Onan P218G won’t start

[JaysHorse 287]

I have the OM and I was going to trace through the wires. Honestly I’d like to rewire it all and do away with all those stupid safety switches. 
 

As far as the letters and wire connection. I had the wrong switch in it before and had to make an adapter to switch the wiring configuration. I never harmed the original socket though. When I ordered the new switch I ordered the correct ignition switch for my machine. 103990

[JaysHorse 287]

I have a 416-8 with the Onan. I am tempted to snag the ignition switch from that to see if that one works.   

[JaysHorse 287]

So I can get it to fire occasionally when I have the key between the start and run position. Even with a known good ignition switch. I am so baffled right now it isn’t even funny. I know when I figure this out it is going to be something so stupid I am going to want to high five myself to the face. I’ve tried leaving the key in the run position and using a screwdriver to jump the starter but she just cranks over. 
 

does anyone know of a way to try and hook up a temp ignition switch and bypass everything? Also I thought I read somewhere that the engine can run with no condenser but may not with a bad one hooked up. Anybody have any on-site on that?

[RED-Z06 2,221]

7 minutes ago, JaysHorse said:

So I can get it to fire occasionally when I have the key between the start and run position. Even with a known good ignition switch. I am so baffled right now it isn’t even funny. I know when I figure this out it is going to be something so stupid I am going to want to high five myself to the face. I’ve tried leaving the key in the run position and using a screwdriver to jump the starter but she just cranks over. 
 

does anyone know of a way to try and hook up a temp ignition switch and bypass everything? Also I thought I read somewhere that the engine can run with no condenser but may not with a bad one hooked up. Anybody have any on-site on that?

Put a meter on the + side of the coil and move the key (other probe grounded) until it shows 12v...12v there means the key works 

[JaysHorse 287]

48 minutes ago, RED-Z06 said:

Put a meter on the + side of the coil and move the key (other probe grounded) until it shows 12v...12v there means the key works 

Yep I got 12v there with key turned on. I think I’m calling it quits for tonight. I guess tomorrow I will pull the coil off my other tractor and give that a shot. Maybe this one is just intermittent. Tested out ok but that don’t always mean anything I guess. 
 

I should also note that when I pulled the ring off behind the flywheel with the magnets one of the magnets fell out. I’m wondering if when I stuck it back in the plastic ring I didn’t get the poles correct. Thoughts…….?

[lynnmor 7,310]

2 hours ago, JaysHorse said:

 

I should also note that when I pulled the ring off behind the flywheel with the magnets one of the magnets fell out. I’m wondering if when I stuck it back in the plastic ring I didn’t get the poles correct. Thoughts…….?

 

Get a new ring.  If you have the old black plastic type, they had issues.  The newer gray type is reliable.

[Handy Don 12,238]

6 hours ago, JaysHorse said:

Yep I got 12v there with key turned on. I think I’m calling it quits for tonight. I guess tomorrow I will pull the coil off my other tractor and give that a shot. Maybe this one is just intermittent. Tested out ok but that don’t always mean anything I guess. 
 

I should also note that when I pulled the ring off behind the flywheel with the magnets one of the magnets fell out. I’m wondering if when I stuck it back in the plastic ring I didn’t get the poles correct. Thoughts…….?

One badly-placed magnet will reduce the power output of the stator for charging and lighting but would have no effect on start/run.

The condenser is mandatory, without it there will be no spark. If you have spark, ignore the condenser except to check that is it grounded and its connection to the coil is electrically sound.

It sounds to me like the coil + terminal may not have 12v power while the key is in the Start position, despite its having power in the Run position. Again, is the ignition switch correctly wired?

 

[cleat 6,078]

The Onan engine in your machine has the condenser connected to the positive side of the coil. It should not affect running too much connected or not.

I believe it is to prevent unwanted spark when just turning the key on or off that might cause a backfire.

 

Here is the troubleshooting from the manual for the module.

 

Troubleshooting the electronic ignition module for P Series.pdf

 

 

Edited December 31, 2021 by cleat

[JaysHorse 287]

37 minutes ago, Handy Don said:

One badly-placed magnet will reduce the power output of the stator for charging and lighting but would have no effect on start/run.

The condenser is mandatory, without it there will be no spark. If you have spark, ignore the condenser except to check that is it grounded and its connection to the coil is electrically sound.

It sounds to me like the coil + terminal may not have 12v power while the key is in the Start position, despite its having power in the Run position. Again, is the ignition switch correctly wired?

 

I didn’t mean the flywheel magnets. Yes the switch is wired properly because that is still original

[RED-Z06 2,221]

1 hour ago, Handy Don said:

One badly-placed magnet will reduce the power output of the stator for charging and lighting but would have no effect on start/run.

