Page 327 of 1395
Troubleshooting Flowchart
- The MIL has been rePorted on- DTC P0171 andlot P0172 are
stored,
Check the lu6l pressuro regulator
and tusl relum PiPe.ls the lLrel pressure too high
Check lhe Primaty HO2S:1. Start the engine. Hold the
engine at 3,000 rpm with no
load (in Park ot neutral) until
the radiator fan comes on
2. Check the Primary HO2S(Sensor 1) outPut with the
scan tool.
Check lh€ fuel pumP. fuel faedpipe. fuel fiher, and luel Prossurc.eguhior.
Does it stay at lessthan 0.3 V
or more than 0.6 V?
Check for a sticking or leaking
EVAP purge control solenoid
With a vacuum pump, aPPIY vacu
um to the EVAP Purge control
solenoid valve from the intake
manifold side.
Does it hold vacuum?
Check th6 valve clearanc€s and
adjust il necessary. It the valv€
clearances are OK, replace the
fuel iniectors.
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Page 328 of 1395

PGM-FI System
Random Misfire
lF()gool", tftod-' and some or lpiogol throughTo3oti
The scan tool indicates Diagnostic Trouble Code (DTC)
P0300*,, P1300*1 and some of po30t - pO3O4; Randommisfire.
Descriotion
Misfire detection is accomplished by monitoring the crankshaft speed with the crankshaft speed fluctuation (cKF) sensorwhich is attached to the crankshaft.lfmisfiring strong enough to damage the catalyst is detected, the MIL will blink during the time of its occurrence, and DTcP0300*' , P1300*1 and some of DTCs P03ol through P0304 will be stored. Then, after misfire has ceased, the MtL will comeon,
lf misfiring that increases emissions is detected during two consecutive driving cycles, the MIL will come on, and DTcand some of DTCS p0301 through p0304 wi
be stored.NOTE: lf some of the DTCS listed below are stored at the same time as a misfire DTc, troubleshoot those DTcs first. thentroubleshoot the misfire DTC.
P0106, P]128, P1'129; MAp sensorP0171. P0172; Fuet metering
P0505: ldle Control Svstem
P1336, P1337; CKF sensor
P1361, P1362: TDC sensor
Pl381. Pl382: CYP sensor
P1508: IAC valve *1:,97 model*2: '98 - 00 models
Possiblo Caus€
. Fuel pump insufficient fuel pressure, amountofflow. Fuel line clogging. blockage, leakage. Fuel filter clogginga Fuel pressure regulator stuck open. Distributormalfunction
. lgnition coil wire open, leakage. lgnition control module malfunction. Valves carbon deposita Compression lowa Fuel does not meet Owner's Manual spec., lack offuel
Troubleshooting
By test-driving, determine the conditions during which misfire occurs. Depending on these conditions, test in the orderdescribed in the table below.
Possible cause
[ ;;;;- -....
Crankshaft
speed fluctuation
sensor
Fuel
pressureDistributor and
lgnition wirestcMValve
Clearance
Conditionsection 611-178section 23section 23section 6
Only low rpm and load,6)o
Only acceleratingooo
Only high rpm and loado@,a'@
Not specificationG\o@o@
NOTE: lf misfire doesn't recur, some possible causes are fuel that doesn't meet owner's manual spec, lack of fuel, carbondeposits on spark plu9, etc.
11-126
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Page 375 of 1395
'97 model:
Check all hose clamps, and retighten if necessary.
FUELFILTER
/\
{"2
,"1<,, I___--tJ
B
FUEL TUBE/OUICK-CONNECTFITTINGS
EVAPORATIVEEMISSION {EVAP}CONTBOLCANISTER
'^s
,4\-') |Ift q'l I
/'------/
/B,To FUELPRESSUREREGULATOR
10-14mm(0.39 - 0.55 inl
(cont'd)
11-173
Clamp in the middle
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Page 376 of 1395
Fuel Supply System
Fuel Lines (confd)
'98 - (X) models:
Check all hose clamps, and retighten if necessary.
SASEGASKETReplace.
FUELFILTER
To FUELPRESSUREREGULATOR
10-14mm(0.39 - 0.ss in)
Clamp in the middle
11-174
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Page 380 of 1395

