Jeep Cherokee 1999 Electronic Service Manual page 1019

9 - 2 ENGINE
GEN ERAL I N FORM AT I ON (Cont inue d)
in ch ) dr op is pla ced in t h e cen t er of t h e ga sket con -
t a ct a r ea . Un cu r ed sea la n t m a y be r em oved wit h a
sh op t owel. Com pon en t s sh ou ld be t or qu ed in pla ce
wh ile t h e sea la n t is st ill wet t o t h e t ou ch (wit h in 10
m in u t es). Th e u se of a loca t in g dowel is r ecom -
m en ded du r in g a ssem bly t o pr even t sm ea r in g t h e
m a t er ia l off loca t ion .
Mopa r Ga sket Ma ker sh ou ld be a pplied spa r in gly
t o on e ga sket su r fa ce. Th e sea la n t dia m et er sh ou ld
be 1.00 m m (0.04 in ch ) or less. Be cer t a in t h e m a t e-
r ia l su r r ou n ds ea ch m ou n t in g h ole. E xcess m a t er ia l
ca n ea sily be wiped off. Com pon en t s sh ou ld be
t or qu ed in pla ce wit h in 15 m in u t es. Th e u se of a
loca t in g dowel is r ecom m en ded du r in g a ssem bly t o
pr even t sm ea r in g t h e m a t er ia l off loca t ion .
ENGINE PERFORMANCE
It is im por t a n t t h a t t h e veh icle is oper a t in g t o it s
opt im u m per for m a n ce level t o m a in t a in fu el econ om y
a n d t h e lowest em ission levels. If veh icle is n ot oper-
a t in g t o t h ese st a n da r ds, r efer t o E n gin e Dia gn osis
ou t lin ed in t h is sect ion . Th e followin g pr ocedu r es ca n
a ssist in a ch ievin g t h e pr oper en gin e dia gn osis.
(1) Test cr a n kin g a m per a ge dr a w. Refer t o E lect r i-
ca l Gr ou p 8B, Cold Cr a n kin g Test .
(2) Ch eck in t a ke m a n ifold bolt t or qu e; Refer t o
Gr ou p 11, E xh a u st Syst em a n d In t a ke Ma n ifold.
(3) P er for m cylin der com pr ession t est . Refer t o
Cylin der Com pr ession P r essu r e Test in t h e E n gin e
Dia gn osis a r ea of t h is sect ion .
(4) Clea n or r epla ce spa r k plu gs a s n ecessa r y a n d
a dju st ga p a s specified in E lect r ica l Gr ou p 8D.
Tigh t en t o specifica t ion s.
(5) Test r esist a n ce of spa r k plu g ca bles. Refer t o
E lect r ica l Gr ou p 8D, Spa r k P lu g Ca bles.
(6) In spect t h e pr im a r y wir es. Test coil ou t pu t volt -
a ge a n d pr im a r y r esist a n ce. Repla ce pa r t s a s n eces-
sa r y. Refer t o E lect r ica l Gr ou p 8D, for specifica t ion s.
(7) Test fu el pu m p for pr essu r e. Refer t o Gr ou p 14,
F u el Syst em Specifica t ion s.
(8) Th e a ir filt er elem en t s sh ou ld be r epla ced a s
specified in Lu br ica t ion a n d Ma in t en a n ce, Gr ou p 0.
(9) In spect cr a n kca se ven t ila t ion syst em a s ou t
lin ed in Gr ou p 0, Lu br ica t ion a n d Ma in t en a n ce. F or
em ission con t r ols see Gr ou p 25, E m ission Con t r ols
for ser vice pr ocedu r es.
(10) Roa d t est veh icle a s a fin a l t est .
HONING CYLINDER BORES
Befor e h on in g, st u ff plen t y of clea n sh op t owels
u n der t h e bor es a n d over t h e cr a n ksh a ft t o keep
a br a sive m a t er ia ls fr om en t er in g t h e cr a n ksh a ft
a r ea .
(1) Used ca r efu lly, t h e Cylin der Bor e Sizin g H on e
C-823 equ ipped wit h 220 gr it st on es, is t h e best t ool
for t h is job. In a ddit ion t o degla zin g, it will r edu ce
t a per a n d ou t -of-r ou n d a s well a s r em ovin g ligh t
scu ffin g, scor in g or scr a t ch es. Usu a lly a few st r okes
will clea n u p a bor e a n d m a in t a in t h e r equ ir ed lim -
it s.
CAUTION: DO NOT use rigid type hones to remove
cylinder wall glaze.
(2) Degla zin g of t h e cylin der wa lls m a y be don e if
t h e cylin der bor e is st r a igh t a n d r ou n d. Use a cylin -
der su r fa cin g h on e, H on in g Tool C-3501, equ ipped
wit h 280 gr it st on es (C-3501-3810). 20-60 st r okes,
depen din g on t h e bor e con dit ion , will be su fficien t t o
pr ovide a sa t isfa ct or y su r fa ce. Usin g h on in g oil
C-3501-3880 or a ligh t h on in g oil a va ila ble fr om
m a jor oil dist r ibu t or s.
CAUTION: DO NOT use engine or transmission oil,
mineral spirits or kerosene.
(3) H on in g sh ou ld be don e by m ovin g t h e h on e u p
a n d down fa st en ou gh t o get a cr ossh a t ch pa t t er n .
Th e h on e m a r ks sh ou ld INTE RSE CT a t 50° t o 60°
for pr oper sea t in g of r in gs (F ig. 1).
Fig. 1 Cylinder Bore Crosshatch Pattern
(4) A con t r olled h on e m ot or speed bet ween 200 a n d
300 RP M is n ecessa r y t o obt a in t h e pr oper cr oss-
h a t ch a n gle. Th e n u m ber of u p a n d down st r okes per
m in u t e ca n be r egu la t ed t o get t h e desir ed 50° t o 60°
a n gle. F a st er u p a n d down st r okes in cr ea se t h e cr oss-
h a t ch a n gle.
(5) Aft er h on in g, it is n ecessa r y t h a t t h e block be
clea n ed t o r em ove a ll t r a ces of a br a sive. Use a br u sh
t o wa sh pa r t s wit h a solu t ion of h ot wa t er a n d det er-
gen t . Dr y pa r t s t h or ou gh ly. Use a clea n , wh it e, lin t -
fr ee clot h t o ch eck t h a t t h e bor e is clea n . Oil t h e
bor es a ft er clea n in g t o pr even t r u st in g.
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