Go Back   The Ford Barn > General Discussion > Model A (1928-31)

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Display Modes
Old 07-11-2018, 09:24 PM   #1
Dave1929
Junior Member
 
Dave1929's Avatar
 
Join Date: Jun 2018
Location: Westphalia, Texas
Posts: 24
Default Coil has constant power

I have a 1929 Tudor without cowl lights. I have been running this car for a couple weeks and today it wouldn't start. No spark is what I found. I have noticed that no matter if the ignition switch is off or on I have a full 6v to the coil. Did this burn my coil out which equals no sparky? What would cause constant voltage to the coil? The ignition switch bench tests good. Is it possible a wire got switched around and it has just taken this long for the coil to finally give out? The coil looks old but that doesn't mean it wasn't put on right before I bought the car. Also I noticed I have a full 6v to the generator when the car is not running. Is this right?
Dave1929 is offline   Reply With Quote
Old 07-11-2018, 09:31 PM   #2
steve s
Senior Member
 
steve s's Avatar
 
Join Date: May 2010
Location: Kalamazoo
Posts: 1,588
Default Re: Coil has constant power

Yes, the coil is always connected to the battery. It's no more of a problem for the wires IN the coil than it is for the wire ON THE WAY to the coil, as long as there is no current flow. If the ignition key/switch is good, there will be no current flow and no possible harm UNLESS there's a short, which will show up more spectacularly elsewhere, or, at the very least, a dead battery!

CHeck for loose connections in the primary ignition circuit--the connections to the ammeter or the ammeter itself are frequent culprits. Putting a jumper wire (e.g., alligator clip leads) across the two junction box wing nuts will bypass the ammeter and permit an easy test without pulling the dash panel, ASSUMING the car has original wiring setup. Another notorious actor is a "pigtail" wire in the bottom of the distributor, which tends to short out to ground after rubbing against the distributor base a million times during spark advance/retardings.

Otherwise, condensers regularly go bad and less frequently coils do too. Typically, when either of these fail you get weak spark and crappy running rather than total absence of spark. Google or Search for test procedures or try another one.

Last edited by steve s; 07-11-2018 at 09:49 PM.
steve s is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 07-11-2018, 09:38 PM   #3
midgetracer
Senior Member
 
midgetracer's Avatar
 
Join Date: May 2010
Location: Bismarck ND
Posts: 725
Default Re: Coil has constant power

Steve is right. Also 6V to the generator is correct on the cutout side of the generator. 6V on the generator side of the cutout would be bad and indicate that the cutout is not working.
midgetracer is offline   Reply With Quote
Old 07-11-2018, 09:56 PM   #4
eagle
Senior Member
 
eagle's Avatar
 
Join Date: Aug 2011
Location: Eagle Bend, MN
Posts: 1,262
Default Re: Coil has constant power

Turn on the ignition switch, as you slowly turn the engine over with the crank, the point side of the coil should go to ground. If its not, check points/ignition switch/etc. Easy to trace with a voltmeter.
__________________
"There are some that can destroy an anvil with a teaspoon and shouldn't be allowed to touch anything resembling a tool."
eagle is offline   Reply With Quote
Old 07-11-2018, 10:09 PM   #5
Dave1929
Junior Member
 
Dave1929's Avatar
 
Join Date: Jun 2018
Location: Westphalia, Texas
Posts: 24
Default Re: Coil has constant power

This car was running good the day before yesterday. It has been cutting out a bit under a load. Today I did replace the a meter with a new one because the old one was no where near calibrated as in the needle was way off of zero. I have bypassed the new ammeter and there is still no spark. I did emery cloth the points just a bit to clean them up but other than that I've done nothing today. I pull the main wire from the top of the distributor and hold it close to ground while cranking and there is no spark still yet. I'm thinking my coil just took a dump.
Dave1929 is offline   Reply With Quote
Old 07-11-2018, 10:15 PM   #6
eagle
Senior Member
 
eagle's Avatar
 
Join Date: Aug 2011
Location: Eagle Bend, MN
Posts: 1,262
Default Re: Coil has constant power

Quote:
Originally Posted by Dave1929 View Post
This car was running good the day before yesterday. It has been cutting out a bit under a load. Today I did replace the a meter with a new one because the old one was no where near calibrated as in the needle was way off of zero. I have bypassed the new ammeter and there is still no spark. I did emery cloth the points just a bit to clean them up but other than that I've done nothing today. I pull the main wire from the top of the distributor and hold it close to ground while cranking and there is no spark still yet. I'm thinking my coil just took a dump.
DON'T start replacing parts until you find out what is wrong. Use a voltmeter and a wiring diagram and go through it step-by-step. If you start throwing parts at it you will introduce issues and it will make it much harder to troubleshoot. 6V on both side of the coil is normal. The point side of the coil goes to 0v only when points are closed and ignition switch is ON.
__________________
"There are some that can destroy an anvil with a teaspoon and shouldn't be allowed to touch anything resembling a tool."
eagle is offline   Reply With Quote
Old 07-11-2018, 10:40 PM   #7
Dave1929
Junior Member
 
