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Hello all. I have an 88 Town Car and i have a tricky problem. The battery is only a yr old and is holding plenty of voltage to turn the engine(12.4 volts). When i turn the key its sucks a boat load of power from the battery and it will respond like the battery is dead. within ten minutes or so the voltage returns to well above 12 volts. I tried switching out the starter solenoid with an extra and i got the same response. The starter cable does not seem to be corroded. it does start with a jump but with extreme difficulty. any ideas???
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Turn on your headlights. If they go completely out while starting the car you have an open circuit in a cable or the battery. If they get dim but stay on, you may have a heavy load on the battery. Perhaps a dragging starter.
What is the voltage while you are trying to start the car? Also measure the battery voltage while the car is running. It should be at least 13v.
[quote=”twiggy02919″ post=34006]What is the voltage while you are trying to start the car? Also measure the battery voltage while the car is running. It should be at least 13v.[/quote]
Sorry, i was in a hurry when i posted this. The voltage is about 14.1 with the car running but my leads are too short to see it while im turning the key because the hood goes on for days. im gonna try a couple more things and ill get back
[quote=”jdub1022″ post=34048][quote=”twiggy02919″ post=34006]What is the voltage while you are trying to start the car? Also measure the battery voltage while the car is running. It should be at least 13v.[/quote]
Sorry, i was in a hurry when i posted this. The voltage is about 14.1 with the car running but my leads are too short to see it while im turning the key because the hood goes on for days. im gonna try a couple more things and ill get back[/quote]
So it seems the alternator is doing its job to keep the battery charged up. And you said you’ve changed your battery so for now we can assume it’s ok (just for now).
A “dead” battery will often show full voltage while no current is being drawn. Next time you can’t start your car, turn your headlights on, and then measure the battery voltage. I just did on my car and its drops to 12V on a good battery.
I think there is a chance that you have a parasitic draw draining your battery preventing you from having enough juice to start your car.
To check for parasitic draw, disconnect the negative battery cable and put an ammeter between the neg battery post and your neg cable. You should have less than around 60mA (i forget the actual number Eric has a video on this too).
[quote=”twiggy02919″ post=34052][quote=”jdub1022″ post=34048][quote=”twiggy02919″ post=34006]What is the voltage while you are trying to start the car? Also measure the battery voltage while the car is running. It should be at least 13v.[/quote]
Sorry, i was in a hurry when i posted this. The voltage is about 14.1 with the car running but my leads are too short to see it while im turning the key because the hood goes on for days. im gonna try a couple more things and ill get back[/quote]
So it seems the alternator is doing its job to keep the battery charged up. And you said you’ve changed your battery so for now we can assume it’s ok (just for now).
A “dead” battery will often show full voltage while no current is being drawn. Next time you can’t start your car, turn your headlights on, and then measure the battery voltage. I just did on my car and its drops to 12V on a good battery.
I think there is a chance that you have a parasitic draw draining your battery preventing you from having enough juice to start your car.
To check for parasitic draw, disconnect the negative battery cable and put an ammeter between the neg battery post and your neg cable. You should have less than around 60mA (i forget the actual number Eric has a video on this too).[/quote]
I had previously determined the alternator to be fine. Like i said the car will start with a jump but with extreme difficulty. like i also said previously, the battery is almost new (only a yr old) so ill be extremely angry if thats it. i dont own an ammeter. will a multimeter measure that low of a number?
You can use a multimeter. Sorry I wan’t specific but I said “ammeter” meaning a multimeter in ammeter mode. Just make sure you set it to DC amps not AC.
You might want to follow the steps in the video that’s been posted on checking the starter because for starters a good static charge for a batter should actually be 12.6V. That said you need to start your testing at the batter with a load test or a conductance test before you go any farther. The auto parts store may be able to help you with this as they often do this test for free. In addition it’s very important that you have a good clean, tight connection at the battery, if not all kinds of problems can result, here’s a video that illustrates that problem.
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