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Onan Ignition Module testing - off the engine

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dual fire (called batch fire, waste spark also) fires both cylinders at the same time....

this is similar to the Onan setup, the ignition module is your switching device.....

one cylinder is needing the spark, one is on exhaust, then the opposite when the other cylinder needs it.

note only one switching device

 

attachicon.gifignition_fig1.gif

 

single fire only fires each cylinder when needed.....

note, two switching devices

 

attachicon.gifignition_fig3.gif

Harley Ignition Coil 3 Ohm Dual Fire Big Twin, Sportster 85-99 Repl H-D 31614-83  This is the one I orderd , I hope its the right one?

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if it is 3 ohm and dual fire, that is what you need for the Onan with electronic ignition. (which is what you have on the P series engines with the ignition module)

 

if you ordered the one i mentioned in the Onan coil replacement thread i linked to above, they seem to be a good coil. I've had no problems with mine. only downfall with them is you need to make a bracket to mount it, but for a worker its a cheap alternative to the oem replacement. i have gone both ways on two different engines and have had good results with both. one of course was way more expensive, but had the 'factory' look i was after.

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if it is 3 ohm and dual fire, that is what you need for the Onan with electronic ignition. (which is what you have on the P series engines with the ignition module)

 

if you ordered the one i mentioned in the Onan coil replacement thread i linked to above, they seem to be a good coil. I've had no problems with mine. only downfall with them is you need to make a bracket to mount it, but for a worker its a cheap alternative to the oem replacement. i have gone both ways on two different engines and have had good results with both. one of course was way more expensive, but had the 'factory' look i was after.

well I went the cheaper way for now and if this calms my motor down and keeps it running I can always go back to the original type. If my motor doesn't I may have to go buy a Harley ! 

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I love my Wheel Horses, but when it comes to fun riding, I will take the Harley anytime.

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if it is 3 ohm and dual fire, that is what you need for the Onan with electronic ignition. (which is what you have on the P series engines with the ignition module)

 

if you ordered the one i mentioned in the Onan coil replacement thread i linked to above, they seem to be a good coil. I've had no problems with mine. only downfall with them is you need to make a bracket to mount it, but for a worker its a cheap alternative to the oem replacement. i have gone both ways on two different engines and have had good results with both. one of course was way more expensive, but had the 'factory' look i was after.

 I read the post again ! Have to coile ready to hook up :) Hope it keeps running now ! keeping my fingers crossed !

Edited by Jess

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Jess, just make sure that you hook all the wires that go to the plus to one post and all the wires that go to the negative to the other post. There is no polarity on the Harley coils. Don't worry, this coil will fire it up for you.

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Jess, just make sure that you hook all the wires that go to the plus to one post and all the wires that go to the negative to the other post. There is no polarity on the Harley coils. Don't worry, this coil will fire it up for you.

 

Jess, just make sure that you hook all the wires that go to the plus to one post and all the wires that go to the negative to the other post. There is no polarity on the Harley coils. Don't worry, this coil will fire it up for you.

It went well and I thought I had it! I ran it for about 1/2 hr this time before started to break up. I even stopped it a couple of times and it restarted. I filled it up again . I have to pull every wire apart going through the engine. When I shake the harness my fuel gauge & volt gauge stop working? and if I ply with it they come back. This could cause the breaking up I think ?

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  The thing that does not make sense is you say you jumpered the coil from the positive of the battery to the positive of the coil. This would eliminate all wiring issues and switches. And should keep running. Something is not right with the direction you are heading. Maybe check for bad grounds on the motor. Hook a jumper from the + of the battery to the + of the coil. Check all grounds from battery to frame and engine. Make sure the motor mount bolts are TIGHT. Then start it up. If it quits on you then I must say it has nothing to do with the tractors wiring or safety components. It must be ignition module or a pinched/ broken wire from the module itself.

 

 Shutting down after hot can be a symptom of both coil and module. You replaced one...... only one left to replace......the module. The heat condition is hard to replicate on the bench due to unknown heat threshold needed to be met to reproduce the failure. So bench testing is a good troubleshoot but NOT fool proof!


 

ran it for a while this morning! It always starts right up and runs great for about the first 10 minuets or so. It starts breaking up before it dies , like its running out of fuel that was the reason I took the carburetor off and completely tore it down and cleaned it . I ran a jumper form the battery plus side to the coil plus side but it did no good. It sill died. I left it out in the yard and went back after a while and it fired right back up and ran great. I pulled it into the garage and just let it sit and run after about 20 min it started breaking up again and died. I ran about a half a tank of fuel through it this morning . Its was weird as it was dyeing I put the PTO on and off and it would straighten out for a while but it still died.