Dave1929's Avatar
 
Join Date: Jun 2018
Location: Westphalia, Texas
Posts: 24
Default Re: Coil has constant power

I've traced voltage from the battery, to the fuse on the starter, to the coil, to the ignition switch and back. What would cause the coil to not put out? I'm rechecking the points now. Nothing has been changed but I'm gonna recheck.
Dave1929 is offline   Reply With Quote
Old 07-11-2018, 10:55 PM   #8
Dave1929
Junior Member
 
Dave1929's Avatar
 
Join Date: Jun 2018
Location: Westphalia, Texas
Posts: 24
Default Re: Coil has constant power

So this is what I found. The point gap is .020. The ignition side of the coil does go to ground when the points close. When the points open with the key on there is a very pronounced spark. Ideas?
Dave1929 is offline   Reply With Quote
Old 07-11-2018, 11:55 PM   #9
Tom Wesenberg
Senior Member
 
Tom Wesenberg's Avatar
 
Join Date: May 2010
Location: Mpls, MN
Posts: 26,881
Default Re: Coil has constant power

Key On, engine stopped with points open. Now short the points contacts off and on with a screwdriver while holding the coil wire 1/4" from a head nut. Do you have spark?
Tom Wesenberg is offline   Reply With Quote
Old 07-12-2018, 08:35 AM   #10
Dave1929
Junior Member
 
Dave1929's Avatar
 
Join Date: Jun 2018
Location: Westphalia, Texas
Posts: 24
Default Re: Coil has constant power

No.
Dave1929 is offline   Reply With Quote
Old 07-12-2018, 08:35 AM   #11
Dave1929
Junior Member
 
Dave1929's Avatar
 
Join Date: Jun 2018
Location: Westphalia, Texas
Posts: 24
Default Re: Coil has constant power

I'm going to pick up a new coil and condenser today.
Dave1929 is offline   Reply With Quote
Old 07-12-2018, 08:39 AM   #12
Dave1929
Junior Member
 
Dave1929's Avatar
 
Join Date: Jun 2018
Location: Westphalia, Texas
Posts: 24
Default Re: Coil has constant power

I guess the reason for my initial question was why would the coil have voltage constantly. It is just a different setup than all the antique tractors I have worked on. When the ignition switch is off there is no voltage to the coil. I was always under the impression that voltage to the coil constantly would burn it out. I guess I was wrong because the way the A is laid out there is always voltage there.
Dave1929 is offline   Reply With Quote
Old 07-12-2018, 08:40 AM   #13
eagle
Senior Member
 
eagle's Avatar
 
Join Date: Aug 2011
Location: Eagle Bend, MN
Posts: 1,262
Default Re: Coil has constant power

Quote:
Originally Posted by Dave1929 View Post
So this is what I found. The point gap is .020. The ignition side of the coil does go to ground when the points close. When the points open with the key on there is a very pronounced spark. Ideas?
Now you're getting somewhere. With points closed, the coil should have 6 v on one side, zero on the other kids (relatively close anyway) if still no spark out of coil, then yes, bad coil. However, I would do as Tom suggested, short across open points, watch for spark.
__________________
"There are some that can destroy an anvil with a teaspoon and shouldn't be allowed to touch anything resembling a tool."
eagle is offline   Reply With Quote
Old 07-12-2018, 08:56 AM   #14
cpf240
Senior Member
 
cpf240's Avatar
 
Join Date: Feb 2017
Location: Northern Idaho
Posts: 247
Default Re: Coil has constant power

Quote:
Originally Posted by Dave1929 View Post
I guess the reason for my initial question was why would the coil have voltage constantly. It is just a different setup than all the antique tractors I have worked on. When the ignition switch is off there is no voltage to the coil. I was always under the impression that voltage to the coil constantly would burn it out. I guess I was wrong because the way the A is laid out there is always voltage there.
But on a stock A, the circuit is not completed unless the ignition key is on and the points are closed. So no current flows until then, no burnt out coil. The switch is just in the ground leg of the circuit, rather than the hot leg.
cpf240 is offline   Reply With Quote
Old 07-12-2018, 09:33 AM   #15
katy
Senior Member
 
katy's Avatar
 
Join Date: Jun 2015
Location: Alberta, Canada
Posts: 1,377
Default Re: Coil has constant power

