At idle have 18.2 - 18.45 volts at idle on an old 83 Ford E250 with an external grill mounted voltage regulator. Thought it must be the voltage regulator, so changed that and it is still at 18.2 volts at idle. Could someone enlighten me as to what might be going on?

Thanks
mjac

 

dash gauge, or checked with a volt meter?

 

Couldn't be the Ford dash gauge. Even the 2009 f350 I drive at work doesn't have a meaningful volt or ammeter in the dash. Ford refuses to put numbers on their gauges.

Pull the F wire off the alternator. Tape it and then start it up and see what the voltage is. The F wire will be the orange/lightblue stripe wire going from the alternator to the regulator. Disconnect it at the alternator, in case it has melted into the large output wire.

 

Checked with Fluke 115 Multimeter. It was reading 18.2-18.4 at idle, also had a slow parasitic draw that would drop the battery from 13.2V to 11.1V overnight. Drove over to OReillys, took a reading at idle, read 12.90V, had them do a battery, starter, charging system test, twice, battery checked out, starter checked out, voltage regulater checked out, diodes checked out, starter failed twice, a NAAPA remanufactured 213-3017 that is two months old. This is the second one in 6 months. Thought the Fluke was giving wild numbers because of a low battery,mit was also reading “OL” at the beginning of the volt tests. But don’t know, have some new batteries coming.

Thanks
mjac

 

See above post, then does this still apply?

Thanks
mjac

 

I am not sure. You said you get 18v at idle, but O reilly's got 12.9 volts? That 12.9 is no good either unless the batteries were severely down on charge. Do you trust your meter? What does the meter say on the battery with the van off?

 

Can’t really explain what is going on, don’t know. Had a whole system in vehicle check at the same OReilys two weeks ago because I had a parasitic draw. Everything checked out good, battery, starter, alternator. Checked for s parasitic draw snd it read 0.00. Didn’t seem right being zero, checked the Fluke 115 and it has a blown amp fuse it appears. Waiting on a new one, so was just disconnection the positive terminal when off. Went to check the battery to see how much was lost, it was at 12.2 disconnected. Started up, checked battery, it was at 18.4. Changed voltage regulators, still at 18.2 - 18.4. Went to OReillys, checked battery while running with the Fluke, it was at 12.90. Orellys did the test, battery was at 12.8 running, battery checked out good, starter checked out good, voltage regulator checked out good, he said diodes checked out good, alternator failed. Went to NAPA where the reman alternator came from, they said they don’t check alternators. Went back to Oreillys and had them check it again, the exact same results. Ordered a new alternator from NAPA, just came in, will bring it to OReillys and have them bench test the new alternator, pull the old one, install new one, have them bench test the old one, which will be three checks before bringing it back to NAPA for warranty, it is only two months old and is a Ford OEM with a dedicated ground. Didn’t think it would give me any trouble. Then check the system and see what happens. Get a new fuse and battery for the Fluke and see if there is still a parasitic draw, might have been the alternator. The Fluke is consistent right now with battery disconnected. That is about it, that is as about much as I know right now. But you are right, that F post is awfully close to that hot lead, I can see how they could get fused if you are not careful. Will look at it when it is pulled.

Thanks
mjac

 

ALternator is bad, probably rectifier

 

Sometimes the F wire is wrapped in with other hot wires, like the output wire and the "A" wire going to the regulator. If they melt together, the F terminal gets 12v and that sends the alternator wide open charge. But I am not sure you should go down that path if O reillys got 12.9v. Or it could possibly be intermittent.

For the drain test, you can simply get yourself a testlight that has the old style bulb in the handle (not LED type). Take the battery negative off (you said batteries before, is this a diesel?). If you have two batteries take both negatives off. Lay them both on rags. Clip the testlight to the negative of the battery and jamb the sharp probe of the testlight into the neg terminal on the rag. If the testlight lights up bright you do have a drain.

Most vehicles have a drain. You have a older vehicle so it will be very low. If you have a modern digital radio with memory, or a fuel injection computer with memory, you will have a drain. It will usually be around .02 amps or so. The newer vehicles have a higher drain, but you never see it over .07 amps. These low amp drains flow through the testlight. But with the old time filament bulb in the testlight, it's not enough to light the bulb. If your testlight lights, then you do have a large enough drain to light the bulb. You can test it by opening the door. When the domelight comes on, the testlight will light.

 

P.S. If you do have two batteries, look to see if there are any little wires on one of them. From the factory my truck had no little wires on a pass side battery, all the smaller loads were on the driver's side. But when I added a trailer brake controller, I did hook it to the driver's side battery. So if you have anything connected to the other battery, it will need to be checked also with the testlight method.

Regardless, with two batteries, always disconnect both batteries to check amp draws.

 

It looks that way though I did not know why when OReilys said the diodes checked out good, didn’t know it could be the rectifier. This is my second one and it is a Ford OEM (Remanufactured) and lasted only two months .Don’t understand it. Just swap them out and see what happens I guess.

Thanks
mjac

 

No, just a single battery, so that does not apply. Right now I am just going to pull the old alternator and have it bench tested, that will be 3 tests, if it tests bad again, will bench tested the new alternator, if it tests good, put it in and see what happens. Have to wait on the fuse and battery for the Fluke 115 to check for draw.

Thanks
mjac

 

You are not going to believe this. I picked up the new Remanufactured Alternator from NAPA ( it was a Motorcraft too, just like the one in the truck that went bad in two months) and brought it right over to OReillys to have it bench tested…It Failed

 

I believe it. A good sign you have a bad part, is with the part replaced you have different problems or more problems than you started with.

I paid good money for a Cardone rebuilt distributor a couple years ago. Installed it, gave me trouble. Having gone through this over and over, I decided to take the rebuilt one apart. It was cleaned up on the outside, old grease and and filthy in the bearings on the inside, old pickup module, they hadn't done anything but clean it on the outside. I cleaned it up, installed a new pickup module, and it worked fine after that.

It happens over and over. You may decide "I am going to get a new alternator". Guess what? They are all made in China, you might get a good one, you might get a bad one. You can't blame Napa, all parts stores get their parts rebuilt or new from the same places.

It gives me a sick feeling when some guys rebuild their old trucks, and say "I am going to put all new in so it will not give me any trouble". And then they have horrible problems with it. If you have a OEM old part that works, keep it as long as possible.

 

This is the third one in about 2-3 years and the last two were Motorcraft…go figure. I have a sneeky feeling the Alternator was the patristic draw. Got the batteries today, waiting on the fuse for the Fluke 115.

Thanks
mjac