Engine won't start

[houtxPW]

This only lasted a couple days and then it happened again today. With the positive cable mounted on the terminal and the negative removed, with the truck completely off when I tap the negative terminal it creates a large enough spark that it tacks the cable end to the terminal. With both cables on the terminal my automatic charger will ramp up maximum amps, but when ibremove the negative cable from the battery terminal it drops to 1/3 of the amps it was pulling from the charger.... it was doing the same thing the other day, but when I took off both cable and held them together for a minutes and then waited a few minutes and put them back on, it didn't spark at all. No idea what's drawing the current so much it would spark like that with no charger and the truck completely off, but today when I tried the same thing it kept sparking and made no difference. I should mention while driving these days the dash say 14.2-14.4v, which is higher than usual...
So this morning the truck started right up, drove for 10 minutes, parked for 8 hrs and it would only click... charge connected to cables high amps, disconnect one cable lower amps, sparks, frustration, more charging, cold AF outside and finally I crawled under the truck with ignition set to run and poked blindly with a nut driver until hitting the right terminals on the standard to get it to turn, almost started, but couldn't find the terminals again. After a bit more fumbling I hit terminals that make it spin, but without the bendix engaging, so I let itbspin for 30 seconds, crawl out from under the truck and push the button and it starts, weakly, but started nonetheless.
I get home shut it off and cranks up easily, but the whole time @ 14.2-14.4 volts. I start it again pop the hood and remove the negative terminal, tap it and sparks fly. I push the cable down so it won't slouch and as I walk around the door the truck stalls, shouldn't stall bit it did. I slip the cable back on loose and start it then quickly remove the cable and run around the door... 13.4-13.5v. It has a little stutter every 15-20sec9nds but doesn't stall and I let it run for a minute. Then I slipped the cable back on the terminal and it was at 13.9v, took the cable off back to 13.5, slip it back on 13.9, Rev it and still 13.9. Tighten the cable on the terminal, 13.9, shut it off and start it back up(starter sounded quick than it has been) and it rises to 13.9v and stays steady.... I turn it off and on a couple times, every time 13.9v..sometimes it flutters to 13.8v, but mostly stays at 13.9v.... 1/14/24 - will update

So last night I bought a remote kill switch that auto-offs if voltage gets below 11.8v. I installed it this morning when i got to the office. After work truck started up, but starter did not seem super energetic. When I got home I did not turn the kill switch to off, because losing your cameras for a day sucks, but 3.5 hours after I got home I hit the oem fob for auto-start and nothing... hit "on" for the fob from Amazon and then hit the oem fob for auto-start and it started...
Not a waste of money for the kill switch, that is for sure... at least it gives me time to figure out what is the cause of the battery drain...


RVBOATPAT Remote Battery Disconnect Switch 12V 240A Kill Switch Automatic Power Shut Off Switch Remote Control Switch for Auto Car Truck Boat https://a.co/d/052EapD

 

[mbarber84]

Just adding to the discussion:

1. Remember that voltage alone is not necessarily an adequate measure of wether or not a battery is healthy. Amps are also part of the equation. A battery may read 12-13V when tested with a multimeter but may not have sufficient capacity in amps to turn the truck over. I’ve seen more than a few batteries in this condition. They will power up all of the trucks functions during the pre-start sequence but will fall flat on their face when attempting to actually spin the engine over. This is especially true in cold weather, where the additional drag from cold engine oil makes the engine harder to spin. Add to this the draw from the grid heater cycling (if it’s a diesel) and you have a recipe for a no-crank no-start situation.

2. There is a TSB out for 2022 trucks with intermittent or continuous long crank no-start, or no-crank no-start conditions. Apparently someone thought it was a good idea to use a non-conductive nut on the starter cable.

 

[Riddick]

So last night I bought a remote kill switch that auto-offs if voltage gets below 11.8v. I installed it this morning when i got to the office. After work truck started up, but starter did not seem super energetic. When I got home I did not turn the kill switch to off, because losing your cameras for a day sucks, but 3.5 hours after I got home I hit the oem fob for auto-start and nothing... hit "on" for the fob from Amazon and then hit the oem fob for auto-start and it started...
Not a waste of money for the kill switch, that is for sure... at least it gives me time to figure out what is the cause of the battery drain...


