CarTalk.com Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Vehicle will not start after one day of sitting

If vehicle sits for more than one day, it will not start. I had the charging system checked out and everything there is fine. What else could it be?

Identify your vehicle including engine size and mileage, last tune up or previous recent work done.

Plus, describe as best you can what does or does not occur when you turn the key to start.

If the battery has run down to the point where it will not start the engine, there is probably a constant current drain. This will take some circuit tracing to find the culprit. Start by measuring the battery idle current drain. Then start pulling fuses until you see the current drain drop. Then troubleshoot that circuit.

Hope that helps.

Something is draining the battery. There is a new battery in the vehicle.

How do you know that? How do you know it is not a problem with the starter or the wiring etc.

Tell us more.

"Identify your vehicle including engine size and mileage, last tune up or previous recent work done.

Plus, describe as best you can what does or does not occur when you turn the key to start."

Place an ammeter between the negative battery terminal and the ground cable clamp. Measure the current flowing. If it is higher than 25 milliamperes (0.025 amperes) the battery drain is confirmed. Now start pulling fuses until the drain drops. If none of the fuses causes the drain to disappear, disconnect the alternator B+ lead and see in the current drops. There are some ‘always hot’ loads that are protected by fuseable links so you may have to disconnect those. Also the starter solenoid is an ‘always hot’ unit so disconnect the hot lead to the starter if everything else fails.

Get back to us if you find something and need further help.