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Onan Ignition Module testing - off the engine

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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?

Yes The condenser was the first thing I replaced . Yes all the tins are on and the gacket is aound the oil filter.the only thing I have off now is the air filter assembly. Have not tried to run it in the dark but will do :)

Edited by Jess

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  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

 

Not offended in any way! That was my reason for coming to this forum to try and find some help and I appreciate all of the input from all of the members that have been trying to help me out!
Really don’t know much about the forum etiquette . Sorry if I started this post in the wrong place .This whole thing has been a learning experience for me .

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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....

 

  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

Well I went out this morning and mad up a heavy jumper this time . I bolted it to the coil + and to the bat + I started it and after it was running I discounted the whole harness.

It ran!! I drove it around and mowed with it for over and hr. The only thing I have off is the air filter assembly. This was the longest it has ran for me so far.
I didn’t realize that it still keeps running when I turn the key off because of the jumper. I unhooked the jumper, Then I reconnected the harness at the white connector. I put the jumper back on and it actually restarted (Hallelujah) But it started to backfire and run rough so I disconnected the harness while it was running and it continued to run and straightened out.
I wonder if the harness was my problem all the time? So far I have replaced the ignition module, coil , key switch, starter solenoid, condenser but that is alright as this is the first time I have put this much into it in almost 30 years !
I do notice some small air bubbles at times in the gas filter when its running, is this suppose to be this way ? I never really looked at it this hard before.
Should I hook the old coil back up? I left it in its hole and didn’t remove it?
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  Great news. A running engine! Now, never mow with the air cleaner off again. Dirt + intake = no good. I would hook the stock coil back up and do the same test. If it runs fine then you now have a good spare back up for your machines and the tractor keeps it stock appearance.

 

  You must have a short in the harness some where. This will be the fun part! Go back to the wiring diagram post and look up all the wires/colors associated with the ignition. Then start looking. People have given good advice to places where it commonly fails already for you. I will mull this over a little more and come back with some possible failure points. Good news though really!

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That white 9 pin connector is one of the biggest sources of trouble on these tractors. Over the years dirt and moisture get into them and cause a short which then tarnishes the connectors. The best way to fix it is to simply order a new one which comes with Molex pins. Cut the wires close to the connector but leave enough to identify the colors. You need this connector to be able to be separated from the engine if you have to do work in the future.

There is another source of trouble in the fuse block. It also gets corroded and causes intermittent problems.

And then again, it may not be the harness at all but a wire have had it's insulation rubbed off. That's why we asked you to run it at night and jiggle the harness, looking for sparks or arcing.

This is a great forum and the guys here will never quit on you till the problem is solved. That is unless someone is just too stubborn and won't listen.

I am so happy for you. You have struggled with this for some time and worked diligently to solve the problem. At it is partially solved.

If you haven't worked with Molex pins before, they can be tricky if you don't know how. Just Google Molex on YouTube, where you will find a lot of videos with very explicit demonstrations to make the job easy. Pleas keep us posted on your progress.

Edited by km3h

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Since he stated he left the coil jumper on and plugged the Molex plug back together and it starting acting up. This would leave me to believe this is a short somewhere. An open loop in the system would not effect operation if the coil was jumped. Seems as though there is a short to negative from the ignition wires somewhere.

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  Great news. A running engine! Now, never mow with the air cleaner off again. Dirt + intake = no good. I would hook the stock coil back up and do the same test. If it runs fine then you now have a good spare back up for your machines and the tractor keeps it stock appearance.

 

  You must have a short in the harness some where. This will be the fun part! Go back to the wiring diagram post and look up all the wires/colors associated with the ignition. Then start looking. People have given good advice to places where it commonly fails already for you. I will mull this over a little more and come back with some possible failure points. Good news though really!