Quote:
When the points open with the key on there is a very pronounced spark.
That suggests a bad condensor.
__________________
Talk slow, think fast.
katy is offline   Reply With Quote
Old 07-12-2018, 10:34 AM   #16
Dave1929
Junior Member
 
Dave1929's Avatar
 
Join Date: Jun 2018
Location: Westphalia, Texas
Posts: 24
Default Re: Coil has constant power

So I came out to the shed today. All the testing I did yesterday was in the evening and keep in mind it was 103 degrees today. No spark at all. Grounding the points, nothing from the coil. Came out to the shed this morning. It's in the upper 80s temp wise, nice morning. I was fixing to take the coil off to take it to the parts house and figured "what the heck" I'll try it one more time. Son of a gun fired right up. What gives? The only think I can think of is bad coil and/or condenser. As cheap as they both are I'm replacing them both. I have had an inkling thinking the coil was getting weak because at loads and after the car is hot it has been cutting out a bit.
Dave1929 is offline   Reply With Quote
Old 07-12-2018, 10:35 AM   #17
Dave1929
Junior Member
 
Dave1929's Avatar
 
Join Date: Jun 2018
Location: Westphalia, Texas
Posts: 24
Default Re: Coil has constant power

103 yesterday, not today yet.
Dave1929 is offline   Reply With Quote
Old 07-12-2018, 11:04 AM   #18
barnstuf
Senior Member
 
Join Date: May 2010
Location: Cape Cod MA
Posts: 2,398
Default Re: Coil has constant power

In your second post you said you replaced the meter because its calibration was way off. I assume you mean ammeter and it may have shown a substantial discharge because the cutout points were stuck. This would kill the battery. When it started at a later time maybe the cutout points were no longer closed. Also any time you file the points run a pice of paper between them to clear debris. The old timers found a paper matchbook cover to be ideal.
barnstuf is offline   Reply With Quote
Old 07-12-2018, 11:07 AM   #19
Dave1929
Junior Member
 
Dave1929's Avatar
 
Join Date: Jun 2018
Location: Westphalia, Texas
Posts: 24
Default Re: Coil has constant power

The ammeter was showing wrong because when I was fixing the gas gauge it fell out onto the concrete floor not because there was a discharge. My battery hasn't gone dead at all.
Dave1929 is offline   Reply With Quote
Old 07-12-2018, 12:36 PM   #20
DHZIEMAN
Senior Member
 
Join Date: Dec 2016
Location: Sunrise Beach, Mo
Posts: 164
Default Re: Coil has constant power

There is a need to get to the cause! That takes a bit of effort with a voltmeter and an ohm meter! You can also set up a little test bench with 6 volts applied on the coil, with a condenser across the connection wires and open the wires (what maybe a paper clip in the center high voltage port to one of the terminals, and when you open the wire if you can get a good solid quarter inch spark, you coil and capacitor are OK. If not, it is one or the other, Coil or capacitor. If it is not the coil or capacitor, then you need to reinstall, and start checking with a voltmeter for continuity and open circuits not getting power and ground to the coil. Good luck
DHZIEMAN is offline   Reply With Quote
Old 07-12-2018, 01:21 PM   #21
Tom Wesenberg
Senior Member
 
Tom Wesenberg's Avatar
 
Join Date: May 2010
Location: Mpls, MN
Posts: 26,881
Default Re: Coil has constant power

I would NOT replace the coil or condenser.
I'd look at the short black wire under the top plate in the distributor. If that is good, then look for the popout cable to be screwed in too far or bad along it's length.


BTW, today's gas boils way easier than the good gas of the 60's, and this will cause problems on hot days with carbureted engines.
Tom Wesenberg is offline   Reply With Quote
Old 07-12-2018, 01:22 PM   #22
Dave1929
Junior Member
 
Dave1929's Avatar
 
Join Date: Jun 2018
Location: Westphalia, Texas
Posts: 24
Default Re: Coil has constant power

I'm fixing to install my new 6v coil and new condenser. I'll post what happens then. All the arrows point to a bad coil/condenser. Seeing as how the both of them together cost less than a steak at Texas Roadhouse, I'm ok with replacing both.
Dave1929 is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 07-12-2018, 01:23 PM   #23
Dave1929
Junior Member
 
Dave1929's Avatar
 
Join Date: Jun 2018
Location: Westphalia, Texas
Posts: 24
Default Re: Coil has constant power

Tom this problem seems to be an intermittent problem. One day it worked well then next day it didn't then the next day it worked again.
Dave1929 is offline   Reply With Quote
Old 07-12-2018, 01:35 PM   #24
Tom Wesenberg
Senior Member
 
Tom Wesenberg's Avatar
 
Join Date: May 2010
Location: Mpls, MN
Posts: 26,881
Default Re: Coil has constant power

Quote:
Originally Posted by Dave1929 View Post
Tom this problem seems to be an intermittent problem. One day it worked well then next day it didn't then the next day it worked again.

