Engine Won't Turn Over

grsthegreat · Dec 29, 2011

A bad battery can force current to ground. not sure why this happens, but i have seen it happen in 2 separate instances. Once on an older ford bronco. Everyone was sure that the ground wires or the positive wires were bad. when we tried to jump it sometimes we'd even see some smoke.

All the dash lights would fade out .. no start.

Finally took the old battery out and popped in one from another rig, and the truck started right up.

The second one was on my old JD870 tractor. I was sure it was the fuse or the cables again. Messed about for a day, charging battery, etc. Nothing.

Jumping also didnt help. I have a feeling a bad battery just robs all the jumping batteries amperage.. but i have no proof of this happening. All i know is i put in a new battery, and it fired up just fine.

papa51 · Dec 29, 2011

Had battery checked at local service center and it's fine. I've got it on a slow overnight charge since it's already out. I'm going to start at the battery and work forward tomorrow. I'm now thinking it might be the ground cable. It sure seems to be small gauge wire for a ground connection and does show some signs of excess heat at the clamp. I'm going to go down a gauge or two and replace the clamp, just to be safe. I'll post my findings.

Thanks

Dbellrn · Dec 29, 2011

Papa, once you get all the cables hooked back up to the battery, take a volt meter and put the positive test lead on the negative post of the battery then put the negative test lead on an exposed portion of metal on the engine block. This is called a voltage drop test. Ideally it should read next to nothing. If you have a bad ground it will show up to and including battery voltage. The current is flowing through the meter instead of the cable.

papa51 · Dec 29, 2011

Great tip, Dbellrn. I'll put this in my catalog of "things to try" for future use!!!

papa51 · Dec 30, 2011

Problem solved. Dbellrn was dead-on with the ground issue. At some point, a limb or broken sapling had wedged it's way between the ground wire and frame connection. I noticed this the first day and removed it. However, what I didn't know, and what could have been detected with a tug or two, the limb had pulled the ground cable enough to loosen it in the frame connector. While it hadn't been pulled completely free, it had been pulled enough to compromise the connection.

Thanks to everyone who offered advice, but especially to Dbellrn.

NOTE: I tried voltage drop test after I had corrected the problem and got a very minimal readout, next to nothing. You can bet I'll remember this tip!! Thanks

grsthegreat · Dec 30, 2011

papa51 said:
Problem solved. Dbellrn was dead-on with the ground issue. At some point, a limb or broken sapling had wedged it's way between the ground wire and frame connection. I noticed this the first day and removed it. However, what I didn't know, and what could have been detected with a tug or two, the limb had pulled the ground cable enough to loosen it in the frame connector. While it hadn't been pulled completely free, it had been pulled enough to compromise the connection.

Thanks to everyone who offered advice, but especially to Dbellrn.

NOTE: I tried voltage drop test after I had corrected the problem and got a very minimal readout, next to nothing. You can bet I'll remember this tip!! Thanks

glad you got it fixed...but im confused, in your 2nd post you said all ground wires were removed and re-tightened.??

oh well, glad all is now working good:thumbsup:

papa51 · Dec 30, 2011

Allow me to clarify, grsthegreat, initially I removed the clamps from the battery terminal, cleaned and re-tightened. Then I removed the ground from the frame and cleaned the frame of paint. I SHOULD have checked the wire to connector fit and I would have found it was not tight. Apparently the offending limb had put just enough force on the cable to loosen it inside the connector to the point the connection wasn't sufficient to complete the ground but not loose enough to be noticeable to the eye.

Thanks for your help and sorry for the confusion.

grsthegreat · Dec 30, 2011

papa51 said:
Allow me to clarify, grsthegreat, initially I removed the clamps from the battery terminal, cleaned and re-tightened. Then I removed the ground from the frame and cleaned the frame of paint. I SHOULD have checked the wire to connector fit and I would have found it was not tight. Apparently the offending limb had put just enough force on the cable to loosen it inside the connector to the point the connection wasn't sufficient to complete the ground but not loose enough to be noticeable to the eye.

Thanks for your help and sorry for the confusion.

ohhh, ok i see what you mean now.

again, glad all is well in the world again for your tractor