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Sunstar dies when removed from neutral


Tarheel

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Tarheel

 A couple of weeks ago maybe, I noticed that my Sunstar would want to die when I moved the shifter away from neutral. I'd press the brakes on and off or move the PTO switch around and even move around on the seat until all at once it worked as it should. After a while, it seems to me that none of the things I've been doing has had any real effect and the problem seems to be getting worse.

 Has anyone seen this problem before ? Thanks.

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SmilinSam

Could be the safety interlock module, or a safety switch, or corroded &/or loose wires in the safety circuit.  OR even  combination of all of the above.

You can narrow things down by finding out what each part of the safety system does. IE.. locate what switch functions work to actually kill the engine. My guess would be the seat safety in conjunction with the motion control safety, but dont know that for sure.

You also  cant just assume all safety switches do the same things in all tractors. For instance across the years and models a seat safety will do different things. One might kill the engine when you get off the seat, while another might leave the engine running while it just shuts the blades off ( electric clutch models)when you leave the seat.

In general , prior to interlock modules most all safety switches were wired in series to prevent the tractor from being started if any of the switched were open. This started with 2 main safety switches,  the PTO safety  and motion safety. Eventually a seat safety was added, and then also a brake pedal safety.    Fairly simple and  straight forward from around the late 60's into the mid 80's

Then the Interlock modules came into play. Interlock modules are what makes it possible for combinations of safety switches to do different and more complicated things as well. Prior to the IM modules people could bypass or repair any or all  of the Safety problems without too much trouble.  With an IM module you HAVE to have the IM module to make the system work. NOW,  swapping out IM modules is often not going to mean a fix. I have run into many instances where there is nothing wrong with the IM. Its  bad safety switches,  or corroded/ broken /loose wires going to the IM thats the problem.

Corroded wires is the worst. Wires can look ok from the outside, Usually you can see a little green, black  or other at the ends where the connections are. Sometimes you can cut the wires off and get good clean copper. But most of the time  you cut it back and the wire is just dark or even just black from corrosion... and all the way through the wire. NO Fun to repair/replace....

 

Probably over communicated things here, but it IS good knowledge to have...

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PhanDad

@SmilinSam is right on.  IMO SunStar interlock system is much worse than "newest" Sovereign.  

Al's thoughts:

HI, These tractors have a complex wiring system, at this time High Tech was the byword. Ariens came out with the HT (Hi Tech) tractors about the same time. Their wiring is a nightmare also. Simplicity saw the advantage to a simple system with the advent of the Legacy. The Sun Star has a number of separate grounds and one of the more common problems is poor grounds. Be sure the interlock module ground is good and as I remember, there are 2 or three more gound spots on the firewall. Sounds like it could be the module. The later and replacement modules have less problems. If you have one of the early modules and get a new one, the plug needs to be turned over to plug in. DO NOT BEND TABS etc to get it to plug in. Al Eden

See these posts for some info:

https://simpletractors.com/forums/topic/40299-sunstar-electric-clutch-resolved-thanks/

https://simpletractors.com/forums/topic/61058-simplicity-sunstar-electrical-issue-desperatly-needing-help/

 

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If I remember correctly, there was a unit that plugged into the wiring on these tractors to assist with diagnostics. I remember seeing one for sale a few years ago. I can’t remember if it was eBay or CL. It looked pretty cool but I have never owned a Sunstar & don’t know how well those diagnostic units worked. I figured someone here may have bought it.

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Thanks to all of you. I have one of the tools to read the interlock module, but it is old and hasn't been used in 30+ years. Guess i can only try. As I recall, it cost me a great deal (Near $400 back around 1990 if I recall correctly) I may have used it 3 or 4 times.

 I'll try it after I bypass the seat switch. The ground issues and the corroded wires catch my attention because this is the machine the battery blew up in. I'll let you know what I find. 

 Thanks again guys !

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 Can't seem to get around to the Sunstar again. But the garden lacks only a row of Okra now (And putting up the electric fence for the deer) and tonight I finished putting the Honda GX160 on the compressor back together. It runs well but vibrates really bad. The fuel cap came off at one point and it leaks badly anyway. I'll remove the drive belt and then the pulley if need be. I have a new fuel cap ready to order.

 

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Tarheel I removed my interlock module on my AgcoAllis and the secondary solinoid. I went way overboard on the wiring but other then occasionally odd starts where the ignition switch won’t engage recently. Up until recently I've never had an issue.  and all my gauges work.  I also turned my seat safety into the rear pto wiring, and installed a rear pto switch. All safety’s work like a 7100 series, including the rear pto switch. 

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Hurleyii, This may well be a problem with the interlock. It seems it is more a time delay than anything else but I don't know the modules enough to know if they have such or maybe a relay that is taking time to work. I may be able to get it in the shop tonight and look into it a bit.

 Thanks for the input.

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Tar Heel I pressure washed mine yesterday and discovered my signal wire from ignition at starter location is stupid loose and had actually fallen off from the pressure washing or before and was the reason I was having a momentary delay for starter engagement or none at all and had to jump it out. I also discovered all though I disabled the second solinoid it’s still mounted to the tractor. Was very confused when I first discovered it cause apparently I just cut the wires off . I was like it’s till wired, wth I swear I removed it. After feeling the bottom side I realized the wires were all cut. 

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