Hard to Start

HARD START
Definition: Engine cranks OK, but does not start for a long time. Does eventually run, or may start but immediately dies.

IMPORTANT PRELIMINARY CHECKS
Before using this section you should have performed the "On-Board Diagnostic System Check" - Powertrain/On-Board Diagnostic System Check and determined that:
1. The control module and MIL (Service Engine Soon) are operating correctly.
2. There are no diagnostic trouble codes stored, or there is a diagnostic code but no MIL (Service Engine Soon).
^ Several of the following symptom procedures call for a careful visual/physical check. The importance of visual/physical checks cannot be over stressed. because they can lead to correcting a problem without further checks and can save valuable time.

VISUAL / PHYSICAL CHECK
This check should include:
^ Control module grounds for being clean, tight, and in their proper location.
^ Vacuum hoses for splits, kinks and proper connections, as shown on "Vehicle Emission Control Information" label Check thoroughly for any type of leak or restriction.
^ Air leaks at all mounting areas of the intake manifold sealing surfaces.
^ Ignition wires for cracking, hardness, proper routing, or carbon tracking.
^ Wiring for proper connections, pinches, and cuts.
^ The following symptom charts contain groups of possible causes for each symptom and cover several engines. These procedures are not necessarily meant to be done in consecutive order. If Tech 1 scan tool readings do not indicate the problems, then proceed in a logical order, easiest to check or most likely cause first. To determine if a particular system or component is used on a specific vehicle, refer to the "Electronic/Powertrain Control Module (ECM/PCM)" Wiring Diagrams for application. Electronic/Powertrain Control Module (ECM/PCM)

^ Make sure the driver is using the correct starting procedure.

SENSORS
^ CHECK: Engine Coolant Temperature (ECT) sensor Using a scan tool, compare engine coolant temperature with ambient temperature on a cold engine.
- If coolant temperature reading is 5 degrees greater than or less than ambient air temperature on a cold engine, check for high resistance in coolant sensor circuit or sensor itself. Refer to "DTC 15" and compare resistance values. DTC 15

^ CHECK: Throttle Position (TP) sensor If a sticking throttle shaft or binding linkage causes a high TP sensor voltage (open throttle indication), the control module will not control idle. Monitoring TP sensor voltage. Scan tool and/or voltmeter should display less than 0.85 volt with throttle closed.

FUEL SYSTEM
^ CHECK: Fuel pump relay operation. Fuel pump should operate for 20 seconds on vehicles with a fuel module and for 2 seconds on all other vehicles when ignition is turned "ON." Refer to "CHART A-5". Chart A-5 Fuel Pump and Relay Electrical Test
^ CHECK: Fuel pressure. Refer to "CHART A-6". Related Tests, Information and Procedures
^ CHECK: For water contaminated fuel.
^ CHECK: Fuel pump relay Connect test light between fuel pump "test" terminal and ground. Test light should be "ON" for 2 seconds following ignition "ON." If not, refer to "CHART A-5". Chart A-5 Fuel Pump and Relay Electrical Test

IGNITION SYSTEM
^ CHECK: Ignition system for:
- 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.
- Moisture in distributor cap
- Worn distributor shaft.
- Pickup coil resistance and connections
- Loose ignition coil connections.

^ CHECK: CKT 423 (ignition control) for short to ground.

ADDITIONAL CHECKS
^ CHECK: IAC operation - refer to "DTC 35". DTC 35
^ CHECK: EGR operation. Testing and Inspection
^ CHECK: Service Bulletins for PROM updates.