choosing -chinee- coil replacement anyone's experience
- Thread starter unknwn
- Start date
Help Support Arborist Forum:
cstair2000
ArboristSite Lurker
I keep several of the cheap coils around for my MS 361 and my 2 Farmertec knockoffs. They do fail and OEMs fail too.
SteveSr
Addicted to ArboristSite
It sounds like you got it hotter than normal with that kind of usage. However, I don't believe that the M-tronic system has any temperature sensors but thermal expansion can break bad/weak electrical connections. I would also unplug each connector in the harness and hit both pieces wiith electrical contact or brake cleaner.
While it is running I would start by gently pulling/tugging on all of the connections/wires in the wiring harness and see if you can make it die. I think that the system will also kill the ignition if the solenoid faults open circuit. If you have the older solenoid/white fuel filter you might want to upgrade first to see if this makes your issue go away. I would also check the kill switch for any foolishness.
For a long shot make sure that you have the correct Stihl specified resistor spark plug type installed. This will help prevent electrical interference which may interfere with the M-tronic computer.
Yes of course. As SteveSr already said there is more technology in it than in an normal ignition module.
Of course there is a temperature sensor in the control unit. The temperature is taken into accound regulating the engine.
It depends on the age of the saw. Versions without m-tronic 3.0 had 1145 400 4711 (nla) replaced by 1145 400 4702. Versions with m-tronic 3.0 use 1145 400 4713.
SteveSr
Addicted to ArboristSite
I am sorry, I don't know how this could work, at least not work very well. For relevant temperature sensing the sensor should be as small as possible keeping its thermal mass to a minimum. This would allow the sensor to respond in a timely manner (thermal time constant) to a given set of conditions. The thermal sensor also needs to be in intimate (close) contact to the quantity being measured.
So if there is a temperature sensor inside the ignition module then what parameter is it actually measuring? The temperature of the ignition module is determined by at least 4 things:
1. The heat generated by the internal electronics in the module.
2. The heat conducted into the module through the mounting bolts and steel coil armature.
3. The heat radiated into the module from the engine / crankcase.
4. The temperature of the ambient air as it is forced across the module by the flywheel fan. Another variable to this is that the airflow changes rather dramatically based on engine RPM.
So no, I don't believe that Stihl is doing this, at least to control/adjust engine operation. Now, do they have a last chance "kill switch" temperature sensor in the module? That is a subject for another discussion. Here again, I suspect not, due to the long thermal time constant (response time) of the ignition module mass. The engine is likely already dead/damaged by the time the module would get up to the trip temperature.
Believe it or not, there is a temp sensor in it:
"By monitoring of the engine temperature and speed,
the control unit continually checks the operating
state of the chain saw and adjusts the fuel flow for
constant optimum engine performance"
"By monitoring of the engine temperature and speed,
the control unit continually checks the operating
state of the chain saw and adjusts the fuel flow for
constant optimum engine performance"
SteveSr
Addicted to ArboristSite
Sorry, that looks like "marketing speak" or wishful thinking, or perhaps a different system... i.e Show me the sensor!
I have no picture of the sensor, because I can`t open the control unit. Here is a copy of an old diagnostic report of an FS 460 C-M I often work with. Temp during data readout was 60.8°F!!! I would not say this if I would not know this to 100%!!
MDG1 Diagnoseprotokoll
Kunde:
Kundennummer:
Händlerdaten:
Händlernummer:
Maschinenauswahl: Maschinennummer
FS 460 C-M
Techniker: Datum:
02.05.2016
Geräteeinsatz: gewerblich privat Garantiekarte vorhanden: Ja Nein
Identifikation
Teilenummer Steuergerät: 4147 400 4701
Teilenummer Software-Version: 4147 451 1000 C
Sensorik:
Temperatur Steuergerät: 16 °C | 60,8 °F
Betriebsdaten
Betriebsstundenzähler: 326:58:37
Startzähler: 1228
Motormanagement
Tastverhältnis Leerlaufregler: 42
Tastverhältnis Volllastregler: 53
MDG1 Diagnoseprotokoll
Kunde:
Kundennummer:
Händlerdaten:
Händlernummer:
Maschinenauswahl: Maschinennummer
FS 460 C-M
Techniker: Datum:
02.05.2016
Geräteeinsatz: gewerblich privat Garantiekarte vorhanden: Ja Nein
Identifikation
Teilenummer Steuergerät: 4147 400 4701
Teilenummer Software-Version: 4147 451 1000 C
Sensorik:
Temperatur Steuergerät: 16 °C | 60,8 °F
Betriebsdaten
Betriebsstundenzähler: 326:58:37
Startzähler: 1228
Motormanagement
Tastverhältnis Leerlaufregler: 42
Tastverhältnis Volllastregler: 53
I too would like to see how temperature is monitored. If it senses ambient air temp there would have to be the bead end of a thermocouple visible in the air stream coming off the flywheel. The only other meaningful temperature would be the cylinder head temp and there should be an obvious sensor attached to the cylinder with leads going somewhere. Measuring the internal temp of any module makes no sense at all. Anyone have a wiring diagram for this saw?
SteveSr
Addicted to ArboristSite
Very interesting! From what I recall the FS-460 is a super-sized weedeater / clearing saw and not a chainsaw. So what happens when you hook the computer up to an M-tronic chainsaw? Does it still show the temperature then as well?
Yes, m Tronic is m Tronic.
TRANSLATION (thanks to Google):
MDG1 diagnostic protocol
Customer:
Customer number:
Dealer data:
Dealer number:
Machine selection: machine number
FS 460 C-M
Technician: Date:
05/02/2016
Use of equipment: commercial private Guarantee card available: yes no
ID
Part number control unit: 4147 400 4701
Part number software version: 4147 451 1000 C
Sensor technology:
Temperature control unit: 16 ° C | 60.8 ° F
Operating data
Hour meter: 326: 58: 37
Start counter: 1228
Engine management
Duty cycle idle controller: 42
Duty cycle full load controller: 53
