I’m trying to help someone diagnose a problem with their 1995 Ford Windstar. The van slowly dies when idling. It runs for a few seconds after being jumped and then the dash lights slowly dim after which the van stops running.
We replaced the battery and the van ran for about a day or so without issue. However, the problem is back. I suspected the alternator was faulty, so we pulled it and took it to a parts store to be bench tested. It was tested twice and passed both times. Does this sound like an alternator problem? Could there be an issue with the battery cables? What else might be causing this?
If this problem only occurs when the engine is idling then the Idle Air Valve could be suspect or there is a vacuum leak.
The quickest and easiest way to know if the latter exists is to connect a vacuum gauge to an intake manifold vacuum nipple.
If the problem was due to bad cables or connections, the van wouldn’t turn over even if it was jumped. With a new battery, a checked out and approved alternator, and an apparently good starter, what is left is a dead short to something unrelated to the ignition circuit.
Try running the van with nothing on and see how long it runs. If it doesn’t quit running, then try each circuit one at a time, lights, heat, A/C, whatever you have until the engine quits.
But it actually does just sound like an alternator with one or more dead diode. If you have a voltmeter or a AAA card, use the meter or the card to find out how much voltage your alternator is actually putting out. Triple A will not just come and jump your car, but measure the voltage to the battery and make a recommendation as to what your problem is.
All good suggestions. Thank you both. I forgot to mention in my original post above that the new battery that we installed last week has discharged completely. He has to jump it each time he attempts a start now. The old battery that we pulled exhibited the same problems. We replaced the battery because the van had been sitting for about five months until we were able to fix a brake problem, and we thought it needed one. I’ll experiment with the suggestions that you both have made and see if I can diagnose it further.
It does actually sound to me like a bad alternator. So since you’ve had that tested then I’d be looking at cables/connections. The battery’s connection to the van (e.g. grounds, starter) is apparently ok. But the alternator’s juice is apparently not making it anyplace. Trace all of those connections outward.
Thanks, cigroller. I’ll look into this.
Actually I should have mentioned that the quick way to tell whether you should spend any time there is just to put a voltmeter on the battery. Start the car and you should be reading anything between about 13.5 - 15V at the battery. If not, but the alternator bench tested ok, then I’d have to assume it is in the alternator’s connections.
This is turning into quite a mystery. The alternator is good. Had it tested again to be sure. We were using a jumpstarter to get the van running, and when we pulled the clamps, it would immediately die. We charged the battery again and I put a multimeter on it to check the voltage. It was about 11.5 volts at the time we tried starting again. When the car was started, there was absolutely no jump in voltage at the battery, so your statement about the alternator’s juice not going anywhere is accurate.
I tested the cables to see if we had a circuit and it looked good. Furthermore, I touched the multimeter to the cable connection on the alternator, and it registered in the same range as the battery–no voltage jump with the engine running. The van would run on its own for a while with the battery charged. However, it wouldn’t run for long since there is no apparent alternator function, and I could literally watch the voltage drop down to about 4-5 volts on the multimeter until the engine stalled. It was obvious that it was simply running from the already depleted battery.
I did notice that the smallest connector on the alternator did not seem to clip tightly in place. It’s fairly easy to pull off, which has me a little concerned.
While I was at the parts store getting the alternator tested, the guys there suggested that I look at the fusible link as a possibility. We looked at a wiring diagram and it apparently has two in the charging system circuit. I looked for them but couldn’t find them on this van. Does this sound plausible? If so, any idea of where they would be located on this vehicle?
With the key in the RUN position and the little red battery light on the dash illuminated you should feel a magnetic attraction when you touch the tip of a screwdriver to the alternator pulley. This is not always 100% definitive but generally means the alternator and the circuit that excites the alternator and makes it charge is good.
Since you have 11 something volts at the battery when running this would be normal considering the electrical draw of the running engine with no alt. output being put into the battery.
As per the guys who told you about the fusible link possibility, they’re probably right. Off the top of my head on a Windstar I can’t say for certainty where they’re located but generally near battery positive cable or branching from the starter solenoid terminal on vehicles with a fender mounted solenoid that is separate from the starter motor itself.
(The reason it could be dying after running for a while is that the 11 volts you see will continue to drop while the engine is running with no alt. output being provided into the battery. At some point when the voltage gets down around the 10 volt range the computer may be going stupid and shutting down.)
Thanks, ok4450. I’ll give this a try to see if I can detect any alternator activity.
From your description above I can’t tell what you were saying. But it almost sounded like you were saying that you were getting only about 11V at the alternator. That’s a bad alternator.
So just two simple questions.
- with the engine at idle, put the meter on the battery terminals. What do you get?
- Now check directly at the alternator. What do you get?
A healthy alternator should be putting out about 13.5-15V at idle. If all is well with connections & battery, you should read the same thing at the battery.