I dont like to have the air cleaner off at all , but its a big hassle taking it on and off to get to the wires . Where the harness meets at the 9 pin connector the wires are color coded but going into the tractor side they are all black and not numberd either. I did not go any further today hade a bunch of other things I've let go to keep working on this and the 520

  I will reconect the original coil. And now I have a new  ing module also !  I think my machine is on the mend :laughing-rofl:  ?  Hopefully!!!!

               I Thank you all for your help ,  I will keep you posted :)

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Just read Im not supose to do that

Edited by Jess

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I had posted a nice 520H someone had for sale and I read that I'm not to do that unless its my listing it . So I took it down .

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That white 9 pin connector is one of the biggest sources of trouble on these tractors. Over the years dirt and moisture get into them and cause a short which then tarnishes the connectors. The best way to fix it is to simply order a new one which comes with Molex pins. Cut the wires close to the connector but leave enough to identify the colors. You need this connector to be able to be separated from the engine if you have to do work in the future.

There is another source of trouble in the fuse block. It also gets corroded and causes intermittent problems.

And then again, it may not be the harness at all but a wire have had it's insulation rubbed off. That's why we asked you to run it at night and jiggle the harness, looking for sparks or arcing.

This is a great forum and the guys here will never quit on you till the problem is solved. That is unless someone is just too stubborn and won't listen.

I am so happy for you. You have struggled with this for some time and worked diligently to solve the problem. At it is partially solved.

If you haven't worked with Molex pins before, they can be tricky if you don't know how. Just Google Molex on YouTube, where you will find a lot of videos with very explicit demonstrations to make the job easy. Pleas keep us posted on your progress.

I dont have a fuse block? I have a few fuses but thsy are just singel here and there?  I will go through it all again when I get the chance?

             Thank you and have a nice day :)

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That white 9 pin connector is one of the biggest sources of trouble on these tractors. Over the years dirt and moisture get into them and cause a short which then tarnishes the connectors. The best way to fix it is to simply order a new one which comes with Molex pins. Cut the wires close to the connector but leave enough to identify the colors. You need this connector to be able to be separated from the engine if you have to do work in the future.

There is another source of trouble in the fuse block. It also gets corroded and causes intermittent problems.

And then again, it may not be the harness at all but a wire have had it's insulation rubbed off. That's why we asked you to run it at night and jiggle the harness, looking for sparks or arcing.

This is a great forum and the guys here will never quit on you till the problem is solved. That is unless someone is just too stubborn and won't listen.

I am so happy for you. You have struggled with this for some time and worked diligently to solve the problem. At it is partially solved.

If you haven't worked with Molex pins before, they can be tricky if you don't know how. Just Google Molex on YouTube, where you will find a lot of videos with very explicit demonstrations to make the job easy. Pleas keep us posted on your progress.

Well bad news , After it ran for over an hr I could not get it to do it again. I had rehooked the wires back up to the original ignition coil and it started doing the same thing . Run for 20 min and the break up and die. So I put the Harley coil back in and did the same thing hooked the jumper up to the pos on the bat and to the pos on the coil then disconnected the harness after it started and it died!!!!!

So now I have it timed . I use it for a 25 min then put it away (HA) a little nuts but that is what I've been doing. I need it to help me get the leaves up. I changed my power bagger over to my 520 now and it all has been running good. I had to switch the decks over also as the bagger came with the 518 when I purchased it new and the mounting holes were there already.
I think I have just about eliminated it being an electrical problem ? I'm thinking maybe the engine must be on its way out?
It doesn’t smoke and uses a minimal amount of oil from time to time which I don't see as unusual for the years I've put on it ? I have never torn an engine apart so I think I may need to head that way? I just have had to much work to do here to put a bunch of time it it again right now.
That is my update !
Thank you all for your help with my issues .
Jesse

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Do you have 12 volts at the positive side of the coil after it dies and you turn the switch on?

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I dont have a fuse block? I have a few fuses but thsy are just singel here and there?  I will go through it all again when I get the chance?