RVBOATPAT Remote Battery Disconnect Switch 12V 240A Kill Switch Automatic Power Shut Off Switch Remote Control Switch for Auto Car Truck Boat https://a.co/d/052EapD

Maybe I missed it but can you post some details on your truck such as year, mileage, engine, age of batteries installed?

9 times out of 10 when people are experiencing no start issues its the batteries. The Mopar batteries are junk and people generally get about 3 years out of them before they have to replace them.

Also, I am not a mechanic by any means but I would avoid disconnecting and reconnecting your battery with the truck running. I would think this is a quick way to possibly fry your alternator or other electrical components.

 

[Units]

I would avoid disconnecting and reconnecting your battery with the truck running.

Actually, this is the old “redneck” method to determine if it’s a bad alternator not charging the battery enough to start or if its just a bad battery, truck won’t continue to run once you disconnect the battery if the alternator is bad. If it continues to run then you know it’s the battery not holding a charge preventing you from starting your truck. Now, is there a more technical way to perform this test? Yes there is, but in a pinch you do what you got to do.

 

[Jimmy07]

Actually, this is the old “redneck” method to determine if it’s a bad alternator not charging the battery enough to start or if its just a bad battery, truck won’t continue to run once you disconnect the battery if the alternator is bad. If it continues to run then you know it’s the battery not holding a charge preventing you from starting your truck. Now, is there a more technical way to perform this test? Yes there is, but in a pinch you do what you got to do.

Even back 30-40 years ago before electronic control module, that might have been a neat novelty trick at best. But the whole premise of what people thought they were deducing by doing this is a fallacy, because the diodes in the alternator can be damaged because of the load dump by taking out the battery, leading to a potentially false diagnosis.
Doing that on vehicles nowadays, the voltage spikes can reach out to the electronic control modules, causing them to put out high reference voltages to sensors.

 

[houtxPW]

Maybe I missed it but can you post some details on your truck such as year, mileage, engine, age of batteries installed?

9 times out of 10 when people are experiencing no start issues its the batteries. The Mopar batteries are junk and people generally get about 3 years out of them before they have to replace them.

Also, I am not a mechanic by any means but I would avoid disconnecting and reconnecting your battery with the truck running. I would think this is a quick way to possibly fry your alternator or other electrical components.

2020 powerwagon, 6.4, uconnect 4c 12", equipped with every available option except trailer tire pressure monitor. no alterations made to vehicle except for the recently added kill switch, which is just from terminal to cable

 

[houtxPW]

2020 powerwagon, 6.4, uconnect 4c 12", equipped with every available option except trailer tire pressure monitor. no alterations made to vehicle except for the recently added kill switch, which is just from terminal to cable

i replaced the battery 3 months ago and got them to exchange it for a new one even though it tested good a week ago

 

[houtxPW]

Actually, this is the old “redneck” method to determine if it’s a bad alternator not charging the battery enough to start or if its just a bad battery, truck won’t continue to run once you disconnect the battery if the alternator is bad. If it continues to run then you know it’s the battery not holding a charge preventing you from starting your truck. Now, is there a more technical way to perform this test? Yes there is, but in a pinch you do what you got to do.

i am old and have been called a redneck before, so there's that..

 

[houtxPW]

Even back 30-40 years ago before electronic control module, that might have been a neat novelty trick at best. But the whole premise of what people thought they were deducing by doing this is a fallacy, because the diodes in the alternator can be damaged because of the load dump by taking out the battery, leading to a potentially false diagnosis.
Doing that on vehicles nowadays, the voltage spikes can reach out to the electronic control modules, causing them to put out high reference voltages to sensors.

well since it is already screwed up I figured what could it hurt and since it is still screwed up, I have deduced that it hurt nothing new. Meanwhile, it was better than replacing half a dozen parts that didnt need replacing