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Discussion Starter #1
Settle in – clear your mind – I would appreciate (At this point even pay for!) ideas/feedback on this frustrating issue.

2015 Ecodiesel Bighorn 4wd big screen but no NAV 45K miles.
Started two weeks ago
Sometimes the truck starts – sometimes it doesn’t
When the truck doesn’t start – the starter engages but does not have enough power to turn over the engine and while this is happening the battery voltage (as measured at the Battery) drops to ~10V and stays there and then slowly climbs back to normal (~12.7V).
:mad:
Also during this time the interior lights are dim and when locked the Horn barely chirps vs the normal strong beep
Feels like a classic weak battery or bad battery connection issue until such time that it seems to heal itself and fires right up with a fast crank and no issues at all. I should mention that I’m testing a theory that this only happens when the truck is Hot from sitting outside in our heatwave of 90F + or when shut down from running in this heat.
Also while this was happening the only way to get the load off of the battery was to disconnect the battery terminal main lead. I tied all of the other fused link connections back to the battery while this was happening and they were not pulling the battery down- just the main lead tied to the main terminal connector.
Had the Battery load tested at autozone – their machine reported that it needed a charge but no other issues through a start/ headlight test.
Dealer’s best guess was that it’s a starter because other than what is apparently the normal voltage related codes logged there is nothing that would point them to anything else.

I hate to lay down $500 on a hunch and I struggle to understand how a starter issue could “heal” itself the way this thing is with the voltage coming back up all by itself. Even if it was the old school hit the starter with a hammer sort of thing or a starting sequence time out thing the voltage would immediately jump back up. This looks like a short that is healing itself consistently and then sometimes not a short at all.
 

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This is why I hate elec. I memory service me some others had problem with starter crapping the sheets in this manner
 

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2015 Outdoorsman EcoD CC w/6.4' 4X4
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I would suspect the battery first, it's cheaper to replace than the starter.
I've had those battery test machines be wrong before.
Only other thing to check would be voltage drop across the starter motor relay. You would have catch while it's acting up. Not sure where it's at, probably part of the starter itself.
 

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I would start with the battery. Battery issues on these electronic trucks cause weird problems.
 

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Discussion Starter #8
Quick update drove today - got it good and hot was planning to come home and when it wouldn't restart then hit it with the charger to see a little hit would matter. Also left the AC off the whole time (trying to change variables since this has been happening). No issue - restarted several times....
 

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Discussion Starter #9
Tomorrow I'll try again, no AC, and leave it bake in the sun all day. If I can get it to happen again - will immediately pull the leads to see if the battery recovers. Thinking if it immediately recovers it can't be the battery (took the load off)..
 

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Thing to remember about power. Volts are not an absolute power. Volts could be described as pressure but amps is the amount of flow. So if you are seeing 12 volts but only getting 30 amps the amount of work that is possible is very limited. If something in the battery has a poor connection then it could explain the intermittent starting. Easy way to test would be to put a jump start box on it when it doesn't want to turn over. My guess is your battery is on its way out. It is producing voltage you want to see but is not producing sufficient amps to power the starter.
 

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I had the exact same issue with the battery in my Tractor. Tested fine but all solved when I replaced it.

Sent from my LG-H812 using Tapatalk
 

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Read your OP first. Thought battery. Been through hell with the four batteries in my boat and all the batteries over decades in my more than a dozen motorcycles, tractors, vehicles etc. Often, as others so frequently discussed, battery tests do not transfer to the real world.

You think 90 is hot? 118 in the sun two days ago here. Mine starts. If it balks - battery first.

No way should you pay $500 for a new starter. There is that possibility of a bad spot on the armature. Happens. If I suspected that there are places that re-build starters for far less than that silly price quoted. On that issue, look around.
 

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Discussion Starter #13
Maybe it's FIXED!

Thing to remember about power. Volts are not an absolute power. Volts could be described as pressure but amps is the amount of flow. So if you are seeing 12 volts but only getting 30 amps the amount of work that is possible is very limited. If something in the battery has a poor connection then it could explain the intermittent starting. Easy way to test would be to put a jump start box on it when it doesn't want to turn over. My guess is your battery is on its way out. It is producing voltage you want to see but is not producing sufficient amps to power the starter.
Maybe the final update......
Slept on it last night and started thinking if there was truly this level of current draw on the battery for this amount of time (30 seconds for battery voltage to slowly recover from being drawn to 10V) then the battery would NEVR "recover" to anything close the to original voltage especially after several minutes of this. That being said - went out this morning and the truck was completely cool - IT WOULD NOT START!
Made a trip to Wally World and bought a battery.. Truck fired right up! two trips down - several starts with no issues! If I post again - it wasn't the battery!

Thanks all for the feedback - it made me think and convince my self it had to be the battery!
 

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Made a trip to Wally World and bought a battery.. Truck fired right up! two trips down - several starts with no issues! If I post again - it wasn't the battery!
WallyWorld carries AGM type batteries?
That is the factory type battery and my own opinion would not use a lead acid battery in any vehicle application if I don't have to.
 

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Discussion Starter #16
WallyWorld carries AGM type batteries?
That is the factory type battery and my own opinion would not use a lead acid battery in any vehicle application if I don't have to.
At this point 900CCA with a 3 year full replacement warranty for $127 will have to do....
 
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