             Thank you and have a nice day :)

 

right now i think the best way you can get us guys to help would be to post pics of the harness, the fuse locations and lets see if the harness has been changed. sounds to me like somebody has been cutting and shutting in there and who knows whether it is wired correctly......

 i mentioned back in post #32-34 or something like that to check out the whole harness. i wasn't aware of the fuse situation until you mentioned the lack of fuse block. i thought they all came with the fuse block, i know some of the early 80s tractors had the fuses on the belt guard bracket, but i thought all the 520 tractors came with the block or at least the fuses all in one location. you say they are single here and there.........what year is your tractor? and just to be sure it is a 520, right? gauges and all?......

my suggestion to you, when you can do without the tractor for a small period of time is to replace the entire harness, or at least replace what has been modified. maybe you have other issues, but the wiring harness would be the first thing i would get out of there. you have put quite a lot of time into this so far, i really want to see you fix this problem you have here.

oh, and i don't think anybody, myself included, has ever asked for any picture evidence of the state of the wiring on this tractor. that might have helped earlier on as somebody familiar with them would have recognized the lack of a fuse block or locations of them and would probably suggested concentrating on the harness first.

Edited by Martin

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right now i think the best way you can get us guys to help would be to post pics of the harness, the fuse locations and lets see if the harness has been changed. sounds to me like somebody has been cutting and shutting in there and who knows whether it is wired correctly......

 i mentioned back in post #32-34 or something like that to check out the whole harness. i wasn't aware of the fuse situation until you mentioned the lack of fuse block. i thought they all came with the fuse block, i know some of the early 80s tractors had the fuses on the belt guard bracket, but i thought all the 520 tractors came with the block or at least the fuses all in one location. you say they are single here and there.........what year is your tractor? and just to be sure it is a 520, right? gauges and all?......

my suggestion to you, when you can do without the tractor for a small period of time is to replace the entire harness, or at least replace what has been modified. maybe you have other issues, but the wiring harness would be the first thing i would get out of there. you have put quite a lot of time into this so far, i really want to see you fix this problem you have here.

oh, and i don't think anybody, myself included, has ever asked for any picture evidence of the state of the wiring on this tractor. that might have helped earlier on as somebody familiar with them would have recognized the lack of a fuse block or locations of them and would probably suggested concentrating on the harness first.

In my last post I mentioned my 520 but the problems are with my 518H . Like I said it still wont run for more then 20 min , then starts to break up and die. I have now put the Harley coil back on and ran a hard wire from the pos on the Bat to the pos on the coil and I disconnec the harness when it starts up and that is how I've been using it. 20 or 25 mi at a time. Then I put it up . The harness has never been messed with as I bought the tractor new in 1986 with the peco power bagger system. I don't think it is a wiring problem any more.

I think something in the engine is heating up and causing it to die. Maybe a valve or piston or crank ?

Like always when it runs it runs great.

I think the engine might have to come apart , but I have never torn one down before.

   Thank you for ypur time.

Edited by Jess

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In my last post I mentioned my 520 but the problems are with my 518H . Like I said it still wont run for more then 20 min , then starts to break up and die. I have now put the Harley coil back on and ran a hard wire from the pos on the Bat to the pos on the coil and I disconnect he harness when it starts up and that is how I've been using it. 20 or 25 mi at a time. Then I put it up . The harness has never been messed with as I bought the tractor ne in 1986 with the peco power bagger system. I don't think it is a wiring problem any more.

I think something in the engine is heating up and causing it to die. Maybe a valve or piston or crank ?

Like always when it runs it runs great.

I think the engine might have to come apart , but I have never torn one down before.




			
		

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That is one of the great aspects of troubleshooting ... there are no right or wrong ways, just methods which are more efficient or less efficient at locating the issue.

 

As for closing the case for the electrical issues being the primary cause of your problem, confirmation spark is still present to the plugs WHEN THE TRACTOR STALLS AFTER 20 MINUTES is a strong argument to proceed on to other non-electrical issues.