Fuel Supply System
System Description
The fuel supply system consists of a fuel tank, in-tank
high-pressure fuel pump. PGM-Fl main relay, fuel filter,
fuel pressure regulator, fuel injectors, and fuel delivery
and return lines. This system delivers pressure-regulat-
ed fuel to the fuel injectors and cuts the fuel delivery
when the engine is not running.
Fuel Pressure
Relieving
Before disconnecting fuel pipes or hoses, release pres-
sure from the system by loosening the 12 mm banjo
bolt on the too of the fuel filter.
Do not smoke while working on the fuel system.
Ke€p open flames or sparks away from your work
area,
Be sure to relieve fuel pressure while the ignition
switch is off.
Write down the frequencies for the radio's preset
buttons.
Disconnect the battery negative cable from the bat-
tery negative terminal.
Remove the fuel fill cap.
Use a box end wrench on the 12 mm banjo bolt at
the fuel filter while holding the fuel filter with anoth-
er wrench.
Place a rag or shop towel over the '12 mm banjo bolt.
Slowly loosen the 12 mm banjo bolt one complete
rurn 12 mm BANJoBOLT
1.
SHOP TOWEL
NOTE: Replace the washers whenever the 12 mm
banio bolt is loosened or removed.
11-178
Inspection
1, Relieve fuel pressure.
2. Remove the 12 mm banjo bolt on the fuel filter while
holding the fuel filter with another wrench. Attach
the 12 mm fuel pressure adapter bolt and the special
tool.
FUEL PRESSUREREGULATON
FUELPRESSUREGAUGE07406 - 0040001
The illustration shows'97 - 98 models,'99 - 00 models are similar.
Start the engine. Measure the fuel pressure with the
engine idling and the vacuum hose of the fuel pres-
sure regulator disconnected from the fuel pressure
regulator and pinched. lf the engine will not start,
turn the ignition switch on (ll), wait for two seconds,
turn it off, then back on again and read the fuel
pressure.
Pressure should be:'97 - 98 mod€ls:
260 -31O kPa 12.7 - 3.2 kgf/cm,, 38 - 46 psil'99 - 0O models:
270 - 32O kPa Q.A - 3.2 kgf/cm' , ifo - /U psil
Reconnect vacuum hose to the fuel pressure regulator.
Prgs3ure should be:'97 - 98 models:
210 - 25O kPa 12.1- 2.6 kgf/cm' , 30 - 37 psi)'99 - 00 models:
22O -26iJ kPa 12.2 - 2.7 kgt/cm' , 31 - 38 psi)
lf the fuel pressure is not as specified, first check the
fuel pump (see page 11- 183). lf the fuel pump is OK,
check the following:
. lf the fuel pressure is higher than specified,
inspect for:- Pinched or clogged fuel return hose or line.- Faulty fuel pressure regulator (see page 11-
181).
. lf the fuel pressure is lower than specified. inspect
for:- Clogged fuel filter.- Faulty fuel pressure regulator (see page 11-
1811.- Fuel line leakage.
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Page 381 of 1395
Fuel Injectors
R6placomoni
1. Relieve the fuel pressure (see page 11-178).
2. Remove the resonato. chamber ('99 - 00 models).
O.RINGBeplace.
Disconnect the connectors from the fuel injectors, and disconnect the IAT sensor 2P connector ('97 - 98 models) and
EVAP purge control solenoid valve 2P conn€ctor ('97 - 98 models),
Disconnect the PCV valve and the vacuum hose from the fuel pressure regulator.
Place a shop towel over the fuel return hose, then disconnect it from the fuel pressure regulator.
Remove the retainer nuts on the fuel rail.
Disconnect the fuel rail.
7, Remove the fuel injectors from the intake manifold.
'97 - 98 model3:
EVAP PURGE CONTROLSOLENOID VALVE 2P CONNECTORIAT SENSOR
FUEL PULSATION2P CONNECTOR
12 N.m{1.2 kgt'm,8.7 tbtft)
FUELPRESSUREREGULATOR
O.RING
FUELPRESSUREREGULATOR
CUSHION
O.RINGReplace.
CUSHIONRINGReplace.
SEALRINGReplace.
Replace.
SEALRINGReplace.
S
11-179
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Page 382 of 1395

Fuel Supply System
Fuel Injectors {cont'dl
8. Slide new cushion rings onto the fuel injectors.
9, Coat newO-ringswith clean engine oil,and putthem onthefuel iniectors.
'10. lnsert the fuel injectors into the fuel rail first.
11. Coatnewseal ringswithclean engineoil,and press them into the intake manifold
12. To prevent damage to the O-rings, install the fuel injectors in the fuel rail first, then install them in the intake mani-
fold.
FUEL RAIL
The ill!stration shows'97 -98 models,'99 - 00 modelsare similar.
13. lnstall and tighten the retainer nuts.
14. Connect the vacuum hoses and fuel return hose to the fuel pressure regulator.
15. Connect the PCV valve.
16. Connect the connectors to the fuel injectors, the IAT sensor ('97 - 98 models), and the EVAP purge control solenoid
valve {'97 - 98 models).
Coat a new O-ring with clean engine oil, and install the resonator chamber ('99 - 00 models).
Turn the ignition switch ON (ll), but do not operate the starter. After the fuel pump runs for approximately two seconds,
the fuef pressure in the fuel line rises. Repeat this two or three times, then check whether there is any fuel leakage.
11.
18.
1 1-180
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Page 383 of 1395

Fuel Pressure Regulator
Tesiing
1. Attach the special tool and the 12 mm fuel pressure
adapter bolt to the fuel filter (see page 1l-178)
2. Start the engine.
Prasgure should be:'97 - 98 models;
260 - 310 kPa (2.7 - 3.2 kgl/cm' ,38 -,16 psi)'9!t - 00 models:
27O - 32o kPa l2-8 - 3.3 kgf/cm' , 40 - /l7 psil
(with the lugl pressure rsgulator vacuum hose dis-
connested and pinched)
FUELPRESSUREGAUGE07406 - 0040001
FUEL PRESSURENEGULATOR
The illustration shows'97 - 98 models,'99 -00 modelsare similar.
Reconnect the vacuum hose to the fuel pressure
regulalor.
Check that the fuel pressure rises when the vacuum
hose from the fuel pressure regulator is disconnect-
ed agarn.
lf the fuel pressure did not rise, replace the fuel
pressure regulator.
4.
CLAMP
Replacement
'1. Place a shop towel under the fuel pressure regula-
tor, then relieve fuel pressure (see page 11-1781.
2. Disconnect the vacuum hose and fuel return hose.
3. Remove the two 6 mm retainer bolts and the fuel
pressure reguralor.
12 N.m(1.2 kgf.m,8.7 tbf.ft)
The illustration shows'97 - 98 models, '99 00 models
are similar.
Apply clean engine oil to a new O-ring. and carefully
install it into its proper position.
Install the fuel pressure regulator in the reverse
order of removal,
Replace.
1 1-181
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