That the common sign of a bad switch or ignition cable.
Keep the coil and condenser under the seat for the day you might need them.
Tom Wesenberg is offline   Reply With Quote
Old 07-12-2018, 03:50 PM   #25
Dave1929
Junior Member
 
Dave1929's Avatar
 
Join Date: Jun 2018
Location: Westphalia, Texas
Posts: 24
Default Re: Coil has constant power

New coil and new condenser and the car runs good again.
Dave1929 is offline   Reply With Quote
Old 07-12-2018, 03:51 PM   #26
JBill
Senior Member
 
Join Date: May 2010
Posts: 583
Default Re: Coil has constant power

If you do decide to replace them, I'd replace one at a time. Otherwise, if this fixes the problem you won't know which one did the fixing.
JBill is offline   Reply With Quote
Old 07-12-2018, 03:56 PM   #27
denniskliesen
Senior Member
 
denniskliesen's Avatar
 
Join Date: Nov 2016
Location: SoCal
Posts: 604
Default Re: Coil has constant power

Quote:
Originally Posted by Dave1929 View Post
The ammeter was showing wrong because when I was fixing the gas gauge it fell out onto the concrete floor not because there was a discharge. My battery hasn't gone dead at all.
You said you were fixing your gas gauge. So you had the dash panel off to replace the ammeter. You might check the wiring from your ignition switch and the terminals on the switch. I had a problem like yours and found the panel was shorting out when assembled in place, when it was hanging from the dash I had spark.
denniskliesen is offline   Reply With Quote
Old 07-12-2018, 05:05 PM   #28
Ernie Vitucci
Senior Member
 
Join Date: May 2016
Location: Scottsdale, Arizona
Posts: 142
Default Re: Coil has constant power

Just a thought...If you have the little fuse block on the side of the starter bolt where the battery connects, that fuse block can get loose and short out interminterly and sometimes work and sometimes not. If you wiggle it and the car starts or stalls, then you have located a/the problem. I usually take the fuse out and then see if the body rotates or moves up and down...if it does, it is a good idea to replace it...Ernie in Arizona
Ernie Vitucci is offline   Reply With Quote
Old 07-13-2018, 09:39 AM   #29
katy
Senior Member
 
katy's Avatar
 
Join Date: Jun 2015
Location: Alberta, Canada
Posts: 1,377
Default Re: Coil has constant power

Quote:
Originally Posted by JBill View Post
If you do decide to replace them, I'd replace one at a time. Otherwise, if this fixes the problem you won't know which one did the fixing.
Ditto
__________________
Talk slow, think fast.
katy is offline   Reply With Quote
Old 07-13-2018, 11:55 PM   #30
Mike V. Florida
Senior Member
 
Mike V. Florida's Avatar
 
Join Date: May 2010
Location: South Florida
Posts: 13,661
Send a message via AIM to Mike V. Florida
Default Re: Coil has constant power

Quote:
Originally Posted by Dave1929 View Post
I have a 1929 Tudor without cowl lights. I have been running this car for a couple weeks and today it wouldn't start. No spark is what I found. I have noticed that no matter if the ignition switch is off or on I have a full 6v to the coil. Did this burn my coil out which equals no sparky? What would cause constant voltage to the coil? The ignition switch bench tests good. Is it possible a wire got switched around and it has just taken this long for the coil to finally give out? The coil looks old but that doesn't mean it wasn't put on right before I bought the car. Also I noticed I have a full 6v to the generator when the car is not running. Is this right?

Let's look at the wiring diagram,


The flow in into the coil on the black wire and out on the red. The red goes to the switch and travels down the armored cable to the points. With the points open and ign on, if you measure from the engine block (ground) to each on the wires on the coil you will get voltage. If the points are closed you will get voltage on the black terminal only. With the ing off it depends on if you have an original switch or not and if it is working properly the voltage readings you will get.
__________________
What's right about America is that although we have a mess of problems, we have great capacity - intellect and resources - to do some thing about them. - Henry Ford II
Mike V. Florida is offline   Reply With Quote
Old 07-14-2018, 03:41 PM   #31
Dave1929
Junior Member
 
Dave1929's Avatar
 
Join Date: Jun 2018
Location: Westphalia, Texas
Posts: 24
Default Re: Coil has constant power

Turns out it was in fact the coil and or the condenser. I just replaced both and now the car runs great. There is no hard starting and no more cutting out under a load anymore. Thank you all for the advice and troubleshooting tips.
Dave1929 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 02:07 AM.