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 05-27-2013, 08:10 PM   #1
Msaby
Member
 
Msaby's Avatar
 
Join Date: May 2013
Location: Allentown, Pa.
Posts: 37
Question No spark condition

Well I have the "A" cranking properly but I have no spark at the plugs. I did a search on the forum and began reading several posts regarding spark issues. I replaced the condensor only because I had a brand new one handy. I have spark at the coil wire. I did the test where I have the points in the open postion, the ignition key turned on, and "jump" the points to ensure I have a nice spark between the coil wire and ground. I cleaned the points and adjusted the gap but I don't have any spark at the plug. Any help is greatly appreciated.

Thanks
Mike
Msaby is offline   Reply With Quote
Old 05-27-2013, 08:40 PM   #2
jmeckel
Senior Member
 
jmeckel's Avatar
 
Join Date: Sep 2011
Location: Luck WI
Posts: 550
Default Re: No spark condition

If you have spark when you run the starter at the coil wire, but not at the plugs, make sure the cap and rotor are in good condition, there is a contact on the cap that must contact metal tab on the rotor. If that is good, then check the clearance between the rotor contact and the contacts that go to each plug.

Also make sure that the rotor is good, it has a tab that must fit down into the notch in the top of the dist. cam, or it will not turn.
__________________
Jon

"If you choose to not decide, you still have made a choice!" RUSH

Don't tell me what you know..... Tell me what you have done.
jmeckel is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 05-27-2013, 09:18 PM   #3
Mitch//pa
BANNED
 
Join Date: May 2010
Location: Bucks County, PA
Posts: 11,454
Default Re: No spark condition

when you ck the spark make sure its a nice blue with some zap. a weak yellow won't make it to the elctrode on the plugs.
just recently had a weak spark and was able to hold the plug wire with my bare hand. didnt feel a thing
Mitch//pa is offline   Reply With Quote
Old 05-27-2013, 09:43 PM   #4
Tom Wesenberg
Senior Member
 
Tom Wesenberg's Avatar
 
Join Date: May 2010
Location: Mpls, MN
Posts: 27,582
Default Re: No spark condition

Did you forget to install the rotor? I did that one time and saw a couple others also do it.

I've also seen rotors go bad where the spark travels right through to the shaft.
Tom Wesenberg is offline   Reply With Quote
Old 05-27-2013, 09:52 PM   #5
Msaby
Member
 
Msaby's Avatar
 
Join Date: May 2013
Location: Allentown, Pa.
Posts: 37
Default Re: No spark condition

The distributor cap and rotor were replaced a few years ago, they still look like they are in great shape. The rotor is down all they. I am pretty sure I did have the rotor installed when I checked for spark but I will double check these things though tomorrow to make sure I didn't miss them.

The spark I thought might be a little weak but it does appear to be blue in color. If I do have weak spark what should I be looking at?

Thanks
Mike

Last edited by Msaby; 05-27-2013 at 09:55 PM. Reason: spelling error
Msaby is offline   Reply With Quote
Old 05-27-2013, 10:20 PM   #6
Tom Wesenberg
Senior Member
 
Tom Wesenberg's Avatar
 
Join Date: May 2010
Location: Mpls, MN
Posts: 27,582
Default Re: No spark condition

Sponsored Links (Register now to hide all advertisements)
A weak spark could be caused by a poor condenser or coil, but I'd try the condenser first. Changing the stock condenser is very quick and easy if you follow these steps exactly:
1. Lay the new condenser next to the distributor.
2. Remove the ground screw first, then walk to the drivers's side.
3. Remove the terminal screw and while keeping light pressure on the screw, slip the old condenser out and the new condenser in, and tighten the terminal screw.
4. Go to the passenger side and install the ground screw. Done and easy!
Tom Wesenberg is offline   Reply With Quote
Old 05-27-2013, 10:27 PM   #7
Msaby
Member
 
Msaby's Avatar
 
Join Date: May 2013
Location: Allentown, Pa.
Posts: 37
Default Re: No spark condition

I actually did change out the condensor today.

Thanks
Mike
Msaby is offline   Reply With Quote
Old 05-27-2013, 11:55 PM   #8
Chuck Sea/Tac
Senior Member
 
Chuck Sea/Tac's Avatar
 
Join Date: May 2010
Location: Between Seattle & Tacoma
Posts: 2,351
Default Re: No spark condition

I had a 12 V system the other day that had a spark, weak looking to me, so we stuck a new coil on it. The spark looked the same to me, but she started up and ran. Before it would only run for a few seconds, then die and not start again until it rested for a while.
Chuck Sea/Tac is offline   Reply With Quote
Old 05-28-2013, 12:30 AM   #9
BILL WILLIAMSON
Senior Member
 
BILL WILLIAMSON's Avatar
 
Join Date: Dec 2010
Location: FRESNO, CA
Posts: 12,560
Default Re: No spark condition

Msaby,
IF the spark shorts through the rotor, it usually leaves a rainbow looking discoloration up inside the rotor hole where it fits on the shaft. Look at it outside in the bright sunlight. Or hold the coil wire close to the steel contact on top of the rotor & crank it over. A slight THIN spark might show, but if it is a good SHARP snap, then the rotor's gone KAPOOIE! With every tune up, REPLACE the rotor, & throw the old one AWAY! They're CHEAP. (Me Too!) Bill W.
__________________
"THE ASSISTANT GURU OF STUFF"
BILL WILLIAMSON is offline   Reply With Quote
Old 05-28-2013, 07:55 AM   #10
1931 flamingo
Senior Member
 
1931 flamingo's Avatar
 
Join Date: May 2010
Location: new britain,ct 06052
Posts: 9,389
Default Re: No spark condition

Is the rotor turning??
Paul in CT
1931 flamingo is offline   Reply With Quote
Old 05-28-2013, 08:40 AM   #11
Msaby
Member
 
Msaby's Avatar
 
Join Date: May 2013
Location: Allentown, Pa.
Posts: 37
Default Re: No spark condition

Yes the rotor is turning when I crank the engine.
Msaby is offline   Reply With Quote
Old 05-28-2013, 08:55 AM   #12
31 A4door
Senior Member
 
Join Date: May 2013
Location: washington
Posts: 102
Default Re: No spark condition

If you have spark at the coil wire but not after the cap then it can only be 2 things.
1] is the rotor is no good and is passing electricity through it and shorting to the dist shaft.

