It's been about a month now since I got my mustang up and running again since I rebuild the motor. But, it's been giving me issues with the battery, at first something was draining my battery, now it struggles to start. I always have to jump it from another car or get one of those mini starters to jump the battery to get it going. I even check the voltage on the new battery and it always reads 12.3V. What else could it be?

Oh by the way like i said it even struggles to start when i jump it. ( if that helps)

Anyone else have this problem or have any ideas what I can look at?

Thanks!

 

What's the condition of your groundS?

 

Is the alternator putting out 14+ volts?

You could have baked the battery by cycling it too much.

Voltage at rest (12.3) doesn't mean anything, have someone hold the voltmeter across the battery while you crank it. If it drops down significantly (9-10v) and the battery is charged, it's given up the ghost.

What was draining it?

 

I had this problem on one of my other cars and it turned out to be a bad battery cable. It's a cheap fix, might be worth a shot.

 

I'll take a look at it this weekend but, thanks for the tip about the cables, because I've already had the alternater test, the starter, and changed out the batter and ignition cylinoid

 

Don't know if you've checked this, so I'll mention it.

Make sure that all your cables are in good condition and that their connection is solid. Your battery to solenoid and solenoid to starter. You might also want to try a new solenoid (third time is a charm ;-).

Then also make sure that the ground wire is connected properly to the chassis AND that you have a really good connection from your chassis to the engine block.

Ground issues are such a pain in these old classics, so spend a little money making sure your main battery connections are 100%.

Btw. do any of your cables get hot during cranking? If they do, it's a dead givaway of a high impedance wire/connector.

Hope you get it fixed.

 

+1 on baking the batt. I had a somewhat older battery (tho at the same time the car was rarely turned on) and it seemed that unless i was driving ALL the time it was draining itself. after checking wires and the alt, i just replaced the battery and all has been well since

 

Not fully charged, whats the voltage with the car running? Should be around or over 14V when its needing a charge & with a good charging system could reach 15 volts easily in A LOW CHARGED STATE.
http://www.batterystuff.com/tutorial_battery.html

Rick

 

Thanks for the tip guys, I'll definately look into it this weekend

 

Struggling to start with another 12 v source could indicate the engine is not timed properly.