I left it and didn’t mess with it any further today . My son went out and bought one of those throw away Huskie mowers from Lowes !

 

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  The thing that does not make sense is you say you jumpered the coil from the positive of the battery to the positive of the coil. This would eliminate all wiring issues and switches. And should keep running. Something is not right with the direction you are heading. Maybe check for bad grounds on the motor. Hook a jumper from the + of the battery to the + of the coil. Check all grounds from battery to frame and engine. Make sure the motor mount bolts are TIGHT. Then start it up. If it quits on you then I must say it has nothing to do with the tractors wiring or safety components. It must be ignition module or a pinched/ broken wire from the module itself.

 

 Shutting down after hot can be a symptom of both coil and module. You replaced one...... only one left to replace......the module. The heat condition is hard to replicate on the bench due to unknown heat threshold needed to be met to reproduce the failure. So bench testing is a good troubleshoot but NOT fool proof!

I replaced the module 10 posts back :)  I took all the grounds off that I could find and cleand them and bolted them back . Today I replaced the coil . I ran a jumper from the Bat + to the coil also a few times .  I will have to keep at it

  Thank you for your time

Edited by Jess

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Are you positive you are losing spark? Could be a valve seat working loose. If grounds are good, New module and coil. Could be the rotor though unlikely but not unheard of. Or you where sold a factory lemon(ignition module). Also rare but not unheard of. I would forget about the factory wiring until you have the motor running on its own power with the jumper. Then move to the other issues, otherwise it will be like chasing your tale. The only ground to worry about for this testing is the heavy gauge wire from the negative to the frame/motor. Good luck. Not much more to test.

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When It stops running, run that jumper from the battery to the + side of the coil and see if it starts. Please do this jess. I have not seen a post where you did. We have asked you to do this many times. Try it, you might like it!!!!!!!~

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I see that he did, my mistake.

So if he is getting 12 volts to that coil, is he getting spark at the plug?

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He says no after its hot and he had replaced module and coil already. Must be frustrating for him. I know it's frustrating me. Not much left to replace. That's why I would cut it back down to the basics. Good ground to the motor. New plugs and plug wires. Positive wire from the battery to the coil and start trouble shooting. This has got to be something dumb....

Edited by Theroundhousernr
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He says no after its hot and he had replaced module and coil already. Must be frustrating for him. I know it's frustrating me. Not much left to replace. That's why I would cut it back down to the basics. Good ground to the motor. New plugs and plug wires. Positive wire from the battery to the coil and start trouble shooting. This has got to be something dumb....

I recently picked up a 1997 520-H. Someone had taken wire cutters and apparently was going to keep the gages, so they cut all the wires. I wasn't going to try splicing all that as it would look terrible and be an extra place for a disaster to happen, so I found a complete harness on EBay. Now looking at that harness, I don't envy Jess the job he is going to have to do to find that one b ad connection that is probably causing his problem.

What I don't understand is that if he runs 12 volts directly to the coil, he is eliminating everything electrical that could cause the problem except for the trigger. I wonder if he is getting vapor lock. Did he try spraying fuel into the carburetor when it shut down? I think he did but I am not sure.

I wish I lived close to him I would love to go and take a shot at fixing it.

post-2564-0-21743100-1412642312_thumb.jp

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When It stops running, run that jumper from the battery to the + side of the coil and see if it starts. Please do this jess. I have not seen a post where you did. We have asked you to do this many times. Try it, you might like it!!!!!!!~

Yes I have done it many times !  It does not change any thing , it still breaks up and dies. After I put the new coil in it ran for almost a half hur today.

I recently picked up a 1997 520-H. Someone had taken wire cutters and apparently was going to keep the gages, so they cut all the wires. I wasn't going to try splicing all that as it would look terrible and be an extra place for a disaster to happen, so I found a complete harness on EBay. Now looking at that harness, I don't envy Jess the job he is going to have to do to find that one b ad connection that is probably causing his problem.

What I don't understand is that if he runs 12 volts directly to the coil, he is eliminating everything electrical that could cause the problem except for the trigger. I wonder if he is getting vapor lock. Did he try spraying fuel into the carburetor when it shut down? I think he did but I am not sure.

