550XP Autotune Issues..

Andyshine77

Andyshine77

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Some have had success using the existing module on the original carb and attaching it to the new one, as the new carbs come with no programming and the program in the carb module has to match the coil. The carb module itself does have programming along with the coil.

These saws are not fun to work on and in my opinion are meant to be used and discarded, built-in obsolescence, unless you have the equipment, which only dealer really can have. Hopefully Husqvarna got the memo and will allow the end user to have a simple interface to update firmware as needed.
 
Jeffkrib

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Some have had success using the existing module on the original carb and attaching it to the new one, as the new carbs come with no programming and the program in the carb module has to match the coil. The carb module itself does have programming along with the coil.

These saws are not fun to work on and in my opinion are meant to be used and discarded, built-in obsolescence, unless you have the equipment, which only dealer really can have. Hopefully Husqvarna got the memo and will allow the end user to have a simple interface to update firmware as needed.
Wouldn’t that mean all new pro saws with Autotune or Mtronic could be considered throw away?
 
Andyshine77

Andyshine77

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Wouldn’t that mean all new pro saws with Autotune or Mtronic could be considered throw away?
Yes and no, as the original 550 had other underlying design problems that could hit you later on down the road, which is why the saw was completely redesigned.

To an extent, whenever you're locked out of being able to repair a specific part or function of something you own, it has built in obsolescence. I say this because you're now tied to a service provider, which may or may not want or be able to repair what you have, and doing so is often not cost effective. As I type this they're currently lawsuits against some manufacturers, these lawsuits are for the "right to repair".
 
Motherboard

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yes in european courts too, pressure on the manufacturers to sell parts at reasonable cost, and open diagnosis software too
they will probably have to cave in because of the many copy parts that china make, and the cracked software that they sell
And the fact some manufacturers will sell you a part that won't work, until you hook it up to their computer, there is no
need for this whatsoever other than to charge an extortionate fee for sending out a service agent with a laptop to do something
that there is no call for, other than deliberate extortion, they can easily program the part to boot up and sync with the main board,
am talking tractors here, after all thats all the laptop tells it to do.
 
frank_

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And the fact some manufacturers will sell you a part that won't work, until you hook it up to their computer, there is no
need for this whatsoever other than to charge an extortionate fee for sending out a service agent with a laptop to do something
that there is no call for, other than deliberate extortion, they can easily program the part to boot up and sync with the main board,
am talking tractors here, after all thats all the laptop tells it to do.
most car injectors have to be paired to the ecu for calibration reasons, i dont think there is any way around that tbh.
its all down to ever stricter emissions targets basically
as long as the parts and diagnostics are affordable, then its just clever progress imo
2 strokes have come a long way, from 16:1 smokers with static spark ignition
 
Motherboard

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most car injectors have to be paired to the ecu for calibration reasons, i dont think there is any way around that tbh.
its all down to ever stricter emissions targets basically
as long as the parts and diagnostics are affordable, then its just clever progress imo
2 strokes have come a long way, from 16:1 smokers with static spark ignition
Yes, all the way from 16:1 to 50:1, and it only took about 80 years.
 
ajs2654

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Well just a status update. I dropped my saw off last week to another shop to get a second opinion on it. I got phone call today from the mechanic. In my notes, I put down issues may pertain to autotune reported by the first shop I had look at it. When he hooked it up to his diagnostics, he saw it was reading just fine so he questioning why I thought it was the autotune.. I told him about the compression reading 115 reported by the other shop. He saw he would check it out. Again, when I looked at the cylinder myself there was no significant scratches on the cyclinder other than some very light horizontal scoring and the piston looked great. Maybe the first shop didn't have an accurate compression tester..

So there might be hope!
 
ajs2654

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So after dropping it off to the second shop, I finally got some feedback on it. Ive been waiting almost 3 months for them to tell me that it has pretty low compression since they couldn't source the right compression tester. They haven't taken it completely apart yet, but he thinks its either the rings and so I might as well do a whole top end .. I feel like it just if the rings needed reaplaced, the cost would be significantly different from a whole top end. So I have three options:
1.) Let them go ahead with the fix. I doubt they are just going to tell me it's rings. I would assume it would be a least $400.
2.) Go ahead and try the fix myself. There is a pretty good video on Youtube that goes over step by step. I am somewhat mechinically inclinde, but I never replaced a top end before. Should I get OEM one, or after market one on ebay? Cost difference is significant.https://www.youtube.com/watch?v=kiZkcqmqe-M
3.) Don't put anymore money into it. Just sell as is. Not sure what I could get for it.
Thoughts?
 
SimonHS

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If it was my saw, and out of warranty, I would go with 2 and see if a new ring would fix it. This is the most cost effective answer, as long as you feel able to do it.

Once you get inside it you will be able to check the condition of the ring, piston and cylinder.
 
jchipps

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I wouldn't sink a bunch of money into it.
Sounds like neither Dealer really knows for sure what the problem is, and it could very well still be an issue with the auto-tune bells and whistles.
If you feel like doing some experimenting to get some saw building experience, go ahead and tear it apart.
You can then decide whether to do an entire top end on the cheap with after market parts, (not something I'd personally do) or just replace the ring with OEM ... that is, if you don't find any significant scoring once you get it apart.
If a simple ring job fixes it .... great!
If not, you'd probably be best to cut your losses and sell it for what it's worth, and get a more reliable saw that doesn't have all the computerized bells and whistles.
 
huskihl

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Take the ring off and orient it in the bore the same as it would be on the piston and push it up into the bore above the exhaust port using the piston to square it up and check the ring end gap.

Honestly, it doesn’t look like it has all that much time on it to me. I think the compression is probably fine and the ring gap is probably less than .015” and their adapter was the reason for the low compression.
 
SimonHS

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When you start the saw do you immediately blip the throttle to take it off choke? This also takes it off high idle. You could try pushing the choke lever in. I believe that this leaves the saw in high idle and might help it run. It's worth a try.

The autotune might be confused and need resetting. The best method for doing this is shown in this video by @afleetcommand and @spike60 . If you can get the saw to run, three minutes at idle and then 45 to 60 seconds WOT under load.

 
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