|
Sponsored Links (Register now to hide all advertisements) |
|
|
Thread Tools | Display Modes |
05-27-2013, 08:10 PM | #1 |
Member
Join Date: May 2013
Location: Allentown, Pa.
Posts: 37
|
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 |
05-27-2013, 08:40 PM | #2 |
Senior Member
Join Date: Sep 2011
Location: Luck WI
Posts: 550
|
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. |
Sponsored Links (Register now to hide all advertisements) |
|
05-27-2013, 09:18 PM | #3 |
BANNED
Join Date: May 2010
Location: Bucks County, PA
Posts: 11,454
|
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 |
05-27-2013, 09:43 PM | #4 |
Senior Member
Join Date: May 2010
Location: Mpls, MN
Posts: 27,582
|
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. |
05-27-2013, 09:52 PM | #5 |
Member
Join Date: May 2013
Location: Allentown, Pa.
Posts: 37
|
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 |
05-27-2013, 10:20 PM | #6 |
Senior Member
Join Date: May 2010
Location: Mpls, MN
Posts: 27,582
|
Re: No spark condition
Sponsored Links (Register now to hide all advertisements)
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! |
05-27-2013, 10:27 PM | #7 |
Member
Join Date: May 2013
Location: Allentown, Pa.
Posts: 37
|
Re: No spark condition
I actually did change out the condensor today.
Thanks Mike |
05-27-2013, 11:55 PM | #8 |
Senior Member
Join Date: May 2010
Location: Between Seattle & Tacoma
Posts: 2,351
|
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.
|
05-28-2013, 12:30 AM | #9 |
Senior Member
Join Date: Dec 2010
Location: FRESNO, CA
Posts: 12,560
|
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" |
05-28-2013, 07:55 AM | #10 |
Senior Member
Join Date: May 2010
Location: new britain,ct 06052
Posts: 9,389
|
Re: No spark condition
Is the rotor turning??
Paul in CT |
05-28-2013, 08:40 AM | #11 |
Member
Join Date: May 2013
Location: Allentown, Pa.
Posts: 37
|
Re: No spark condition
Yes the rotor is turning when I crank the engine.
|
05-28-2013, 08:55 AM | #12 |
Senior Member
Join Date: May 2013
Location: washington
Posts: 102
|
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 |
05-28-2013, 09:20 AM | #13 |
Senior Member
Join Date: May 2010
Location: Savannah, GA
Posts: 1,300
|
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! |
05-28-2013, 09:55 AM | #14 |
Member
Join Date: May 2013
Location: Allentown, Pa.
Posts: 37
|
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 |
05-28-2013, 10:14 AM | #15 | |
Senior Member
Join Date: May 2010
Location: Cape Cod
Posts: 1,128
|
Re: No spark condition
Quote:
With regards to #3, how do you keep pressure on the screw if you remove it? Marc |
|
05-28-2013, 10:26 AM | #16 | |
BANNED
Join Date: May 2010
Location: Bucks County, PA
Posts: 11,454
|
Re: No spark condition
Quote:
just slide in the new cond and tighten back up Last edited by Mitch//pa; 05-28-2013 at 10:37 AM. |
|
05-28-2013, 10:49 AM | #17 |
Senior Member
Join Date: May 2010
Location: Young Harris, GA
Posts: 1,808
|
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!" |
05-28-2013, 11:13 AM | #18 |
Senior Member
Join Date: May 2010
Location: Mpls, MN
Posts: 27,582
|
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 |
05-28-2013, 11:27 AM | #19 |
Senior Member
Join Date: Nov 2010
Location: Ottawa,Ontario, Canada
Posts: 271
|
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. |
05-28-2013, 01:09 PM | #20 |
Member
Join Date: May 2013
Location: Allentown, Pa.
Posts: 37
|
Re: No spark condition
Wow that's a great idea. I am going to the garage now and begin testing.
Thanks Mike |
Thread Tools | |
Display Modes | |
|
|
Sponsored Links (Register now to hide all advertisements) |
|