Instruments and car looses electricity while driving

[Thair92]

I have recently got a 1999 ford mustang base started that have been sitting for around 3 years, I had to replace the fuel pump. after the first drive I notice two problems:

1- The car is loosing electricity and I can tell by the way the instrument gauges reset while the car is running and even while driving.

2- the fuel gauge seems to not getting any readying at all but when I first turned the car one after replacing the pump it worked but now nothing, not sure if this is related to the first problem

 

[3.14159]

Well considering your alternator isn’t charging I’m surprised the car is running at all.

 

[01yellercobra]

Check all the grounds first. How old is the battery? I've had a bad battery cause some weird issues. And the gauges sweeping each time is usually a big symptom. As for the fuel gauge there are chances the arm fell off or something else happened after you drove it.

 

[Burninriverdiver]

A bad alternator causes funny symptoms like that, I'd second that recommendation

 

[ttocs]

How many volts with the key off?
How many volts with the engine running?
Don't bother with the stock gauge stick a meter on it.

 

[Michael Soldan]

I had a bad battery in a Firebird do the same thing. It would start the car but gauges wouldn't work properly and the car didn't perform as it should, very sluggish. Replaced the battery and the car was good to go.

 

[Thair92]

How many volts with the key off?
How many volts with the engine running?
Don't bother with the stock gauge stick a meter on it.

I used a multimeter, with the car off, the battery gave around 12.6 which is normal, then started the car and it gave around 14V which is also I guess normal since the alternator is charging.

I also noticed that when I give the car some gas and try to reach more than 3000 rpms, the battery gauge moves to "H" and goes back to normal when I release the gas pedal.

 

[3.14159]

Could be corroded connections on the alternator or maybe it just needs replacing.

 

[ttocs]

I would pull out the gauge cluster and inspect the connections.

 

[evilcw311]

I used a multimeter, with the car off, the battery gave around 12.6 which is normal, then started the car and it gave around 14V which is also I guess normal since the alternator is charging.

I also noticed that when I give the car some gas and try to reach more than 3000 rpms, the battery gauge moves to "H" and goes back to normal when I release the gas pedal.

This sounds like the regulator is bad in your alternator. It’s causing the voltage to spike when you rev it. After it spikes and comes back down the cluster will sometimes reset.

I had this happen in my 95. After it spiked a few times the battery boiled over. Throw A meter on the battery and have someone hit 3k rpms. See what it reads. Mined spiked up to 23v


Sent from my iPhone using Tapatalk

 

[MyLittlePony]

Battery, alternator, or what connects the two. This happened to me once and I had just enough juice to get me to my dentist appointment. Radio died and everything. After my appointment, I was given a compliment on the car, and immediately had to ask the same person for a jump (how embarrassing.) The battery simply would not hold whatever charge it was getting. I had my husband drop by with an extra alternator that I had, and we installed it and got a new battery for it. Car was able to make it the same distance home before everything started failing again. What are the odds that both alternators, and both batteries (old one was only a month or two old) were bad?

Eventually we discovered that the wiring connecting to the fuse box had corroded off. Alternator wasn’t charging the battery, and the battery was the only source of power until it ran dead. Fixing the connection, it never did it again.