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08-16-2022, 12:40 PM | #1 |
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Can ammeter cause trouble?
Friend has had a problem with his '30 coupe deciding to stop on it's own without warning. We've been through the fuel and electrical system and everything looks OK. I noticed that his ammeter was not registering and he told me it's never worked right. Can a bad ammeter affect the way a car runs or is it just a gauge?
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08-16-2022, 12:51 PM | #2 |
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Re: Can ammeter cause trouble?
Yes. Even loose connections.
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08-16-2022, 01:03 PM | #3 |
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Re: Can ammeter cause trouble?
All power on the car, except for the starter, passes through the ammeter – in one side and out the other. This includes flow to the lights, distributor, and charging the battery. If the ammeter connections are bad, the car won't run.
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08-16-2022, 02:57 PM | #4 |
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Re: Can ammeter cause trouble?
And it don't either.
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08-16-2022, 03:11 PM | #5 |
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Re: Can ammeter cause trouble?
There are two sources of power in a model A. The battery and the generator. What the amp meter indicates is the difference in flow between the load side (generator) and the battery side. Some of the reproduction amp meters are crap and some will work to a certain degree. The original Ford ammeters are by far the best.
I agree on connections. They should be checked periodically to insure they are clean and tight. Also, keep a spare condenser around at all times. They will die from heat injury at any time. The motor may run with a bad condenser but it won't run well. Ford didn't protect their wiring very well. There are several places where folks can have shorts due to wire runs wearing against parts of the car that are directly grounded to the frame. These areas should have more insulated wire loom. A fuse kit on the starter is a must. Last edited by rotorwrench; 08-16-2022 at 03:23 PM. |
08-16-2022, 06:27 PM | #6 |
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Re: Can ammeter cause trouble?
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I investigated and found the two nuts on the ammeter were not in the slightest tight and both leads were just swinging free on the posts. I suspect the mechanic that installed the ammeter forgot to tighten the nuts. What was going on was two resistance contacts that generated heat and boiled the moisture off in the mornings. An easy fix, tighten the nuts. Tom Endy |
08-16-2022, 07:34 PM | #7 |
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Re: Can ammeter cause trouble?
Thanks for the posts. I guess we need to find a new ammeter. In checking I find that it's hard to find a good ammeter. Any suggestions?
Marty |
08-16-2022, 08:09 PM | #8 |
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Re: Can ammeter cause trouble?
Check with Dale G., he rebuilds them.
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08-16-2022, 08:36 PM | #9 |
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Re: Can ammeter cause trouble?
First thing I would do is take the panel off and check the back of the ammeter. It might be an easy fix. You never know what kind of hack the guy before you tried. Make sure the wires are routed correctly, the nuts are tight, and the insulating spacers are in good condition. Check the terminals for resistance. You can remove it from the panel by bending up the bezel tabs (or sometimes the gauge just comes right off the bezel). Once it's off, you can test it by putting it inline with various currents, e.g., a horn that you have on the bench, or between a charger and a battery.
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08-16-2022, 10:09 PM | #10 |
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Re: Can ammeter cause trouble?
Paul Shinn recently released a new YouTube video on his channel about soldering the internal connections on new repro ammeters to make them safe (id - non fire hazard) to use.
An alternative is to find a good used ammeter - either an original, or an older reproduction unit with a brass case. New face plates and glass lenses are available, if needed. Good luck - Jim |
08-17-2022, 05:16 AM | #11 |
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Re: Can ammeter cause trouble?
To aid quick diagnosis I'm a great believer in hotwiring to help eliminate and trace possible short circuits/open circuits. OK you may need a new ammeter but IMHO that's unlikely to be the cause of "...deciding to stop on it's own without warning.." as I asume that's a new problem and the .." ammeter was not registering and he told me it's never worked right..." is an old one. Diagram below. (in your case you might want to remove the yellow wire from the starter sw just to eliminate the ammeter and associated wiring completely )
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08-17-2022, 08:19 AM | #12 |
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Re: Can ammeter cause trouble?
Can anyone here tell me why all the repo ammeters that are sold
are cheap and junky? Makes no sense to me at all. This is important. Almost as bad as those caged rollers bearings being of not the greatest quality! You can't keep listening to people that complain about the cost of parts . |
08-17-2022, 08:46 AM | #13 |
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Re: Can ammeter cause trouble?