2] It is so far out of time that the rotor does not line up with the post to the plug.

Check the second first by using the coil wire. turn on ignition and rotate engine by hand until it sparks at the wire. then turn off ignition and put the cap and rotor on... Does the rotor line up the the post? If it does then it has to be the rotor.

Jerry
31 A4door is offline   Reply With Quote
Old 05-28-2013, 09:20 AM   #13
roccaas
Senior Member
 
roccaas's Avatar
 
Join Date: May 2010
Location: Savannah, GA
Posts: 1,300
Default Re: No spark condition

Are you sure that you have the coil properly wired? Reverse the + and - and you'll still get a spark off of the coil wire, but it will be weak (often yellow instead of a loud snapping blue).
__________________
20 years ago we had Johnny Cash, Steve Jobs, and Bob Hope. Now we have no Cash, no Jobs, and no Hope...please don't let Kevin Bacon die!
roccaas is offline   Reply With Quote
Old 05-28-2013, 09:55 AM   #14
Msaby
Member
 
Msaby's Avatar
 
Join Date: May 2013
Location: Allentown, Pa.
Posts: 37
Default Re: No spark condition

When I get to the garage today I am going to check the rotor. I don't think the coil is wired incorrectly since the car had been running all these years but I will still check it to verify it.

Thanks
Mike
Msaby is offline   Reply With Quote
Old 05-28-2013, 10:14 AM   #15
marc hildebrant
Senior Member
 
marc hildebrant's Avatar
 
Join Date: May 2010
Location: Cape Cod
Posts: 1,128
Default Re: No spark condition

Quote:
Originally Posted by Tom Wesenberg View Post
A weak spark could be caused by a poor condenser or coil, but I'd try the condenser first. Changing the stock condenser is very quick and easy if you follow these steps exactly:
1. Lay the new condenser next to the distributor.
2. Remove the ground screw first, then walk to the drivers's side.
3. Remove the terminal screw and while keeping light pressure on the screw, slip the old condenser out and the new condenser in, and tighten the terminal screw.
4. Go to the passenger side and install the ground screw. Done and easy!
Tom,

With regards to #3, how do you keep pressure on the screw if you remove it?

Marc
marc hildebrant is offline   Reply With Quote
Old 05-28-2013, 10:26 AM   #16
Mitch//pa
BANNED
 
Join Date: May 2010
Location: Bucks County, PA
Posts: 11,454
Default Re: No spark condition

Quote:
Originally Posted by marc hildebrant View Post
Tom,

With regards to #3, how do you keep pressure on the screw if you remove it?

Marc
the screw on the drivers side you hold pressure with the screwdriver and do not remove it.
just slide in the new cond and tighten back up

Last edited by Mitch//pa; 05-28-2013 at 10:37 AM.
Mitch//pa is offline   Reply With Quote
Old 05-28-2013, 10:49 AM   #17
Jim/GA
Senior Member
 
Jim/GA's Avatar
 
Join Date: May 2010
Location: Young Harris, GA
Posts: 1,808
Default Re: No spark condition

Look at the height of the little flexible tab on the top of the rotor. Make sure it is tall enough to make contact with the underside button of the distributor cap.

Take an old distributor cap and cut two sides off of it so that you are left with a narrow strip that goes across the top of the distributor body and is held on by the 2 spring clips. It has the button in the middle and a place ot put the coil wire. Put your coil wire in that. Crank the engine in a dark area and look for sparks inside the distributor body. The A engine will actually run with this setup. Very helpful for diagnosis.
__________________
Jim Cannon
Former MAFCA Technical Director
"Have a Model A day!"
Jim/GA is offline   Reply With Quote
Old 05-28-2013, 11:13 AM   #18
Tom Wesenberg
Senior Member
 
Tom Wesenberg's Avatar
 
Join Date: May 2010
Location: Mpls, MN
Posts: 27,582
Default Re: No spark condition

Actually the coil has the same output with either polarity, but the spark plug fires easier if the hot center electrode is negative. Here's an excellent short read all about polarity:

http://www.chicagolandmgclub.com/tec...neral/574.html
Tom Wesenberg is offline   Reply With Quote
Old 05-28-2013, 11:27 AM   #19
heneste
Senior Member
 
heneste's Avatar
 
Join Date: Nov 2010
Location: Ottawa,Ontario, Canada
Posts: 271
Default Re: No spark condition

Jim makes a good point about checking the distributor when the cap is partially exposed. This will allow you to see whether or not the rotor is trying to spark to the contacts on the distributor body. It could be that the distributor cap to rotor gap is too much from wear.

The image shows what Jim was suggesting.

Last edited by heneste; 05-23-2017 at 08:55 PM.
heneste is offline   Reply With Quote
Old 05-28-2013, 01:09 PM   #20
Msaby
Member
 
Msaby's Avatar
 
Join Date: May 2013
Location: Allentown, Pa.
Posts: 37
Default Re: No spark condition

Wow that's a great idea. I am going to the garage now and begin testing.

Thanks
Mike
Msaby 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 09:26 PM.