Old Dirty Feta and the MS500i--the Hi-Tech Wood Lobotomizer

[beaglebriar]

From the way I see it on the saw, the only way RPM can be determined is by sensing position of the flywheel/crank. More than likely there is some confusion between the timing for spark with the timing for the injector.



Won't dropping the cylinder potentially have the same effect, Kevin? I'm curious how the injector timing and the spark timing are separately determined. My brain goes directly to crank timing.

Offsetting the cylinder up/down, would change the port timing, which could cause the injector to potentially spray fuel at the incorrect time also.

In order to optimize port window availability, an adjustment in fuel delivery may be mandatory.



It doesn't seem possible that spark isn't directly relevant to crank position. I would agree that injector time can vary according to RPM.

The piston moving up and down in the cylinder isn't visibly metered by this saw. In other words there is no piston position sensor. The only way to determine RPM is via crank revolutions (i.e, RPM's).

I'd like to get my hands on Stihl's "theory of operation" files.

Kinda the same thing I've been thinking. Simply doing a standard port job might not be enough on these. It'll probably require programming changes.

 

[Stump Shot]

Kinda the same thing I've been thinking. Simply doing a standard port job might not be enough on these. It'll probably require programming changes.

Was my first thought about these saws, but how to get a programmer made for it?

 

[Leafy]

Was my first thought about these saws, but how to get a programmer made for it?

Pull the electronics and see if there's any exposed contacts like test points or programming ports. If not reprogramming is probably going to require depotting and we'll end up better off just adjusting the computer by tricking the inputs or directly changing the outputs.

 

[Simondo]

Updates, updates, updates....the tale of running a high tech saw forwards and backwards. Yes, backwards.

So, I fired up the 500i after it I had ran it for a while yesterday. It was about 88f and the saw had sat in the sun for a bit.

Since there is no High Idle or choke on these, the chain is never spinning until the operator actuates the trigger. It rumbled to life.

I let it run a for a few seconds and then hit the trigger. Low and behold, the chain spun backwards. Not sure if it has done this before.

It ran quite crappy for another 30 seconds and died. On the next restart, it regained it's orientation and ran in the right direction.

Fishy stuff. I'm wondering what can cause it to run backwards. I've often noticed that on an initial start it will run and die. Never noticed the chain spin backwards though.

I've got some investigating to do. Any thoughts?

Did you move the timing from the standard position on the flywheel ?

 

[AlfA01]

Did you move the timing from the standard position on the flywheel ?

Timing is stock. I had advanced it briefly, but it seemed to have a negative effect on performance.

 

[beaglebriar]

Was my first thought about these saws, but how to get a programmer made for it?

Gonna take someone a helluva lot smarter than me. [emoji23]

 

[AlfA01]

I haven't ran it today, except just to see if I could duplicate the problem. Started and ran 100% normal today.

I must add the saw is running like a top. I mean it screams. I even threw it on the mill to see how it would handle it.

I'm impressed with the way the saw performs. The backwards spinning chain vision has got me scratching my head though.

 

[beaglebriar]

I haven't ran it today, except just to see if I could duplicate the problem. Started and ran 100% normal today.

I must add the saw is running like a top. I mean it screams. I even threw it on the mill to see how it would handle it.

I'm impressed with the way the saw performs. The backwards spinning chain vision has got me scratching my head though.

View attachment 183670

First ever backwards running 500i in the WORLD!!??

 

[AlfA01]

Kinda the same thing I've been thinking. Simply doing a standard port job might not be enough on these. It'll probably require programming changes.

Reprogramming might help, but I'm curious on the capability of the electronics to learn (ie correct for various conditions and remember), or if the system resets to factory defaults (ie firmware in the circuit chips).

There's no battery I have seen yet in order to retain memory and the FI is powered by inertia of the flywheel around the generator ring.

Was my first thought about these saws, but how to get a programmer made for it?

Yep. Same as a we talked about before, Steve. Right now, this thing has got me a little stumped, Stump!

 

[AlfA01]

First ever backwards running 500i in the WORLD!!??

WORLD? Lol. In the whole entire Fecking galaxy, DJ! LMAO.

 

[dall]

Gonna take someone a helluva lot smarter than me. [emoji23]

maddie my dog said she didnt know either

 

[Woodpecker]

There's no battery I have seen yet in order to retain memory...

Dan would a solid state memory chip require a battery? I don't think those little micro sd cards have batteries.

 

[huskihl]

First ever backwards running 500i in the WORLD!!??

.

 

[AlfA01]

Dan would a solid state memory chip require a battery? I don't think those little micro sd cards have batteries.

That's an idea. I'm sure there is a chipset of some sort that stores the firmware.

 

[VinceGU05]

I stated it before that a timing advance wont help anything on this saws.

does it on the 462?

 

[ferris]

does it on the 462?

It will help on the 462, but be careful and advance only a small bit.

 

[blsnelling]

Very strange, with both the backwards running and dying at idle. Not to be Debbie Downer, but this is the most un-cold natured saw I have ever seen. This one starts super easy, idles perfectly, and has instant throttle response immediately after starting cold. Of course, yours had a LOT more run time on it for you to experience how it runs on a longer term basis.

 

[blsnelling]

Kinda the same thing I've been thinking. Simply doing a standard port job might not be enough on these. It'll probably require programming changes.

I've seen nothing with either MTronic or this 500i to suggest that anything needs re-programmed.

 

[huskyboy]

Just a thought, since you filed the keyway and presumably put it back to stock after seeing it not help.... maybe it slipped causing the issue your having?

 

[blsnelling]

How many times are you pumping the primer before starting? I haven't read the manual but have been pumping 8 times.