Jump Starting a M1008

[tgtaylor64]

My friends M1008 will not turnover when cranked. The starter is new and has the Doghead relay mod. The truck is stock 24 VDC. I tried using my M1009 and a NATO slave cable. His voltmeter on the dash showed almost in the green. Nothing. I verified 28 VDC+ on the buss bars. I can hear the Doghead relay click when I turn the key to start. I put in a known good front battery and the truck starts right up! Any ideas? Why did the jump start not work??

 

[doghead]

will not turnover when cranked

Please clarify this statement.

 

[amphi]

If the rear battery is near or fully charged and the front battery is low or dead, most of the voltage will be dropped at the rear battery resulting in less than 12v to the starting circuit (relay).

This is why it is important to follow the TM and wait three to five minuets before starting.

Quote from the TM:
"Wait 3 to 5 minutes after hooking up slave cable to "dead" truck, before attempting to start it. Damage to the truck’s electrical system may result if the truck is started sooner."

See this post: http://www.steelsoldiers.com/showth...cv-and-5-ton&p=1026048&viewfull=1#post1026048

 

[K9Vic]

Or this post.

http://www.steelsoldiers.com/showth...-ground-wire&p=1425950&viewfull=1#post1425950

 

[tgtaylor64]

Starter will not turnover, no sound except relay under dash.

 

[cpf240]

... I put in a known good front battery and the truck starts right up! Any ideas?...

I think you answered your own question. One, or both, of the batteries is bad. If the bad battery has a short, I don't think it will start, even with a jump.

 

[K9Vic]

I can confirm that if there is a bad battery it will not even jump. Had that issue with a M1009 and did not start with the slave cable and after putting in new batteries it stated just fine.

 

[tgtaylor64]

Buy why? Seems that the slave port is useless since the only time one would use it is to jump start due to dead batteries.

 

[HASSON1911]

Theres a difference between a bad battery(broken cells) and a dead battery(drained).

 

[K9Vic]

Theres a difference between a bad battery(broken cells) and a dead battery(drained).

Exactly, the batteries were 6 years old and were completely bad, not dead. I have jump started many CUCV trucks with drained/dead batteries.

 

[HASSON1911]

The other thing to add, if you do jump a truck with a bad battery(ies) and started it, you only started it because you used the juice from the jumper vehicle. Once you take off the cables, the truck is only taking juice from the alternator. Prolong use of this will burn it out, due to the fact the battery isn't holding a charge, and is using the power as quickly as its coming in. Just something to remember, and save you some pennies down the road!