brandonsmash
SMASH!
- Joined
- Aug 19, 2015
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- Location
- Phoenix, AZ, USA
- Vehicle(s)
- 2015 GT - PP
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- #1
I've been on this forum for a while but have been inactive for a bit. My apologies.
TL;dr: '15 GT with an odd no-start/no-charge/no-jump.
Recently I've noticed that my '15 GT (18,600 miles) had been getting slightly slower to start. I installed a battery tender pigtail because I was going to be gone for the month of July.
I came back and the car started and drove normally through August, but I wondered about the charging system; the voltage display on the dash read ~13.9V. I have not had any CELs or warnings on the dash.
On Wednesday I had a job call on the other side of town and I drove the Mustang (which started maybe a touch slowly, but without real problem). I stopped to check in at security for the location and was cleared to proceed, but the car wouldn't start at all. It would crank once (slowly) and then go dark.
Attempt 1 was a jumper pack. No luck.
Attempt 2 was a guy with a truck. The truck was equipped with a 180A alternator and dual batteries. Still no luck. I pulled the positive battery cable and cleaned it, and connected the jumper cables (4AWG welding cable) directly from the good battery to the positive battery cable (without using my battery at all) and the frame. No luck -- same thing.
Attempt 3 was the guy that Ford Roadside Assistance sent out. He hooked up two jump packs AND his running car. Still no luck.
At this point I called for a tow and had the Mustang towed to the dealer where I bought the car.
The next day the dealer called and told me that they'd replaced the battery and that everything else was fine. The service advisor told me the car "started right up" for her before even replacing the battery, and that the battery had a shorted cell. I asked them to test the alternator; she said it was at 14.2 volts. The replacement battery cost me $197. (The vehicle is under an extended service plan but the battery is not covered.)
(Okay, yes, a bad battery can sometimes revive itself after sitting for a while, yes, but a battery with a shorted cell can never do this: If a cell is shorted, all the current will always take that path to ground.)
The tech blamed my battery tender pigtail for causing the fault, disregarding that I used factory ring terminals on the pigtail and it was installed directly to the OEM accessory posts and was installed after I had my first slow start.
Driving home yesterday I checked the voltage using the dash display; it read 13.6V, not the 14.2 they'd claimed.
This morning the car started fine and I drove to work. The dash display read 12.7 to 13.3V irrespective of RPM, load, and driving condition. I popped the hood once at work and checked the (running) pole-to-pole voltage with two multimeters, both of which read 13.3V.
I called the dealer again and asked what the alternator was putting out. The service advisor confirmed 14.2V. I mentioned that I had photos of the voltage as between 12.7 and 13.3 under running conditions. She came back after a minute and then told me that her tech said that "anything above 13.1 was okay" because the alternator is controlled by the PCM. She did not address the fact that she specifically told me that the alternator was measured at 14.2V before I tested it myself.
I phoned another dealership. Their SA told me that they like to see between 13.5-14.5V.
Here's where I'm confused. For one, I thought that an automotive battery was comprised of 6 cells of 2.3V each and so required 13.8V to charge at all.
For another, I don't understand why the vehicle wouldn't start even with the positive terminal disconnected from the battery and attached to another (good) battery and the negative lead of the other battery clamped directly to the frame of the Mustang. After the 3 jump attempts it sat in that spot for 6 hours and wouldn't take a jump or even get enough power to unlock the doors.
So am I being paranoid? Has my understanding of batteries and charging systems become outdated? Am I overlooking something with regards to the no-jump condition?
Apologies for the long post; I thought details may be merited here.
Cheers!
TL;dr: '15 GT with an odd no-start/no-charge/no-jump.
Recently I've noticed that my '15 GT (18,600 miles) had been getting slightly slower to start. I installed a battery tender pigtail because I was going to be gone for the month of July.
I came back and the car started and drove normally through August, but I wondered about the charging system; the voltage display on the dash read ~13.9V. I have not had any CELs or warnings on the dash.
On Wednesday I had a job call on the other side of town and I drove the Mustang (which started maybe a touch slowly, but without real problem). I stopped to check in at security for the location and was cleared to proceed, but the car wouldn't start at all. It would crank once (slowly) and then go dark.
Attempt 1 was a jumper pack. No luck.
Attempt 2 was a guy with a truck. The truck was equipped with a 180A alternator and dual batteries. Still no luck. I pulled the positive battery cable and cleaned it, and connected the jumper cables (4AWG welding cable) directly from the good battery to the positive battery cable (without using my battery at all) and the frame. No luck -- same thing.
Attempt 3 was the guy that Ford Roadside Assistance sent out. He hooked up two jump packs AND his running car. Still no luck.
At this point I called for a tow and had the Mustang towed to the dealer where I bought the car.
The next day the dealer called and told me that they'd replaced the battery and that everything else was fine. The service advisor told me the car "started right up" for her before even replacing the battery, and that the battery had a shorted cell. I asked them to test the alternator; she said it was at 14.2 volts. The replacement battery cost me $197. (The vehicle is under an extended service plan but the battery is not covered.)
(Okay, yes, a bad battery can sometimes revive itself after sitting for a while, yes, but a battery with a shorted cell can never do this: If a cell is shorted, all the current will always take that path to ground.)
The tech blamed my battery tender pigtail for causing the fault, disregarding that I used factory ring terminals on the pigtail and it was installed directly to the OEM accessory posts and was installed after I had my first slow start.
Driving home yesterday I checked the voltage using the dash display; it read 13.6V, not the 14.2 they'd claimed.
This morning the car started fine and I drove to work. The dash display read 12.7 to 13.3V irrespective of RPM, load, and driving condition. I popped the hood once at work and checked the (running) pole-to-pole voltage with two multimeters, both of which read 13.3V.
I called the dealer again and asked what the alternator was putting out. The service advisor confirmed 14.2V. I mentioned that I had photos of the voltage as between 12.7 and 13.3 under running conditions. She came back after a minute and then told me that her tech said that "anything above 13.1 was okay" because the alternator is controlled by the PCM. She did not address the fact that she specifically told me that the alternator was measured at 14.2V before I tested it myself.
I phoned another dealership. Their SA told me that they like to see between 13.5-14.5V.
Here's where I'm confused. For one, I thought that an automotive battery was comprised of 6 cells of 2.3V each and so required 13.8V to charge at all.
For another, I don't understand why the vehicle wouldn't start even with the positive terminal disconnected from the battery and attached to another (good) battery and the negative lead of the other battery clamped directly to the frame of the Mustang. After the 3 jump attempts it sat in that spot for 6 hours and wouldn't take a jump or even get enough power to unlock the doors.
So am I being paranoid? Has my understanding of batteries and charging systems become outdated? Am I overlooking something with regards to the no-jump condition?
Apologies for the long post; I thought details may be merited here.
Cheers!
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