BlueBDA Posted May 23, 2020 Share Posted May 23, 2020 I have been through a lot trying to get my charging system working properly (BDA engine). First: My car stopped charging, due to there being only one bolt holding my alternator on (the one it pivots on, so the one to lock down the belt tension wasn't there). Ok, easy fix. Next: Belt was stretched just enough to make the alternator hit the steering shaft when trying to tighten the belt. So belt slipped, and strange vibration came through the steering wheel when I hit bumps. New belt fixed that. Now: Yesterday the volt meter read 12 volts, or even a bit below, when my wife and I went out for a ride. I noticed it and turned back home. Was definitely not charging, as it cranked slowly when I went to restart it. Today I checked it all over, looked over wiring, checked for continuity from alternator to battery + terminal. All seemed fine. Started it up, and voltage was 13-14 volts. Went for a 5 mile ride, and through that ride the volt meter fluctuated between approx. 12.0 and 15.5 volts. Not normal - right? Faulty voltage regulator? I had an alternator shop test the alternator a while back, and it was fine, but now I'm thinking that the voltage regulator is intermittent, and happened to work well when the alternator was tested. Should I just buy a new alternator? Anything else anyone can think of? :banghead: :bigear: Link to comment Share on other sites More sharing options...
SCse7en Posted May 23, 2020 Share Posted May 23, 2020 Do you have a good clean chassis to body to battery ground cable(s)? Link to comment Share on other sites More sharing options...
BlueBDA Posted May 23, 2020 Author Share Posted May 23, 2020 I'll check. By "body", do you mean the aluminum skin, or the frame? Do you have a good clean chassis to body to battery ground cable(s)? Link to comment Share on other sites More sharing options...
Anker Posted May 23, 2020 Share Posted May 23, 2020 Also, check that all connectors on the alternator are plugged fully in and tight! Link to comment Share on other sites More sharing options...
SCse7en Posted May 23, 2020 Share Posted May 23, 2020 By "body", do you mean the aluminum skin, or the frame? To the frame. Link to comment Share on other sites More sharing options...
BlueBDA Posted May 24, 2020 Author Share Posted May 24, 2020 I had three connectors to the alternator: Heavy cable that attaches to a stud with a nut, and two spade connectors. Based on this thread: http://www.usa7s.net/vb/showthread.php?12700-Ford-alternator-wiring&highlight=alternator and what someone told me when I called the company that makes the alternator, and what the guy who tested my alternator told me, I disconnected both of the spade connectors. Seems they were a legacy from the crossflow that used to be in this car. So there's just the bolted-on wire, and it's nice and tight. Also, check that all connectors on the alternator are plugged fully in and tight! Link to comment Share on other sites More sharing options...
BlueBDA Posted May 24, 2020 Author Share Posted May 24, 2020 This morning I checked the ground cable that goes from the engine block to the frame. Sanded the surface on the frame that it bolts to, to make sure there's no paint in the way. Cleaned and reattached. The cable was a little bit frayed at the crimp connector (though still plenty of strands intact), so at some point I'll replace that cable just to be certain. On my starter the terminal that the smaller wire (not the big red power cable) attaches to has some looseness. Hard to explain, but it looks like it is attached to the starter with solder, and the spade connector juggles around. So I fastened that down with a wire-tie, thinking that maybe a poor connection there is somehow affecting charging. Started it up and drove around the block. Volt meter read from 12.5 to 15 or so. At this point I'll take it our for a drive every day and notice what the volt meter says. Link to comment Share on other sites More sharing options...
BlueBDA Posted May 30, 2020 Author Share Posted May 30, 2020 (edited) I took a bunch of measurements today with my voltmeter, and here's what I learned: - Voltage gauge in the car reads 0.1 to 0.6 V lower than my multimeter (VOM). - Battery voltage (per my VOM) was 12.7-12.8 before starting. - Checked for parasitic current losses, and didn't detect any. - With engine running, before it warms up, voltage is around 12.5 at idle, and 14.0 or higher when revving. - MOST IMPORTANT: Once the engine warmed up, the voltage measured with VOM at the battery, and at the alternator + terminal, was 12.2. 12.0 with the lights on. Revving the engine did not budge this voltage - meter needle (yes - it's an old, non-digital VOM) did not move AT ALL. - NOTE: I did measure a voltage drop of 1.0-1.2V between the alternator + terminal and the battery + terminal when running cold. The scale on my VOM made it hard to read this, so I'm not 100% confident in this datapoint, but I did see the needle move a little. Once the engine warmed up this voltage difference went away - no needle movement at all. So - it charges when the engine is cold, but stops charging completely when warmed up. Bad alternator/voltage regulator? Other ideas? Edited May 30, 2020 by BlueBDA Link to comment Share on other sites More sharing options...
coffee break Posted May 30, 2020 Share Posted May 30, 2020 Is there an auto parts store near to you that has an alt. tester? I don't remember if you said anything about that earlier. Link to comment Share on other sites More sharing options...
BlueBDA Posted May 30, 2020 Author Share Posted May 30, 2020 I did have it tested at an alternator shop, and it was fine. But I realize now - it was cold. The problem occurs when the engine heats up. Link to comment Share on other sites More sharing options...
BlueBDA Posted May 31, 2020 Author Share Posted May 31, 2020 At this point I'm thinking I just need to buy a new alternator and hope that fixes this. It's very frustrating right now as I can't drive the car at all. Any other thoughts anyone before I pull the trigger on that? Link to comment Share on other sites More sharing options...
The Stig Posted May 31, 2020 Share Posted May 31, 2020 I’d say you found the problem after some methodical testing. New alternator time. Link to comment Share on other sites More sharing options...
ashyers Posted May 31, 2020 Share Posted May 31, 2020 If you're actually getting a voltage drop of over .5V in the alternator wire to the battery you should check that wire very carefully. Since you said that your meter was hard to read at that point and that the drop appeared to go away, maybe you're at the meters limits? I'd borrow a meter . It does sound like the alternator is toast if you're getting just a bit over 12V at the battery. I had one work fine cold and fail hot. It was irritating to diagnose, but sounds like you're nearly there. Link to comment Share on other sites More sharing options...
BlueBDA Posted June 1, 2020 Author Share Posted June 1, 2020 Thanks for the input everyone. New alternator on order. Hopefully that fixes this. Will update once installed. Link to comment Share on other sites More sharing options...
BlueBDA Posted June 7, 2020 Author Share Posted June 7, 2020 New alternator installed. Drove maybe 25 miles today, in hot weather, and volt meter read as it should at idle and at speed. So it's fixed. Yay. Last year the tensioning bolt fell out of the alternator, and I got stranded with a dead battery. Based on what the sheet that came with the alternator said, my theory is that when the belt was slipping it fried the alternator - more likely the voltage regulator. But whatever, I'm good now. And - I was finally initiated as a true Seven owner today, when my wife and I got caught in a thunderstorm 2 miles from home. We saw the storm coming, but ran an errand on the way home anyway, as I liked the challenge of beating the storm. Definite Type 2 fun. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now