .
A d j u s t a n d place s h u t d o w n l e v e r in t h e r u n p o s i t i o n .
I n a d e q u a t e fuel s u p p l y .
Air-fuel control leak.
I m p r o p e r l y o p e r a t i n g injection
p u m p .
Check t h e fuel f l o w t h r o u g h t h e s y s t e m t o locate t h e reason for
i n a d e q u a t e fuel s u p p l y — c o r r e c t as r e q u i r e d .
Check and repair leak. Check AFC tubing for obstruction.
Repair or replace injection pump.
LOW POWER Fuel c o n t r o l l e v e r not m o v i n g t o
full t h r o t t l e .
C h e c k / c o r r e c t for stop-to-stop t r a v e l .
S h u t d o w n l e v e r
p a r t i a l l y e n g a g e d .
Check t o see if t h e s h u t d o w n l e v e r is i n r u n p o s i t i o n .
High o i l l e v e l . C h e c k / c o r r e c t o i l l e v e l .
Engine o v e r l o a d e d . Check f o r a d d e d l o a d i n g f r o m accessories o r d r i v e n units, b r a k e s
d r a g g i n g a n d o t h e r changes i n v e h i c l e l o a d i n g . R e p a i r / r e p l a c e as
n e e d e d .
J9409-111