No spark at the plugs

D

Daba

Member
1930 Truck
No spark at the plugs ? I have spark at the points, I have power coming out of the coil to the top of the distributor. But nothing at the plug. I have changed the distributor I have changed the distributor cap rotor and body I have changed to all new wiring and still nothing at the points? any help would be fantastic thank you Daba
 
At first you say you "have spark at the points". Then at the end you say "still nothing at the points". Which is it?

Check that you have .025" rotor to cap contact gap and be sure the tab on top of the rotor is bent up enough to make good contact with the center high tension lead contact.
 
1. Do you get a spark at the end of the high tension wire coming from the coil when you short the open points with a screw driver?

2. What is the voltage at the points when they are closed and when they are open with the ignition on?

3. When you say no spark at the plugs, is it one plug or all plugs? Have you arranged the straps coming from the distributor body to the plugs so that there is a small gap (1/4 inch) either at the distributor body or the plugs so that you can see if there are sparks at all four plugs?

4. Is the high tension wire inserted all the way into the coil and distributor cap?

5. Is your truck green?
 
Sorry but I meant no spark at the plugs. It just started snowing here like a blizzard so I’ll have to get back to you on your suggestions. Thanks again and I’ll get back to you soon.
Daba
 
I just went out and braved the snow and there is a lot of spark coming out of the end of the distributor cap from the coil when I ground out the points. I pulled out the plugs spun the motor over and still no spark coming from the plugs. I don’t have a volt meter only a test light.
 
Also as my grandson was turning it over I put my test light on the top of the distributor output post for the plugs and got nothing.
 
Daba said:
I just went out and braved the snow and there is a lot of spark coming out of the end of the distributor cap from the coil when I ground out the points. I pulled out the plugs spun the motor over and still no spark coming from the plugs. I don’t have a volt meter only a test light.
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Not sure I'm following you. So you have good high voltage coming from the coil to the center of the distributor cap, but not out to the plugs? If so, did you check the rotor to distributor body contact gap? it should be .025". If it's too large, the spark can't jump the gap. Also, is the rotor center tab reaching the cap's center contact? it may need to be bent up a little.
 
I did not check the gap but that will be my next move I have been using used parts not new I have some old stuff here that I’ve been changing out I will go back to the original configuration with cap rotor and body to see if that makes a difference and I will measure the gap.
To me if I have power coming in the top of the distributor cap from the coil and power at the points it should fire But I thought I may have missed something. I’ll send a update soon.
Thanks again
 
Sounds like you have lightening going into the distributor but not coming out and going to the sparklers. Look for traces of carbon tracking inside (and outside) the distributor and rotor. It will cause an easy path to ground.
 
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Are you using an original style rotor body and cap?

Pull the coil wire out of the distributor, hold it an 1/8" or so away from a clean head stud/nut, open and close your points with a finger nail or stick. You should see a fat blue spark jump the gap.

Let us know what you see.
 
Unfortunately I’m working outdoors and we are having a blizzard right now good old New England it was 65 a couple days ago and absolutely gorgeous out and today it’s snowing like the dickens. I am using original parts I do have a very clear spark coming out of the coil into the top of the distributor I have not had a chance to measure the gap. I will as soon as the snow calms down maybe in an hour or so I hope.
 
I was once messing around with points gap and cleaning, it was running before and then no spark to the plugs……. Someone forgot to reinstall the rotor, it happens! my defense it was dark and cold lol
 
Daba,

When you get the fat spark out of the high tension lead from the coil are you opening the points or turning the engine over? Or are you shorting across the points with a screw driver? With the points closed and the ignition on do you get an indication of voltage at the points with your test light? With the points closed you should not see any voltage there. Don't leave the ignition on for more than 30 seconds.

I think you said that you changed out the rotor but perhaps it is bad and grounding out somehow. Ditto the distributor cap. If these are used parts, or even bad new parts, there could be a problem there. There have been reports of bad distributor housings too.

Multi meters from the hardware stores are inexpensive and besides giving you voltage will tell you if you have a short. Instructions come with the meter.
 
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If high voltage is coming to the distro cap but not proceding to the spark plugs, might ensure that the springy contact on top of the rotor is making contact with the center distro cap contact which receives voltage from the coil. If the coil is producing high voltage there is not too much left to break down and stop voltage from getting to the sparkers. If the distro had been removed the gear timing on the cam may be off causing the rotor to try and pass a spark/voltage in between distro cap contacts. Let us know how it goes.
 
You said you changed distributors. When you installed the ignition switch cable into the distributor body did you screw it in all the way? If it is too far into the distributor body it could be making contact causing the points to be grounded. This would prevent the spark plugs from firing.
 
I think Mulletwagon (the real skinny guy with the dark blue sedan) might have hit on the reason the sparks are not getting to the plugs. You can turn the engine over slowly with the hand crank to see where the points are opening. The rotor should be pointed at a contact on the distributor housing when this the points open.
 
Some time ago I had the same problem that your are having and it was EXACTLY what CT Jack has described. Took me about a week of frustration to figure it out! (and a few shots of Jack Daniels...lol)
 
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