I had my ammeter /wiring start smoking one afternoon.. Very disconcerting to see a fair amount of acrid grey smoke coming from the dash!
Turns out the ammeter nuts were heat damaged [over time] the wiring connectors as well.. and the ammeter studs themselves were loose inside the ammeter too. I am sure this condition was y e a r s in the making. I since have cleaned the connections, replaced those affected wiring harnesses, the nuts too & secured the ammeter threaded studs. All seems well once more. Oh, and I bought a reproduction ammeter just in case.. Well the ammeter nuts from it did NOT fit the original, and as stated above, it seemed poor quality overall. My car has a LOT of time worn 'patina' which I rather like.. so the original will stay in place while functional.... M |
08-17-2022, 10:06 AM | #14 |
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Re: Can ammeter cause trouble?
One problem on lot of ammeters I've opened up is the internal insulator on the shunt bar is generally just a fiber material a lot like paper but a bit thicker. The case insulators or the nuts are not a problem unless they get hot and melt a bit. This just makes the connections loose. The plastic coated nuts may have seemed to be a good idea but metal nuts with thin lock washers might be better. They likely used the plastic covered terminal nuts for better insulate the terminal ends against possible shorts on the inside of the panel.
Modern replacements just don't have the quality that the original meters had. The larger separate horse shoe magnet seems to make the indicator needle a lot more sensitive than the current types that have the tiny magnet on the armature. The one I have on my 1956 850 Ford tractor is a cheapy too but it will tell me that it's charging at least. Finding good quality small indicator devices like this is almost impossible in the modern era. Ford put those funky brass half wing nuts on the terminal box for a reason. A person can bypass the ammeter by putting an alligator clip type jumper wire between those two terminal box nuts. A person can also use them for other troubleshooting procedures. Last edited by rotorwrench; 08-17-2022 at 10:13 AM. |
08-17-2022, 10:34 AM | #15 |
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Re: Can ammeter cause trouble?
Ditto
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08-17-2022, 11:25 AM | #16 | |
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Re: Can ammeter cause trouble?
Quote:
I think I would pull the dash first to investigate the situation.
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08-17-2022, 05:29 PM | #17 |
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Re: Can ammeter cause trouble?
I agree that the new replacements are not good. Several years I bought one from Snyder's and the needle fell off the post before I ever got it in the car. I took it apart and put the needle back on and it fell off again. I called Snyder's and they refunded the money. I offered to send the "new" replacement back and they told me to just throw it away. They weren't worth the postage to send it back.
Marty |
08-17-2022, 05:34 PM | #18 | |
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Re: Can ammeter cause trouble?
Quote:
Mine was from Snyders as well. |
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08-17-2022, 07:54 PM | #19 |
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Re: Can ammeter cause trouble?
IMO, we are our own worst enemy when it comes to the vendors selling junk. Too many car owners are too tight assed to pay for quality so the vendors would be stuck with it but they can sell a cheaper (read trashy) item so that's what they stock. I have always believed that buying junk is more expensive than buying a decent item in the first place. For example, those ammeters that didn't even last long enough to be fitted into the dash were a TOTAL waste of money, that is zero value whereas, if a decent one were available and bought, the car owner would be getting value out of it for years. I'm not saying those guys are tight asses, just that there was probably no other option.
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08-23-2022, 06:36 AM | #20 |
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Re: Can ammeter cause trouble?
I had an ammeter short on the back, touching the gas tank.
an easy check....... |
08-23-2022, 06:56 AM | #21 |
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Re: Can ammeter cause trouble?
The ammeter has an area of trouble.
The 2 studs are drawen down tight to the bus bar on the inside of the meter. All the current flows along this bar to make the magnetic field to deflect the needle. The trouble comes with a problem between the studs and the bus bar. On original ammeters this is mostly from corrosion if moisture gets in, but they tend to be ok because the copper is a better quality. The reproductions use a lower grade of brass for the bus bar. They tend to get corrosion which increases resistance and creates heat. The fix is kind of simple, but needs careful soldering skills. You need to lightly tin and the bus bar and stud. Then sweat them together. The difficulty is keeping the stud close to the bus bar, you need it touching. While my original meter had good connections, I still soldered them. In the end this will slightly reduce resistance which can only help the system. I will note that I am very skilled in electronics soldering and very picky how I do things. I would recommend that you practice soldering some before tackling the real meter you intend to use. |
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