Q: Battery the car runs fine when jumped if I shut it off and try to turn it back on it will not start unless jumped

asked by on

The car won't start unless you jump it it runs fine when running but as soon as I turn it off it won't start I change the battery and alternator the wires are good I have checked out all is the some kind of sensor that would keep my car from charging it also started to drop into neutral wilt driving I shift down and back up and it works fine for about twenty miles then I have to shift manually again

My car has 198354 miles.
My car has an automatic transmission.

During the most recent episode when the car yet again failed to start, the diagnostic would begin with testing of the battery. If you have a fully functioning charging system (you mention the alternator is new but charging system should still be tested) and the battery is new, and was fully charged when you last left the car, but the battery turns out to be now be "discharged", in that scenario you have a parasitic (excess) load on the car’s electrical circuits that is causing the battery to discharge even when the car is off. If there is excess current flow that is slowly draining the battery, a Mechanic would use an ammeter to test all of the various circuits until the faulty circuit with the excess load (current draw) is found. Then that circuit is traced to find the fault and repair it. That requires an electrical diagnostic.


A second possibility would be considered if the battery tests fine (fully charged, not discharged as in above scenario) and yet there is no starter motor operation. In that scenario, that is if there is no starter operation with the key held in the "start" position, the procedure is to test for power to the starter motor. If there is no power, then the electrical circuit supplying the motor has a fault. That circuit begins at the battery and includes grounds, wiring (some of which is very heavy cabling), fuses, relays, the ignition switch and terminations. Basically, with a fully charged battery, and with the key held in the "start" position, the starter is either getting power or it isn’t. With the key in the "start" position, if the starter motor is getting power but the starter doesn’t work, then the starter is condemned and replaced. On the other hand, with the key in the "start" position, if there is no power to the starter, then the circuit is traced until the fault in the circuit is found. In addition to a faulty ignition switch, faults can include high resistances, due to corrosion, wire strand breaks, or loose terminals, which can only be diagnosed using a voltage drop test. If you desire that a certified mechanic resolve this, please simply request a no start diagnostic and the responding certified mechanic will get the problem diagnosed and repaired for you. Requesting any of the above services I have referred you to will get you to the same end point: we will get the fault diagnosed and repaired. Please let us know if you have further concerns or questions as we are always here to help you.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Battery the car runs fine when jumped if I shut it off and try to turn it back on it will not start unless jumped

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Q: Car will not start

Hello, thanks for writing in. If the crankshaft position is off then that can keep it from starting. Prior to doing anything else I would do a compression test. If there is low compression then the valve timing is off....

Q: A Sensor is Faulty

Hello. If the speedometer is not working and you are getting this code, then the vehicle speed sensor needs to be replaced. This will cause all of this to occur. This sensor is located on the transmission. In some cases,...

Q: Q: Car not shifting into gear

Hi there. This sounds like an issue with either your shifter linkage or the shift solenoids inside of your transmission. These solenoids tell your transmission what gear to shift into. In addition, it is possible that your transmission does not...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...