The condenser is mandatory, without it there will be no spark. If you have spark, ignore the condenser except to check that is it grounded and its connection to the coil is electrically sound.

It sounds to me like the coil + terminal may not have 12v power while the key is in the Start position, despite its having power in the Run position. Again, is the ignition switch correctly wired?

 

Performers used an independent hall effect pickup with a keyed reluctor ring to trigger.

[JaysHorse 287]

2 hours ago, Handy Don said:

One badly-placed magnet will reduce the power output of the stator for charging and lighting but would have no effect on start/run.

The condenser is mandatory, without it there will be no spark. If you have spark, ignore the condenser except to check that is it grounded and its connection to the coil is electrically sound.

It sounds to me like the coil + terminal may not have 12v power while the key is in the Start position, despite its having power in the Run position. Again, is the ignition switch correctly wired?

 

I didn’t mean the flywheel magnets. Yes the switch is wired properly because that is still original

[JaysHorse 287]

So after hooking the red wire of ICM to 12v and grounding my black lead of VOM and the red lead of VOM to black lead of ICM and turning the engine over by hand it does not switch from 1vdc to 12vdc as per manual for testing. I guess off comes the flywheel again. And possibly replace the ICM and trigger ring. 

[JaysHorse 287]

Update……

 

Found another way of testing the ICM and that seems to be working good. All voltages to the coil are what they should be per the manual. I guess really the only other thing to check at this point is swap out the coil and wires. 

[JaysHorse 287]

Well the mystery has been solved. Turns out it is the coil that is bad. I use the one from my 416 and she fired right up. Now to fix the intake for the forever surging I’ve dealt with. Thanks for everyone’s help. 

[JaysHorse 287]

After some patience she’s ready to haul firewood and blow snow!!

[Snoopy11 5,714]

21 hours ago, JaysHorse said:

Turns out it is the coil that is bad

I have been quietly sneaking around...

 

So... @JaysHorse... I think it is worthy to ask... earlier in the thread when you said that you had spark... how exactly did you know that you had spark...

 

I am thinking... maybe you were seeing (weak) spark if you did a visual check...

 

(Just want to clarify this for further readers... just in case).

 

Don

[JaysHorse 287]

19 hours ago, Snoopy11 said:

I have been quietly sneaking around...

 

So... @JaysHorse... I think it is worthy to ask... earlier in the thread when you said that you had spark... how exactly did you know that you had spark...

 

I am thinking... maybe you were seeing (weak) spark if you did a visual check...

 

(Just want to clarify this for further readers... just in case).

 

Don

Don, 

       I did the visual check and saw a spark. I also checked the coil per manual and all checks checked out correct. I could also get it to fire when I would fiddle around with the ignition key switch. That’s why at first I thought it was that but that wasn’t the case. Then I moved on the check the ICM (ignition control module) and that failed the check. So I removed that and cleaned it up and checked it using the above picture method and that worked properly. Put everything back together for what felt like the hundredth time and still nothing. Luckily I have another Onan machine and robbed the coil and wires and she fired right up. I put my old wires on and she still fired up. Leads me to believe it was the coil all along. The real butt scratcher is the oils coil checked out fine with the resistance checks. 

[Snoopy11 5,714]

59 minutes ago, JaysHorse said:

Don, 

       I did the visual check and saw a spark. I also checked the coil per manual and all checks checked out correct. I could also get it to fire when I would fiddle around with the ignition key switch. That’s why at first I thought it was that but that wasn’t the case. Then I moved on the check the ICM (ignition control module) and that failed the check. So I removed that and cleaned it up and checked it using the above picture method and that worked properly. Put everything back together for what felt like the hundredth time and still nothing. Luckily I have another Onan machine and robbed the coil and wires and she fired right up. I put my old wires on and she still fired up. Leads me to believe it was the coil all along. The real butt scratcher is the oils coil checked out fine with the resistance checks. 

I 'tink that your thread is going to help someone else in the future, for sure!

 

Don

[JaysHorse 287]

1 hour ago, Snoopy11 said:

I 'tink that your thread is going to help someone else in the future, for sure!

 

Don

I hope so. The coil test was kind of like a false positive COVID test. 😂

[Handy Don 12,238]

2 hours ago, JaysHorse said:

The real butt scratcher is the oils coil checked out fine with the resistance checks. 

That is frustrating. Very lucky you had a "probably good" to test with as you narrowed things down. Must be some sort of intermittent or conditions-related failure on the "bad" coil. Good job sniffing it out.