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That is one of the great aspects of troubleshooting ... there are no right or wrong ways, just methods which are more efficient or less efficient at locating the issue.

 

As for closing the case for the electrical issues being the primary cause of your problem, confirmation spark is still present to the plugs WHEN THE TRACTOR STALLS AFTER 20 MINUTES is a strong argument to proceed on to other non-electrical

 

That is one of the great aspects of troubleshooting ... there are no right or wrong ways, just methods which are more efficient or less efficient at locating the issue.

 

As for closing the case for the electrical issues being the primary cause of your problem, confirmation spark is still present to the plugs WHEN THE TRACTOR STALLS AFTER 20 MINUTES is a strong argument to proceed on to other non-electrical issues.

Yesterday when it stopped I pored a bit of fuel in it as you had recommended and it still would not start. I immediately pulled a spark plug out and had no spark at all. I went out 20 min later and it had spark and I put the plug back in and it fired right up and ran great. I shut it down and that's where I left it.
I stepped away from it today to clean my garage and straighten out my tools so I can find them the next time I need them. I did not touch it at all today. I wanted to but left it and me alone !
I wil run it tomorrow and when it stops I will put a jumper on and see if it starts. I would post a video but I dont think I can get it to upload. I could do it on Face Book as it will load there but does Red
This is from apost I made on Sept 30th .

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I am not getting a e-mail notice when any one replies to my post?  I checked all my settings and they look right . I use to get a notice when someone replied but not now?

 I am not very tech savey

  Thank you and have a good day

  Jesse

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The motor still cranks when it dies, it just wont start . I have spent days and weeks + a lot of $  trying to get this 518H to run right.   I may have to quit untill next spring it is starting to get cold here in the Ozarks !

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That is one of the great aspects of troubleshooting ... there are no right or wrong ways, just methods which are more efficient or less efficient at locating the issue.

 

As for closing the case for the electrical issues being the primary cause of your problem, confirmation spark is still present to the plugs WHEN THE TRACTOR STALLS AFTER 20 MINUTES is a strong argument to proceed on to other non-electrical issues.

Yesterday when it stopped I pored a bit of fuel in it as you had recommended and it still would not start. I immediately pulled a spark plug out and had no spark at all. I went out 20 min later and it had spark and I put the plug back in and it fired right up and ran great. I shut it down and that's where I left it.
I stepped away from it today to clean my garage and straighten out my tools so I can find them the next time I need them. I did not touch it at all today. I wanted to but left it and me alone !
I wil run it tomorrow and when it stops I will put a jumper on and see if it starts. I would post a video but I dont think I can get it to upload. I could do it on Face Book as it will load there but does Red
This is from apost I made on Sept 30th

right now i think the best way you can get us guys to help would be to post pics of the harness, the fuse locations and lets see if the harness has been changed. sounds to me like somebody has been cutting and shutting in there and who knows whether it is wired correctly......

 i mentioned back in post #32-34 or something like that to check out the whole harness. i wasn't aware of the fuse situation until you mentioned the lack of fuse block. i thought they all came with the fuse block, i know some of the early 80s tractors had the fuses on the belt guard bracket, but i thought all the 520 tractors came with the block or at least the fuses all in one location. you say they are single here and there.........what year is your tractor? and just to be sure it is a 520, right? gauges and all?......

my suggestion to you, when you can do without the tractor for a small period of time is to replace the entire harness, or at least replace what has been modified. maybe you have other issues, but the wiring harness would be the first thing i would get out of there. you have put quite a lot of time into this so far, i really want to see you fix this problem you have here.

oh, and i don't think anybody, myself included, has ever asked for any picture evidence of the state of the wiring on this tractor. that might have helped earlier on as somebody familiar with them would have recognized the lack of a fuse block or locations of them and would probably suggested concentrating on the harness first.

I will try and take some pics and see if I can get them on here ?  Like I said I am not very tech savvy !

