sandcobra164
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- Leesburg, GA
I've got some questions to an electrical guru. My M1028 will not start as the engine turns over very slowly.
Known.
1. Both batteries are good to the best of my knowledge. Both show an open circuit voltage while connected to the truck of 12.7 volts. I hooked my "smart" charger to them and they both showed 95% upon hooking up and I let them go through a charge cycle seperately. Water level is fine in all cells and no sulfation or corrosion noticed on plates in the cells or terminals. Regular 6TL batteries within past few years.
2. Truck will slave start just fine when connected to the Deuce through the NATO Slave receptacle on both vehicles.
3. Truck will not jump start using a running vehicle connected to either battery. Curiously, if I have the jumping truck hooked to the rear battery, it will shut off once I attempt to start the CUCV. Does not happen when hooked to the front battery. Yes, I do know to hook positive to positive and negative to negative of only one battery at a time.
4. Both Gen lights come on and glowplugs go through their cycle normally whether hooked to a vehicle or using it's own battery power.
5. Truck no longer has the resistor pack for the glowplugs behind the air filter. The glow plug relay pulls 12 volt power from the firewall as per the instructions posted to eliminate the resistor and has been wired that way for about 2 years. It does still have the 24 volt starter and the original starter relay. I looked at the wiring under the dash and see no evidence of heat or melting wires. The relay still sounds off as normal.
At this point, I'm assuming a bad ground. I've thought of testing this by hooking a heavy jumper wire from the negative terminal of the front battery to the engine block to test. I'm hesitant to do so as I don't want to upset the 12 volt 24 volt setup on this truck. The starter is the only thing left on the truck that is 24 volt and it's ground to the block by being bolted to it so running a jumper to test shouldn't hurt anything. I'm asking for advice as this is my pristine all original M1028 with only 6,900 miles on it. I can't take any chances on my youngest son Briggs favorite truck. Same one that won MV of the Month last month. Up one day, down the next!!!
Known.
1. Both batteries are good to the best of my knowledge. Both show an open circuit voltage while connected to the truck of 12.7 volts. I hooked my "smart" charger to them and they both showed 95% upon hooking up and I let them go through a charge cycle seperately. Water level is fine in all cells and no sulfation or corrosion noticed on plates in the cells or terminals. Regular 6TL batteries within past few years.
2. Truck will slave start just fine when connected to the Deuce through the NATO Slave receptacle on both vehicles.
3. Truck will not jump start using a running vehicle connected to either battery. Curiously, if I have the jumping truck hooked to the rear battery, it will shut off once I attempt to start the CUCV. Does not happen when hooked to the front battery. Yes, I do know to hook positive to positive and negative to negative of only one battery at a time.
4. Both Gen lights come on and glowplugs go through their cycle normally whether hooked to a vehicle or using it's own battery power.
5. Truck no longer has the resistor pack for the glowplugs behind the air filter. The glow plug relay pulls 12 volt power from the firewall as per the instructions posted to eliminate the resistor and has been wired that way for about 2 years. It does still have the 24 volt starter and the original starter relay. I looked at the wiring under the dash and see no evidence of heat or melting wires. The relay still sounds off as normal.
At this point, I'm assuming a bad ground. I've thought of testing this by hooking a heavy jumper wire from the negative terminal of the front battery to the engine block to test. I'm hesitant to do so as I don't want to upset the 12 volt 24 volt setup on this truck. The starter is the only thing left on the truck that is 24 volt and it's ground to the block by being bolted to it so running a jumper to test shouldn't hurt anything. I'm asking for advice as this is my pristine all original M1028 with only 6,900 miles on it. I can't take any chances on my youngest son Briggs favorite truck. Same one that won MV of the Month last month. Up one day, down the next!!!
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