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Battery question and starting/idling issue

I have a 1998 Ford Taurus, and the battery in it is about 6 months old or so. I am a security guard and I spend anywhere from 6 to 12 hours in my car. I am always listening to NPR on the car radio at work. My question is, how long can I leave the key turned to the accessory notch and listen to the radio before I risk the battery going dead?

My starting/idling issue is strange. I will start the car and let it run for about 30 minutes to warm me up a bit, then turn it off. But, 30 minutes later when I go to turn it back on again it sputters and sometimes cuts itself off. I have to rev it way up to get it to idle and run.

Thanks for any help! This car is the key to keeping my job, so I need all the help I can get!

Many auto part stores will check your battery and charging system for free. Have that done.

I suspect you know what you are doing is hard on your car. Yea, I don’t expect you to change that, but it might be wise to make sure you change the oil more often than normally recommended.

The problems when starting I suspect may be related to something different. When was the last time the spark plugs and wires were replaced? How about the air cleaner? have there been any Check Engine Lights? All that engine idle time could have caused some sort of build up. Hopefully someone will know where that is likely to occur on your car.

The battery isn’t the problem for idling. You want to take care of those things which deteriorate on any car: spark plugs and wires, air and fuel filters; cleaning of the engine intake tract and the components in the intake. This is a really cheap thing to do even if it made no difference; but, there are reported favorable results. In the intake tract (the large black tube and throttle body) clean the MAF (Mass Air Flow) sensor with MAF Cleaner; use Throttle Body Cleaner on the throttle body and bore, and on the iac (idle air control) valve. RSVP

Because “your car is key to your job” how about purchasing a little back-up,a jump box,many uses,easy to maintain,safe to store. It used to be only the pro-tool trucks carried them,now they are every where.

Unfortunately what you’re doing to your battery is NOT good. Constantly draining it then recharging it not good. When you replace your battery I suggest you spend some extra money for a Deep Cycle battery (Optima makes a good one). It can handle the abuse you’re doing to your battery.

I agree that this type of use (repeated draining, more than 2-3%) will send your battery to a very early grave.

However a deep-cycle may not be the answer, since many deep-cycle batteries do not like the heavy amp draw to start a car. There is such thing as a “starting deep cycle” which is a compromise, and they only come in a few sizes so it might not fit.

I would get yourself a battery-powered boombox and some NiCad or Ni-Mh batteries…

Also, keep in mind that the REAL criteria for things like oil change interval and other engine maintenance are engine running hours - NOT just miles. So if you idle a lot, you should change your oil every 50 hours of running time.


Ok there’s a lot of questions here so I’ll try to answer all one by one.

Charging system and battery have been checked and are fine.
Of course I know what I’m doing is hard on my car but I either work or sleep under an overpass, no not much choice at the moment.
It gets oil changed every 3 months at the moment because it takes forever to drive it 3000 miles. I am not the only one that drives this car - my other half drives it during the day to work.
Plugs and wires and air filter were all replaced new a few months ago, and no check engine lights have come on at all.

We own a jump box.
We’ve used fuel system cleaner and gas cleaner to no affect.

My starting the car is not to listen to the radio…my starting the car is to warm myself up since I am having to sit out in temperatures reaching below the teens on some nights. I only have the key turned to “accessory” when listening to the radio.

My father brought up the point of the Check Valve…said it could be letting fuel drop back down to the gas tank when the car gets turned off after idling. He said to turn the key to the “on” position but not to start. Said listen for the fuel pump to come on, wait 10 seconds then start the car. This seems to have resolved the issue.

So the only question left now is how long can the accessory be left on before risking a dead battery?


However a deep-cycle may not be the answer, since many deep-cycle batteries do not like the heavy amp draw to start a car.

I’ll agree there are deep cycle batteries that don’t…but there are many that do. Optima makes a EXCELLENT Deep-Cycle battery that will have MORE then enough cold cranking power.

When the engine is turned off, residual fuel pressure should stay for several minuets. How long? It depends, but I’ve seen the fuel pressure stay up for several hours. The fuel pressure regulator, and leaking fuel injectors, will allow the fuel pressure to fall. This can result in a difficult start because the fuel pressure isn’t where it should be for a few seconds.
When you prime the fuel system by turn the ignition key to RUN, the fuel pump is energized for only TWO seconds when the engine isn’t running.
Check the fuel pressure with the engine running. Shut the engine off, and monitor the fuel pressure. If the fuel pressure falls off quickly, there is a problem with the fuel pressure regulator or/and the fuel injector(s) leaking.

You can probably listen to the radio for 12-16 hours before your battery won’t start the car, while the battery is in fairly new condition.

That time will decrease dramatically, the more discharge cycles you give the battery.

That is some very helpful information, and things I hadn’t thought of. Can you tell me precisely how to check the fuel pressure?

I should add that recently I added a bottle of Lucas to the fuel tank and it has been running better than usual…but still being somewhat troublesome.

It seems that if I try to start it any less than one hour after turning it off, it doesn’t want to stay running. It will turn over, sputter, the RPMs die and the engine cuts off. But if I wait an hour after initially turning it off, it starts and runs just fine.