Q: Fuel pump engages. Batery good, alternator good volts, jump start helps when wont start. Temp does not matter. Intermittent?

asked by on December 11, 2016

Truck wont start after trying several min.started. 8 hours later try to start with no luck. tried and the situation got worse seemed as if I had a bad battery. after 15 min jump charge. good start. bought Budget Battery. replaced. Good start. next morning no start. several min later jump-started off of a vehicle without charge. 8 hr later tried start. Good start. to upgrade battery. check volts on Budget Battery. check good. tried starting truck. no start. jumpbox start no luck. better cold crank amp batery. no start. jump-charged 10 min. Good start.check alt volts. 14. good. Test ORIGONAL core. good battery. Used core. charged. Good start. next morning good start. 5 hours later had to jump start. Next morn, good start. Every time good start now. Fuel pump hums. batery good. New batery good. Alt good. Diods good. Relay good. Why jump start?

My car has 133000 miles.
My car has an automatic transmission.

Hello. Thank you for writing in. There are several reasons your vehicle may only start when jump starting. The first and most common is a build up of resistance that is causing you to need a boost of voltage to get the engine started. This may be due to poor battery cables, a bad ground connection, a poor starter solenoid, and a couple of other issues. The first thing you want to do is perform a visual inspection of the starting system. Make sure there is no corrosion build up in the battery cables. You can also check the resistance across these wires and make sure you have a solid connection between components. You then want to make sure the starter solenoid is doing its job. It is responsible for taking the small amount of electricity sent by the ignition and turning it into a huge electrical charge that is strong enough to push over the engine with the help of some gear ratios in its favor. Do some more testing, and stick to the basics before assuming its something seriously complicated.

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