Hard Starting

SYMPTOM DESCRIPTION:
Engine cranks OK, but does not start immediately. Will eventually start and run, but may die shortly after.



SYSTEM OR COMPONENT TO CHECK ACTION

COMPUTER INPUTS/OUTPUTS CHECK: ^ COOLANT TEMPERATURE SENSOR (CTS)
Using a "Scan" tool compare coolant temperature
with ambient temperature on a cold engine.
If coolant temperature reading is 5 degrees
more than or less than ambient air temperature
on a cold engine, check for high resistance in
coolant sensor circuit or sensor itself.
Compare resistance value to the
"Diagnostic Aids" chart in
DIAGNOSTIC CHARTS/TROUBLE CODE CHARTS/CODE 15
^ THROTTLE POSITION SENSOR (TPS)
If a sticking throttle shaft or binding linkage
causes a high TPS voltage (open throttle
indication), the ECM/PCM will not control idle.
Monitoring TPS voltage, a "Scan" tool and/or
voltmeter should read less than 1.25 volts
with throttle closed.
^ IDLE AIR CONTROL (IAC).
Refer to DIAGNOSTIC CHARTS/COMPONENT TESTING
(C-CHARTS) and A-CHARTS.
^ No crank signal.
^ PROM/MEM-CAL updates. Refer to
COMPUTERIZED ENGINE CONTROLS/PROM I.D.).




FUEL NOTE: ^ Fuel pump relay operation.
Pump should turn "ON" for 2 seconds when
ignition is turned "ON." Use CHART A-5 in
DIAGNOSTIC CHARTS/A-CHARTS.
^ FUEL PRESSURE: use CHART A-7 in
DIAGNOSTIC CHARTS/A-CHARTS
^ WATER CONTAMINATED FUEL
^ FAULTY IN-TANK FUEL PUMP CHECK VALVE:
This could allow the fuel in the lines to drain
back to the tank after the engine is stopped.
To check for this condition:
1. Ignition "OFF."
2. Disconnect fuel line at the filter.
3. Remove the tank filler cap.
4. Connect a radiator test pump to the fuel line
and apply 103 kPa (15 psi) pressure.
If the pressure will hold for 60 seconds,
the check valve is OK.
^ FUEL PUMP RELAY - Connect test light between
fuel pump "test" terminal and ground.
Light should be "ON" for 2 seconds
following ignition "ON." If not, refer to
DIAGNOSTIC CHARTS/TROUBLE CODE CHARTS/CODE 54








IGNITION CHECK: ^ Proper ignition voltage output with
spark tester J 26792 or equivalent (ST-125).
^ Spark plugs, wet plugs, cracks, wear,
improper gap, burned electrodes or
heavy deposits.
^ Bare and shorted wires.
^ Loose DIS module connections. If misfiring, cross
firing or cutting out under load or at idle, see
COMPONENT TESTING (C-CHARTS).
^ Moisture in distributor cap.
^ Worn distributor shaft.
^ Pickup coil connections.
NOTE: If engine starts, but then immediately stalls,
disconnect the set timing connector. If engine
then starts, and runs OK, replace distributor
pickup coil. For DIS, remove the crankshaft sensor and check for
improper resistance or faulty connections (see CHART A-3).
^ EST CIRCUIT for short to ground.





EMISSIONS CHECK: ^ EGR SYSTEM: Valve operation.
NOTE: Refer to EMISSION CONTROLS for testing procedures.