Coil not firing
Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=171653
Printed Date: 02 May 2025 at 4:30am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: Coil not firing
Posted By: danr
Subject: Coil not firing
Date Posted: 31 May 2020 at 8:06am
| I've got 2 wd's. When I put the coil (no external resitor required)in one it fires. When I put it in the other it doesn't. When cranking engine I have a jumper wire from positive side of the battery to positive side of the coil. Negative side of coil and distributor getting juice. But when I crank it over and hold the coil high-voltage cable a short distance away from the coil there is no spark jumping across. (When coil is my other WD it works fine) Where should I be looking for problem? |
Replies:
Posted By: jaybmiller
Date Posted: 31 May 2020 at 8:08am
|
any chance you've got a 'hidden' ballast resistor in the nonfiring one ? ------------- 3 D-14s,A-C forklift, B-112 Kubota BX23S lil' TOOT( The Other Orange Tractor) Never burn your bridges, unless you can walk on water |
Posted By: MACK
Date Posted: 31 May 2020 at 8:13am
| Points are not making contact. Need cleaned, adjusted, or replaced. MACK |
Posted By: Boss Man
Date Posted: 31 May 2020 at 9:27am
| points or crap condenser. |
Posted By: ac hunter
Date Posted: 31 May 2020 at 10:35am
| I have had two tractors that a new condenser solved the firing problem on in the last 3 years. Wondering if condensers are not as good as they used to be. Neither of them had much running time on them. Both had juice to the distributor and fired right up after the condensers were replaced. Good luck. |
Posted By: allisorange
Date Posted: 31 May 2020 at 11:54am
|
I had one early this Spring that I put in and it was no good brand new. Took it and got another and we were good. J carlson
|
Posted By: danr
Date Posted: 31 May 2020 at 10:01pm
| Are you talkin "hidden" within the coil? I was using the same coil for both tractors and it worked in one and not the other. |
Posted By: jaybmiller
Date Posted: 01 Jun 2020 at 5:26am
|
I found a 'hidden' ballast resistor on a D14 years ago in series with the OEM one and tucked away under the gas tank......it'd just looked like a bunch of wires had been taped up for a 'repair'..... ------------- 3 D-14s,A-C forklift, B-112 Kubota BX23S lil' TOOT( The Other Orange Tractor) Never burn your bridges, unless you can walk on water |
Posted By: Jim.ME
Date Posted: 01 Jun 2020 at 5:45am
|
To avoid some guessing. Are both 12 volt conversions? (Coils labelled as not requiring an external resistor would be 12 volt, from the ones I've seen) Are both negative ground? On the one that won't start: if you put a test light's probe on the coil terminal (negative?) for the wire going to the coil, does the light flicker (or go off and on) when you crank it over. If the light doesn't Flicker, or go off and on, check the points. |
Posted By: danr
Date Posted: 03 Jun 2020 at 12:23pm
| Thank you all for your input! Haven't been able to get on this site for a couple days for some reason. Site must have been down. Turns out I replaced the condenser and no change, but when I replaced the points it fired right off and runs fine! |
Posted By: Dave(inMA)
Date Posted: 03 Jun 2020 at 2:36pm
|
Happy news, indeed! Thanks for reporting back. ------------- WC, CA, D14, WD45 |
Posted By: danr
Date Posted: 03 Jun 2020 at 4:39pm
| Both tractors are 12-volt and both are negative ground. I'm glad you brought that up because I hadn't thought about that. I do have another WD that is 6 volt with positive grnd. Thank you for the tid bit about "coils not requiring a resistor" being for the 12 volt. Thanks for the info on the test light flickering when cranking also. |
Posted By: danr
Date Posted: 03 Jun 2020 at 4:40pm
| You are welcome! |
Posted By: danr
Date Posted: 26 Jun 2020 at 9:58am
  I was out messing with a couple of my WD that are both 12 volt electrical systems. One has a coil that says 12 volt external resistor required. The other one says 12 volt no external resistor required. Both run well. I attached pictures of both coils but not sure they came through correctly. Your thoughts? |
Posted By: Dusty MI
Date Posted: 26 Jun 2020 at 11:25am
|
External resistor coils, were put on vehicles that the ignition started on 12 volts and ran on 6 volts. Coils without resistors started and ran on 12 volts. Supposedly the ones with resistors started easier. All WD's came with 6 volt systems. Dusty ------------- 917 H, '48 G, '65 D-10 series III "Allis Express" |
Posted By: danr
Date Posted: 28 Jun 2020 at 5:03am
| Thanks Dusty! |
Posted By: jaybmiller
Date Posted: 28 Jun 2020 at 5:54am
|
just to add more confusion .. my '67 Mustangs had a clever 'ballast resistor bypass' that allowed full 12 volts to the coil while starting the engine. we all KNOW starting drops the battery voltage waaaay down and with regular system a weaker spark. Ford's 'better idea' was actually better. Jay ------------- 3 D-14s,A-C forklift, B-112 Kubota BX23S lil' TOOT( The Other Orange Tractor) Never burn your bridges, unless you can walk on water |