GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Geo 🢒 1996 🢒 Metro 🢒 Engine 🢒 Engine Controls - 1.0L 🢒 Hard Start

Checks

Action

DEFINITION: The engine cranks OK, but does not start for a long time. The engine does eventually run, or the engine may start but immediately stalls.

Preliminary Checks
    • Refer to Symptoms .
    • Check that the driver is using the correct starting procedure.

Sensor Checks
    • Check the engine coolant temperature (ECT) sensor. Use a scan tool in order to compare the engine coolant temperature reading on a cold engine with the ambient air temperature reading of the same engine. A coolant temperature reading that is more than 5°C (41°F) different than the ambient air temperature reading (on a cold engine) may indicate a high resistance in the coolant sensor circuit or the sensor itself. Refer to Temperature Versus Resistance .
    • Check the throttle position (TP) sensor. A sticking throttle shaft or a binding throttle linkage will causes a high TP sensor voltage (open throttle indication). The PCM may not control the idle if a high TP voltage is present. Monitor the TP sensor voltage with the scan tool or a voltmeter. The indicated voltage should be less than 1.25 volts with throttle closed.

Fuel System Checks
    • Check the fuel pump relay for correct operation. The fuel pump should operate for 2 seconds when turning ON the ignition. Refer to Fuel Pump Electrical Circuit Diagnosis .
    • Check the fuel pressure. Refer to Fuel System Diagnosis .
    • Check for water contaminated fuel or inferior quality fuel. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
    • Check the operation of the fuel pump check valve. A faulty in-tank fuel pump check valve will allow the fuel in the fuel lines to drain back to the fuel tank after stopping the engine. This condition can cause hard starts, especially on hot soak restarts. In order to check for this condition perform the following steps:
        1. Turn OFF the ignition.
        2. Disconnect the fuel line at the fuel filter.
        3. Remove the fuel tank filler cap.
        4. Connect a radiator test pump to the fuel line and apply 102 kPa (15 psi) of pressure. The check valve is OK if the pressure holds for 60 seconds.

Ignition System Checks
    • Check for adequate secondary ignition voltage with a J 26792 spark tester or an equivalent.
    • Check the spark plugs for any of the following conditions:
       - Wet (fuel fouled) plugs.
       - A terminal screw that is bent or loose (rotate and pull).
       - A ceramic insulator that has cracks, carbon tracking or deposits (red or black dust)
       - A tip insulator that has cracks, carbon tracking, deposits (oil, carbon, glazing, fuel additive), or is loose (rattles).
       - A center electrode that is loose (wiggles side to side)
       - An incorrect spark plug gap that is too large or too small.
       - Platinum pads that are missing.
    • Check for bare or shorted ignition wires.
    • Check for moisture in the distributor cap.
    • Check for loose ignition coil connections.
    • Check for a worn distributor shaft.
    • Check all the ignition system electrical connections.

Additional Checks
    • Check the ISC system for proper operation.
    • Check for no crank signal.
    • Check the EGR valve operation. Refer to Exhaust Gas Recirculation (EGR) System Diagnosis .
    • Check for any Service Bulletin updates.