Hard to Start

Definition: Engine cranks OK, but does not start for a long time. Does eventually run. If the engine starts but immediately dies (as soon as key is released from "start" position), "No Start or Stall After Start" CHART A-3.

^ Perform careful visual check as described at start of Symptoms. - Visual/Physical Underhood Inspection
^ Make sure driver is using correct starting procedure as provided in Owner's Manual. Ask the driver about conditions when the hard start occurs - hot or cold ambient temperatures, hot or cold engine, after hot soak or after an overnight stand.
^ Check ignition timing per emission control information label.
^ Perform "Dynamic Fuel Pressure Diagnosis" Chart A-4B. Fuel pressure should be maintained at 40-50 psi at key "ON" and engine "OFF". A-4B Dynamic Fuel Pressure Check
At key off, the fuel pressure shouldn't drop immediately but should stay at 40-50 psi and bleed off gradually. If fuel pressure falls off rapidly:
1. Visually check for fuel line leaks or injector leaks at key "ON,"engine "OFF".
2. Cap the fuel return line at the fuel rail. Key "ON" then "OFF" and note pressure drop. If pressure bleeds off rapidly, check for fuel pump not checking or for fuel leaks inside the fuel tank. Also check for injector sticking open.
3. If fuel pressure holds at key "ON" with fuel return capped, the cause is fuel pressure regulator leaking. To repair, replace fuel metering assembly.
4. Check for dirty (plugged) injectors and clean as necessary.
^ Perform "Injector System Diagnosis" Chart A-5. Chart A-5 Injector System Diagnosis
^ Check for water or other contaminants in fuel.
^ If the hard start occurs in warm ambients or after a hot soak, check for winter grade fuel or high alcohol content fuel. May be vapor lock.
^ Check HEI voltage output using ST- 125 HEI tester.
^ Check EST operation.
^ Check ignition system for:
a. Worn or loose distributor gear.
b. Worn or bent shaft.
c. Cap and rotor for moisture, cracks, dust, carbon tracking, etc.
d. Pick-up coil and ignition coil for proper type and connections.
^ Check spark plug wires by connecting an ohmmeter to ends of each wire in question. If the meter reads over 50,000 ohms, replace the wire.
^ Remove spark plugs. Check for proper type and heat range. Check for improper gap, wear, burned electrodes, sooting, fuel or oil fouling, heavy deposits, cracked insulators or signs of arcing.
^ Check for throttle linkage sticking or binding.
^ Check for TPS binding or sticking.
^ Check coolant sensor and MAT sensor accuracy. Observe coolant and MAT parameters (ED04 and ED05). Coolant parameter should be about equal to a thermometer reading taken in the radiator with the thermostat open. Compare the MAT parameter to a known good car in the same ambient temperature. MAT should approach coolant temperature at idle and decrease as the engine speed is increased. Look for unreasonable MAT and coolant sensor values and/or values that drop suddenly for no apparent reason. Check for high resistance in MAT and coolant connections and harnesses. Check MAT and coolant sensor terminals for being misformed and for corrosion. Repair harnesses or replace sensors as necessary.
^ Check for restrictions in the MAP sensor vacuum fitting or upper intake manifold MAP port. Check for vacuum trapped in the MAP sensor. Tee a vacuum gage into the vacuum hose at the fuel pressure regulator. The gage reading and parameter ED02 should be approximately the same and should respond quickly to changes in engine load. Clean out MAP port at the upper intake manifold or replace sensor as necessary.
^ Check for restricted exhaust or catalytic converter.
^ Check compression on all cylinders.
^ Remove rocker covers and observe valve operation. Check for bent push rods, worn rocker arms, broken valve springs, worn cam lobes.