Scan Gauge showed 20 volts! (1 Viewer)

[DanMedeiros]

Good afternoon Mud' community,

I had a very weird day with the cruiser. I was driving home and all of the sudden my voltage warning light came on and my scan gauge starting reading a charging voltage of 19.5 volts! I pulled off ASAP and turned the truck off. Truck would not restart. When I turned the key to "ON" the check engine light did not come on. I have been told this means the EFI relay blew. I changed it and the truck did not start.

So I had to get it on a flatbed and sent home

There is some history with this issue. Two weeks ago I took my truck in to my favorite cruiser mechanic that I have known for years. I asked him to change out my fusible link too since I was about to go on a big trip. Every since my charging voltage has fluctuated quite a bit on the scan gauge. It blew the EFI fuse and I had to replace it. Then the truck fired back up. I took it back to the shop and they replaced the alternator which was super expensive.

I was hoping that would fix the problem. The last few days every so often have been getting intermittent voltage alarm (red light) on startup. If I turned the car off and restarted, it would go away.

Anyone have any clue WTF is going on? My mechanic is an awesome guy but I think he is missing something. FYI I have dual batteries. I tried restarting with the batteries disconnected. My batteries are odyssey AGM

 

[Tools R Us]

Sounds like a bad connection or an intermittent short. Is the harness tied away from the EGR pipe?

 

[DanMedeiros]

Sounds like a bad connection or an intermittent short. Is the harness tied away from the EGR pipe?

I'll ask them to check

 

[LINUS]

Someone had a brand new fusible link that was bad out of the package, if this all started with that event - I'd be either swapping back my old one or buying another.

- Not like they're big $$$ & a spare (if your present one checks out) in the quarterpanel storage area is smart like an EFI relay.

Everything is getting older on these rigs - and while our motors may go 1/2MM miles, the other components may need a few swaps to that lifespan.

 

[Mrtwooooo]

I seemed to have a similar issue awhile back. I didn't have any trouble with restarting or anything. I was coming back from a trip and noticed my Blue Sea ACR was disconnecting when I sat at a stop light. Its never done that before. It was a long interstate drive home and I didn't have any issues after that. Next morning I drove the cruiser to work and was getting some high volts on the scan gauge. Like 18 volts. My light on the gauge cluster was coming on as well . I can't find the photo but I had a picture of my negative battery terminal clamp. The end of the clamp where the threads are was melted. There was a small pool of metal on top of the battery from the clamp. I don't know if it was because of a bad connection or what. I replaced it and added a better ground on my aux battery to the body. Haven't had any trouble since then. I do need to upgrade all my grounds at some point. I've got a buzzing noise coming through my radio that comes and goes randomly. Turning the radio off makes the noise stop.... but then I can't listen to the radio.


My batteries are a Group 35 Sears DH Platinum and a group 31 Odyssey.

 

[DanMedeiros]

I seemed to have a similar issue awhile back. I didn't have any trouble with restarting or anything. I was coming back from a trip and noticed my Blue Sea ACR was disconnecting when I sat at a stop light. Its never done that before. It was a long interstate drive home and I didn't have any issues after that. Next morning I drove the cruiser to work and was getting some high volts on the scan gauge. Like 18 volts. My light on the gauge cluster was coming on as well . I can't find the photo but I had a picture of my negative battery terminal clamp. The end of the clamp where the threads are was melted. There was a small pool of metal on top of the battery from the clamp. I don't know if it was because of a bad connection or what. I replaced it and added a better ground on my aux battery to the body. Haven't had any trouble since then. I do need to upgrade all my grounds at some point. I've got a buzzing noise coming through my radio that comes and goes randomly. Turning the radio off makes the noise stop.... but then I can't listen to the radio.


My batteries are a Group 35 Sears DH Platinum and a group 31 Odyssey.

This is the exact symptom I have! I even had the radio buzzing noise before everything went crazy

 

[ThomasMore66]

Not to take away from this event, but did you see a bright light? Is God telling you something?

 

[Dissent]

When my scangauge read 20v it was my alternator dying. No EFI issues or melted terminals though.

 

[Mrtwooooo]

This is the exact symptom I have! I even had the radio buzzing noise before everything went crazy

Sure would like to fix my issue. Could be the factory ground cable for the main battery is getting old. Its a pretty small wire as it is.

 

[Dave 2000]

Get your garage to check the voltage sense cable, these are battery sensed systems, so the alternator is looking for a reference voltage, if there is a poor connection the alternator will ramp up the voltage, eventually bringing up the dash warning light. Could be as simple as a bad connection at the alternator plug?

I had a similar problem when swapping battery charge priority on my dual battery system, I had completely forgot about the cable. I swapped charge priority from cranking battery to auxiliary battery, this meant when the engine was running the alternator was sending charge to a battery that did not have a voltage sense cable. The results were as expected, the alternator went to maximum voltage. When I manually operated the Blue Seas ACR everything worked normally, the ACR would not click in on it's own due to the high voltage.

I am normally quite savvy with this stuff, so posted the query on MUD, plenty of suggestions none spot on but one was close enough to trigger the grey matter, and then the Eureka moment, I had forgotten to bring over the voltage sense cable.

So, voltage sense wire must go to the battery that is in constant connection with the alternator, the rewiring may have been connected to the wrong side of your battery changeover relay, easily done.

This would make sense if you were say sitting at a stop light, radio, lights heater whatever on, the changeover relay drops out as the battery voltage falls, the alternator is now isolated from the voltage sense wiring, so up goes the voltage.

Sorry for long post so hope it makes sense?

Regards

Dave

 

[DanMedeiros]

Thanks so much everybody! This community is freeking amazing! It was the fusable link. It was tight but I guess not tight enough. The shop who was working on it was way sheepish about it. Most likely their fault. Ended up purchasing an alternator i didn't need but hey now its good for another 20 years?