My 97 Escort wagon has started acting on occasion like it has a faulty alternator. I can start a trip with 14 volts on the battery then after some miles it stops charging and eventually the car quits. I can come back to the car later and after jumping it, it will show 14 volts again on the battery with the engine running.

A few minutes ago I went out to the car. Battery voltage with engine off was right at 13 volts but dropped to 12.5 after starting the engine. Went for a 1 mile drive. When I got home battery voltage was back up to 14.

Can an alternator be intermittent or should I be looking for a wiring problem? AdvanceAuto Parts said that the alternator was ok but half an hour later the car was dead again.

 

Sometimes the plugs going on the alt can have connection problems where the connections become intermittent because the terminals in the plug are too loose. Might want to confirm good tight connections there.

 

What's the best way to tighten those connections?

 

The best way is to replace the plug, most auto supply stores usually have the replacement plugs. All you need to do is splice in the new plug.

 

Problem is not yet solved. I replaced the plug at the alternator, cleaned the single wire plug at the alternator and cleaned all of the connections at the battery. Even swapped the alternator. Sometimes the voltage at the battery is 14, sometimes it's 12.5 and creeps down with the headlights on. Then when I turn the engine off, battery voltage will go to near 13.

I'm at a loss for ideas.

 

Best to start from the beginning,
What is the condition of the battery, Has it been tested?
That has to be confirmed before doing anything else.

 

I will take it in tomorrow for testing. The battery does start my 1964 Rambler and it does stay charged in that car.

 

What is the voltage at the battery when the vehicle won't start? Will the headlites come on?
If the voltage is at least 12 volts , that should be enough to start the engine.
When you say the car was dead a half hour later , that can be caused by a poor connection either because the cables are corroded internally , the connections that the cables are making at the other end where they are connected to the engine and sheet metal. If the alt tested good and the battery tests good, there has to be a corroded/poor connection problem. They do not always look bad , but can look good and still offer enough resistance to prevent the alt from fully charging the battery or preventing the vehicle from starting once warmed up.
When you state the vehicle was dead, exactly what result were you getting ?
Did it just click, do absolutely nothing , need to know that.

 

When the car died, the voltage was under 9 volts. The lights were dim. The radio wouldn't work and the starter would only click once or twice.

I disconnected and cleaned every ground connection from the battery and alternator I could find and bought a new cable to run from the battery to the body. 10 minutes into a test drive and the voltage dropped from 14.2 to 12.6 and stayed that way until I got to the parts store. They ran their in in car testing gadget and said that the battery was good but it wasn't charging.

Took the alternator off of the car in the parking lot. (Had to work with gloves on because it was so hot.) They tested it and it tested good on the machine but said that since it had about 20 minutes or so to cool, it could have fixed itself. They gave me another alternator to try which I installed in the parking lot.

24 hours later and the voltage now stays in the 14.2 to 14.4 range. Is the car fixed? I won't be sure until it continues to operate correctly for at least a week.