Cranks Excessively Before Starting
- Fuel pressure gauge
- Wrench set
- Screwdriver set
- Protective eyewear and gloves
Before repairs begin, park the car on level ground, in park with the emergency brake set.
New Spark Plug Step 2 - For an engine to start up when cranked over the fuel system must be quickly pressurized. Not only does the fuel pump need sufficient pressure at start up, it needs to be able to hold pressure for a short amount of time while the engine is off. Perform a fuel pressure and regulator test using a fuel pressure gauge. Its also a good idea to remove the fuel filter to check for blockage.
Fuel Pressure Test Gauge Step 3 - An engine depends on vacuum to allow the engine to start up and run properly, if there are leaks in the vacuum lines the engine will have an extended crank time before starting. Inspect the engine's vacuum lines and repair broken or dilapidated lines.
Vacuum Line Step 4 - At the air intake port of the engine known as the throttle control motor or throttle bore, mass volumes of air leave deposits called coking. These impurities pass through the engine despite the air filter and build up over time. Servicing this unit as part of a regular tune up is necessary for proper operation.
Throttle Actuator Cut-Away Step 5 - The idle air control motor adjusts the amount of air via the computer released into the engine at idle. This device is subject to coking much like the throttle bore. To check this condition remove the IAC motor and inspect, if the plunger of the motor has deposits, clean with carburetor spray or replace the motor with a new unit. Also, clean the air passage ways with cleaner before re-installing the idle air control motor.
Idle Air Control Step 6 - The air intake boot connects air to the throttle body of the engine and if torn or broken it creates a lean fuel/air mixture causing excessive cranking. Inspect the air intake boot from the throttle body to the mass air flow meter.
Reinstalling Inspected Air Intake Boot Step 7 - A fuel pressure regulator regulates fuel pressure to the engine injection system. If a fuel pressure regulator diaphragm ruptures it can allow raw fuel into the engine through the vacuum feed line attached to the intake manifold. To check the fuel pressure regulator for this condition remove the vacuum line from the regulator and check for the presence of fuel inside the vacuum line, if fuel is present, replacement is needed.
Fuel Pressure Regulator Check Step 8 - Engine cylinder compression is needed for an engine to run properly. Once an engine has reached its life expectancy the compression drops due to piston ring and cylinder bore wear causing a longer than normal crank time. Perform a compression test to check for this condition.
Helpful Information The definition of extended engine crank time is, when the ignition key is turned to the crank position, the engine takes longer than usual before it will start running. (Extended crank time.) When an engine is cranked over it should fire up in about a three second time period. If a starter is weak it can cause the engine to crank slower than usual, which causes the engine to build compression slowly. This can be caused by a weak battery or starter motor with no malfunction of the engine. Best Practices
- Regular engine tunes up's and fuel filter replacement can stem hard starting conditions.
- To prevent engine cylinder low compression change motor oil and filter at recommended intervals.