Electrical Starting Problems on 77 CJ7

[Gibber]

I just bought a 77 CJ7 for my wife as a surprise bday gift. 304, PS/PB/Auto with Vintage AC. Battery was about gone when it was delivered from Broken Arrow OK to us in Oneida TN. Bought a new battery and it started right up. Ran it for a few min and then shut it off. Next morning I tried to start it and the voltmeter went right to zero and would not turn over. Battery checks OK and all the lights, etc work with the key to ON. After several tries it turned over and started. So it is intermittent. I'm thinking bad starter as to me that would send the volts to zero as the starter relay energized. The starter relay looks original too. Open to any ideas!

Thanks,

Mark

 

[gert]

i would say if its going to 0 volts its pulling a lot amps and usually that would be the starter. if you wanna know for sure you can wait til it does it again and smack the starter a few times with a hammer to un stick it.

 

[gert]

Also a good idea to check your grounds and battery terminals, I run a big ground wire straight to the starter mounting bolt, frame, and body

 

[ShepsCJ7]

Make sure it's in neutral, parking brake on. Then try jumping the starter out by old screwdriver between the solenoid post. If it starts every time replace the solenoid. If not then replace the starter. This is after making sure all cables are tight and have good grounds.

 

[Armyvet25]

betting on battery cable, complete loss of power is usually either in the ignition switch or a bad battery ground connection or pos connection.

 

[ShepsCJ7]

betting on battery cable, complete loss of power is usually either in the ignition switch or a bad battery ground connection or pos connection.

I had a solenoid crack on me when I was tightening the cable on giving that extra little snug. Didn't know it and chased the problem for a bit until I was removing it to bench check it and noticed it was cracked causing it not to make internal contact. First thing I did was check all my cables and make sure they are gudentite. Then when the problem continued it was my next step.

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[TSB8C]

A poor POS or NEG connection from the battery will definitely make the volts drop when trying to start. Check battery post ends of both cables, then POS cable on solenoid, then POS cable from solenoid to starter. Then check NEG cable from battery to engine ground (not a frame or body ground, although should also be there with a secondary wire from the battery NEG post side).

While a bad solenoid can certainly cause a starting issue, it would not normally cause the volts to drop to zero when trying to start. You would get clicking, clattering, or slow/no turns of the starter.

Next would be the starter itself. It could also cause volts to drop to zero if it's bad as well. Internal binding (rust, corrosion, etc) or an internal wiring issue (shorted winding) would cause the voltage drop. If binding, the hammer smack idea is a good diagnosis.

 

[Armyvet25]

....gudentite.....

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Bless you....

 

[NotTJ]

I had a similar issue with my 258. It was the starter solenoid on the inner fender. I replaced cables and solenoid at the same time just to have it all tight. Went with 2 gauge instead of 4 just so I know its getting full juice.