Posted By |
Discussion Topic:
Voltage required at starter
|
|
f1tom |
12-09-2010 @ 11:17 PM
|
|
|
Member
Posts: 5
Joined: Mar 2010
|
Been driving my '36 Ford at least once a week with easy start ups. Today on the first try it didn't catch and there after "nothing''. Have lights and horn. Checked voltage at battery posts (Optima), shows 5.94V, at the foot starter switch and starter terminals: 3.74 V, when depressed. What should the voltage be at these locations and what should I look for that could be the problem? Thanks, Tom
|
Pauls39 |
12-10-2010 @ 1:38 AM
|
|
|
Member
Posts: 81
Joined: Oct 2009
|
You should be seeing 6.6 volts or better at the battery. The number one suspect would be you battery cable ends and posts. Check all the connections including the grounds, everything should be clean and shiney. Clean the cables, then charge your battery. Test the charging system after you get it running, you should then have around 7v at the battery with the engine running.
|
4dFordSC |
12-10-2010 @ 5:02 AM
|
|
|
Member
Posts: 266
Joined: Oct 2009
|
Also, make sure you have the proper-sized battery and starter cables for 6v, not the smaller cables for 12v.
|
drkbp |
12-10-2010 @ 5:34 AM
|
|
|
New Member
Posts: 180
Joined: Aug 2010
|
My '35 was doing that. Be sure your starter switch is good. Mine was shorting. There is not much insulation leeway on the back of that starter switch. New proper size cables and switch two months ago, spins the starter like a 12 volt. It could be just what the guys are saying though and I would try that first. Ken in Texas
|
TomO |
12-10-2010 @ 9:05 AM
|
|
|
Senior
Posts: 7250
Joined: Oct 2009
|
Try slow charging your battery for at least 24 hours and see if you can get a voltage reading above 6.5 volts with nothing turned on. If not, you will have to bite the bullet and buy a new battery.
Tom
|
supereal |
12-10-2010 @ 10:19 AM
|
|
|
Senior
Posts: 6819
Joined: Oct 2009
|
Place the probes of a voltmeter on each side of every connection as you engage the starter button. Any reading indicates the amount of voltage lost in that section of the circuit. Start at the battery and work toward the starter. At 6, or even 12, volts, it doesn't take much to lose most or all of the power. Be sure your starter motor is well grounded. We run a cable from the ground strap to one of the starter mounting bolts to be sure. A 12 volt cable with eyelets on each end will work. Your starter motor may be the problem, of course, or an old battery with a high resistance cell. More often than not, it is the starter switch that is bad. After being sure the car is out of gear, using a jumper cable connect from the "hot" side of the battery directly to the starter. That will usually tell you which end of the circuit is causing the problem. When diagnosing an electrical problem, always do these tests before you begin to disturb the connections, or you will often mask the initial cause.
|