Q: Stalling then hard to start

asked by on December 09, 2016

Pretty much most mornings, vehicle starts straight away, but then won't idle and cuts out. Will start when hold pedal to floor and then have to let it idle until you feel it stabilise. There will no problem starting to for the rest of the day, only ever happens in morning or I guess when sat still for mor than 10 hours or so. Vehicle has had thorough service ie all filters, fuel cleaners, throttle body service, valve kit r , glow plug replacement, all been done.

My car has 70000 miles.
My car has an automatic transmission.

When you start your car in the morning and turn the key to on, the coolant temperature sensor immediately reads the temperature of the coolant and relays this to the computer indicating that the coolant is cold. The computer then knows at this point that it needs to enrich (add more fuel) the air/fuel mixture at startup due to the change in air density. When you start the car, you will notice that it idles high for a period of time until the engine warms up. This is the enrichment cold start process. This is done with what is called a cold start injector which injects more fuel into the motor until the engine reaches a specific operating temperature. The computer simply feeds a little extra gas through the fuel injectors to start the engine and then maintains a certain amount of fuel supply to the motor until it is warm. I would recommend having an expert from YourMechanic come to your location to take a look at your vehicle and diagnose your cold start issue.

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