I like how the Stihls start. Push the switch all the way down and pull until it freakin' starts. Simplest I've ever seen on a saw. I've messed with a couple AT Huskies and I hear what you're saying. And they should run just fine with a standard carb. Most of the Stihls have not MT versions of the same engine that were either released in other countries or were prior models to the current line-up.
I can start my old school Stihl 026 but it takes a sharp ear to hear that first burp or I flood it. My Husky 555 with the autotune is a breeze. One or 2 pulls and even if I don't hear it I can see the compression release has popped up. Take it off choke and the next pull it is running. I'll take the "modern technology" every time.
My AT saws start right up also. You just need to set high idle when they are warm but they start right up.
It couldn't hurt. If I am restarting within a couple of minutes I just pull the cord but if it has been sitting aside for 5 or 10 minutes the high idle gives a more consistent first pull start.
I get what you're saying, but my 3 standard carb saws start predictably and warm start on the first pull too. So I'm not sold on electronic tuning either way. David
Has anyone make progress on reverse engineering the interface? I recently heard from a dealer that the autotune software is useless for consumers because Husqvarna now requires the software to log into the Husky dealer website to function. Being an EE and a Ham Radio operator I am used to reverse engineering software protocols and building hardware interfaces. Just need a place to start.
I have to wonder if it wouldn't be easier to just drive the OEM hardware with a replacement control module that would bypass the OEM module. You would give up access to the OEM data-logging but gain total control over the fuel and ignition functions.
I've run into the same issue. I bought the Diagnostic Tool and I can't find a copy of the CST and even if I had it I don't have a computer that can run it. I have a Mac and a Linux machine. I took apart the Diag tool and it's pretty simple inside. There's a FTDI USB to RS232 chip (at TTL level) connected to an Atmega164P 8-bit microcontroller and some output hardware. Not much else.... all the components are on the top of the board and it appears to be only a 2 layer PCB, but I haven't checked closely. Datasheets are available on the mfg websites. I'll pin the thing out and draw up a schematic later. The hard part is the protocol (as someone said). I have some ideas on how to deal with that... but its very labor intensive. I also haven't figured out what interface the saw per-se uses... with only 3 pins... well, its unclear to me what would make sense there. I have to do some poking around. It would be really nice if Husqvarna published an ICD for that interface. I don't know why companies consider this proprietary or whatever. If I have to face this kind of dealer-lock-in-money-suck it is basically a deal killer .... I will never buy another product of theirs. There's a reason I own a Kubota instead of a Deere and didn't even look at one. Deere is the worst for dealer repair lock-in.
This thread has convinced me that I won't be getting a computerized Husky. Too complicated and too much trouble just to run a small engine and pull a chain around a grooved bar. I will say though that I am beginning to like my little Stihl 261 CM, and once I learned the right way to start it, I find it to be very user friendly on the starting up, etc. But that is as far I ever want to go on electronics to run small engines.
I think you’ve already crossed the line with the Mtronic And I agree, except for legacy known issue on a vintage of the 550XP, I find them very user friendly
I would guess the 3 wires are Rx , Tx , and ground. Protocol is probably logic level UART. I would watch the signals with a scope to determine the baud rate. If it logic level signals you need to get it back to RS-232 levels so you can connect to a PC running something like realterm. SparkFun RS232 Shifter - SMD - PRT-00449 - SparkFun Electronics Need this is the signals are logic level. RealTerm: Serial/TCP Terminal Realterm can log the entire data exchange if you set it up correctly. Be prepared for the possibility that there is a basic encryption on the communications. If you find that sending the same request repeatedly causes different data to be exchanged each time then this is likely the reason.
What I haven't thought through is how the chip on the saw is powered if there are only three lines: Tx, Rx and Ground. Presumably its powered by the saw when the engine is running, but its unclear to me how long it could run w/o a super cap or battery or external power while you are trying to talk to it. I also don't know yet if its 1.8v, 3.3v, 5v or RS232 (-12 to -25 swing). There are ways to power via logic lines, but that's pretty atypical. I'll know more as I dig into the board. If someone has a spare auto-tune carb that they want to sacrifice to the cause, I'm more than happy to take that apart and see what the electronics on-board look like.