Hard to start or extended cranking
When an engine cranks for a long time before it starts, either spark or fuel is missing or weak and each has its own reasons. Most of the time, the air / fuel mixture has been disturbed and there is too much air or not enough fuel. Many sensors report to the computer, who then takes that input and controls fuel or air delivery, is suspect when diagnosing long cranking times. A bad coolant sensor, a bad throttle position sensor (TPS), a bad fuel pump or a plugged fuel filter can all cause a lean condition causing long cranking times. Sometimes the spark is delivered late, weak or not at all. A weak coil or bad coil wire, a bad pick up coil or crank sensor or a bad rotor can all cause a change in the spark.
If you know when it will not immediately start, try spraying carb cleaner or starting fluid in the duct that carries air to the air filter. If by adding "fuel" the engine always starts faster and cranks over less, then you will know its a fuel delivery problem and can pass on to your tech, the process you used and the results.
Another easy thing that you can do is simply change the spark plugs. As always, if the problem changes, for the better or the worse, you are on the right track. If you do not see a decrease in the cranking time then most likely it is a fuel delivery problem.
You might also use a fuel additive each of the next 2-4 times you fill up. Look for something that claims to remove intake valve deposits. These deposits act like a sponge and soak up the fuel as it is sprayed on the back of the intake valve. So if the engine is warm or cold, this sponge has to be saturated and begin to drip before the engine will start and extended cranking is one of the classic symptoms. By trying the fuel additive and thinking of this as a diagnostic procedure, if your problem gets better, continue to use the fuel additive. No change, stop using the additive. Additives I like are "Techron Fuel Injection Cleaner", "Techron Concentrate plus Complete Fuel System Cleaner", "Pyroil Total Fuel Injection Cleaner" and "Valvoline Total Fuel Injector Cleaner" . We use and sell it in packages of three cans and our customers that we suspect have excessive intake valve deposits tell us their car is much better after they have used three cans or three tankfulls of additive.
If it is a "warm restart extended cranking", almost always it is low fuel pressure caused by a plugged fuel filter or a bad fuel pump.
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