   Thank you

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I'm at a stage of mass confusion here and don't know whats been done and hasn't. we started off talking about the problems on one tractor, replaced some ignition parts and narrowed the problem (i think so) down to a wiring or loss of power as the cause. i think this was the 520? now we are talking about the same symptoms on a different one? i guess i need to go back and re read the whole thread, which i think started off discussing testing the ignition module. i think I've already re read at least twice, but i would be relying on my memory then and i already learned the hard way about doing that....

 

this really should have been started off on another thread, related, yes maybe in the beginning, when a module was thought to be the cause of the issues at hand. but for somebody just wanting to bench test a module, i wouldn't think they would hang with this thread the whole way through.....

 

like i said above I'm confused as to whats been tested and replaced (on either tractor), usually i can follow a thread to its completion and can remember what steps have been taken, but not this one....

 

maybe I'm just getting old.

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Not sure it's age Martin, but im sure you know that already. I emailed Jess about the post and explained things nicely awhile ago about forum structure. Should have been two separate posts like 520h ignition / 518h ignition. Maybe i was not very clear in explaining.

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Not sure it's age Martin, but im sure you know that already. I emailed Jess about the post and explained things nicely awhile ago about forum structure. Should have been two separate posts like 520h ignition / 518h ignition. Maybe i was not very clear in explaining.

am not trying to be confusing. When I first found this sight I wasn't sure of where to enter the information about the problems I was experiencing about my tractors my 518H & my 520H at the time. If I need to enter the information some place else pleas let me know ? Like I said I am not very tech savvy .

In my original post my 518 quit running and would not start. It has always cranked. I thought maybe it was the coil so I took the coil off of the 520 and put it on the 518 I tried to start the 520 but it would not start with the coil from the 518 so I said great the coil must be bad ! But the 518 still would not start with the coil from the 520?

So I put the coils back in there own machines. Now my 520 that was still running before I tried this swap also would not start? So I thought maybe the coil I put in the 518 did some damage to the good one. That is where I started to try and find some help on line as the only wheel horse dealer is 60 miles from me and wasn't helpful at all with giving me any information.

When I found Red Square someone told me to check my wiring and low and behold I messed up and had crossed the wires on the coils ! My Bad! When I straightened out the coil wires my 520 started !! So I left the 520 alone as I didn't want to do any more damage as Km3h had told me to do. At least I had one tractor back to running.

I was not getting spark on my 518H

My 518H I purchased new in 1986 and the tractor had no problems all these years until this time , just routine maintenance. So all the wiring on the machine had never been fooled with.

Now I'm only talking about my 518 . My 520 is out of the picture.

I thought the ignition module was bad that is when I pulled the fly wheel and tried to test it and started looking for a way to bench test it. SaveOld Iron had a post on how to do this , but I could not get it to test right. So I ordered a module and installed it . The tractor started right up ! So I thought I had it licked. It ran for 20 min and quit again? That is where all my headaches began. I went through all the wiring many times had almost the whole machine apart. I started replacing things as that is what the local dealer told me he would do any way if I brought it to him.

No matter what I do the tractor will not run for more then 20 min or so and die and will not reassert until I let it sit for 1/2 hr.

So I ordered the Hurley coil to see if that would work , thinking the coil was heating up.

This is where I'm at ! I have replaced the ing module, ing coil, key switch, starter solenoid, gas filter .Have dismantled the carburetor completely and cleaned and checked inside and out . Have taken all micro switches off cleaned every switch and contact and all wires and contacts several times .Rang each wire to clear. Checked and cleaned all grounds .

Changed all fuses . And the machine still will not run more the 20 min at a time. At one point I ran a hard wire from the positive side of the battery to the positive side of the coil and disconnected the wiring harness and I got the tractor to run for over an hour , but I could not make it happen again. Don't know if it was just a fluke or what.

So now I just use the machine for 20 min and put it away. I have it down to a point that I know when It is going to die (NUTS)

If I'm not saying this right or posting it right please let me know and I will post it some where else?

  Thank you all for your time and help

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