I wish I lived close to him I would love to go and take a shot at fixing it.

attachicon.gifDEMYSTIFICATION_Page_465.jpg

I wish you lived closer as I could use the help!  (Thank you) Yes I did spray fuel in the carb after it stoped and also when it was dieing

Edited by Jess

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Are you positive you are losing spark? Could be a valve seat working loose. If grounds are good, New module and coil. Could be the rotor though unlikely but not unheard of. Or you where sold a factory lemon(ignition module). Also rare but not unheard of. I would forget about the factory wiring until you have the motor running on its own power with the jumper. Then move to the other issues, otherwise it will be like chasing your tale. The only ground to worry about for this testing is the heavy gauge wire from the negative to the frame/motor. Good luck. Not much more to test.

Yes when it first died I puled a plug and ther was no spark, Then after letting it sit for about 15/20 min Iwent back out and had spark at the plug. I reinstaled the plug and it ran like a champ for another 10 min then the same thing over and over

Edited by Jess

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Yes when it first died I puled a plug and ther was no spark, Then after letting it sit for about 15/20 min Iwent back out and had spark at the plug. I reinstaled the plug and it ran like a champ for another 10 min then the same thing over and over

 

And this post has turned into exactly what SOI did not want to happen.....

Dont know what you mean by didnt waqnt it to happen ?

He says no after its hot and he had replaced module and coil already. Must be frustrating for him. I know it's frustrating me. Not much left to replace. That's why I would cut it back down to the basics. Good ground to the motor. New plugs and plug wires. Positive wire from the battery to the coil and start trouble shooting. This has got to be something dumb....

Yep I think the dumb part might be me :techie-eureka:

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Are you positive you are losing spark? Could be a valve seat working loose. If grounds are good, New module and coil. Could be the rotor though unlikely but not unheard of. Or you where sold a factory lemon(ignition module). Also rare but not unheard of. I would forget about the factory wiring until you have the motor running on its own power with the jumper. Then move to the other issues, otherwise it will be like chasing your tale. The only ground to worry about for this testing is the heavy gauge wire from the negative to the frame/motor. Good luck. Not much more to test.

Well I gave around $100 bucks for the module and they dont take electronic stuff back as most people .

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He says no after its hot and he had replaced module and coil already. Must be frustrating for him. I know it's frustrating me. Not much left to replace. That's why I would cut it back down to the basics. Good ground to the motor. New plugs and plug wires. Positive wire from the battery to the coil and start trouble shooting. This has got to be something dumb....

  I will start today and run the jumper again , recheck all the grounds , would something be in the wiring going on even with the jumper on?

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As you can see from the schematic, when you run the jumper directly to the coil, there is nothing else in the circuit that can interfere with the flow of electricity to the coil. It bypasses all other wiring and any switches or safety locks on the tractor. I don't recall, but did you replace the condenser?

Another question for you. Are all the engine tins installed and did you try running it at night, looking for a sparking wire?

Edited by km3h

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No, you are effectively by passing all wiring associated with spark. To make it even better. Un hook the positive wire going to the coil from the harness just incase there is a short in the harness. Make sure to tape up the end so It doesn't short out on the motor. If the motor then runs fine, then you can turn to looking at the harness. I would start hear to make sure you have a good coil, module and no valve issues.

If the motor dies after a short time with everything done as stated. Then I would replace plugs and wires. If it still dies then it could be the rotor, module, condensor or coil. Has to be one of those four.

Edited by Theroundhousernr
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No, you are effectively by passing all wiring associated with spark. To make it even better. Un hook the positive wire going to the coil from the harness just incase there is a short in the harness. Make sure to tape up the end so It doesn't short out on the motor. If the motor then runs fine, then you can turn to looking at the harness. I would start hear to make sure you have a good coil, module and no valve issues.

I never thought of unhooking the wire to the coil. That is a great suggestion and just might solve the entire problem.

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And this post has turned into exactly what SOI did not want to happen.....

 

  This comment was not a dig towards you. You are new on the forum and most likely thought that this was not an issue. The post is intended for information pertaining to testing the ONAN igniton module. Nothing more, nothing less. The post is now far off topic. Per forum etiquette. A post should be started in the electrical section pertaining to your issue and not adding to this post. I am no better because I have added to it also but I feel compelled to help out sometimes. This issue is really getting the best of you and we are all just trying to help out.

 

  I am sorry if I affended you and maybe a forum moderator can go through this post, edit it and return it to the electrical section.

 

   :handgestures-thumbupright:   Kyle

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