Noob Question: Should the Engine Stop Switch Ever Be Switched Off?

[Twism86]

[DEcosse]

Originally Posted by Orangeman

I am more than willing to learn, could you please show me ........

The challenge was for you to support flawed theory, not for me to support mine

However, here it is:
slightly different revision (fuel pump relay added)* but the salient part is the same - as it is on virtually all the FI Triumphs
The current flow path is in bold red with 'conventional' current indicated by the arrows; the ignition power circuit goes through the key-switch then out through the fuse directly to the Kill/Run switch - note that there are no other off-shoots* between the Key-Switch and the Kill/Run switch - as stated, these switches are directly in series and breaking either does exact same thing. NONE of the other poles on the key-switch has anything to do with the ignition circuit.




* I acknowledge that on the later revision they added the ignition feed off the key-switch directly to the Fuel pump relay - this does not change anything as far as shut-down sequence goes.
That input to the FP relay could equally be un-switched (constant) power - in order to supply the pump itself, the control comes from the ECM on the 'low' side of the coil.
Note that shutting off the Fuel pump alone however does not kill the bike - there is still Fuel Pressure in the Rail.
Also note that regardless of there still being power to the input side of the Fuel Relay Pole, the ignition power to the coil (the Red/Green) comes from the output side of the Kill/Run switch (via the Alarm interlock) - so turning off either the Kill OR the ignition will shut off the FP relay regardless of what the low side of the coil is doing, or whether the input pole is powered or not

[masa]

Originally Posted by DEcosse

I will also add that there is no constant power to the ECM - therefor what you are suggesting is that if bike is parked for an hour, that adaptive trim is lost? Don't think so!

The Key-switch and Kill/Run switch are directly in series with each other, with no parallel branch nodes off the connection between them; so when power is broken at either one, there is no way of the ECM possibly knowing which it was that removed the power from the circuit

Hi, DEcosse,
I don't have the schematic for neither the bike or the ECU, and I'm not willing to crack open my ECU just to see what chips are inside but if it has flash memory, then yes, it doesn't need power to retain the adaptive values. But then they could be overridden after the bike is turned off as the unit could be backed up by a capacitor, allowing it to operate long after the bike is turned off.

And yes, the ECU probably can't directly tell if the kill switch is on or off, but it is connected to a dozen different things and is able to tell which one is at what state. The instrument cluster for example doesn't turn off when the kill switch is cut off and it can most likely tell that. It should be easy to program the ECU so it operates differently depending on the state of the cluster.

So in general, it is possible for an ECU to operate differently when the kill switch is used. But I don't know if this particular unit does that (I doubt it) and I don't see any reason someone would program it so using the kill switch is harmful. There is still a possibility of a bug, but that's like worrying about the side stand breaking in half.

[Orangeman]

DEcosse,
I appreciate your explanation. I (rather politely if I must add) asked because you have helped me with other non related issues in the past. It was explained to me as noted previously by a Triumph rep so the challenge was not mine to accept or deny, just to sit and learn

.

[DEcosse]

Originally Posted by Orangeman

I (rather politely if I must add) asked

Sincere & humble apologies on my part - read more into the request than was actually written

Originally Posted by masa

.... The instrument cluster for example doesn't turn off when the kill switch is cut off and it can most likely tell that. It should be easy to program the ECU so it operates differently depending on the state of the cluster.....

The instrument cluster back-lighting does not turn off with the Kill/Run - that is an ancillary circuit (part of lighting circuit), nothing to do with control circuit and the ECM is clueless (and rightly so) as to whether those lights are on or off.

There is no need to open up ECM, just look to the schematic posted and see that there is no constant power to ECM, nor any power that is applied to the ECM that is not controlled by the Key-Switch/Kill switch.

One interesting feature of the ECM power control - the ECM relay (22 or 23 depending on which schematic generation above you are using) - switches power from constant source back out to itself and to the coils, injectors etc; you will notice that when you turn off (either ignition OR Kill/Run) that the ECM relay does not drop out immediately - that click you hear a few seconds after you stop by whichever method - because the shutdown sequence keeps it latched while it writes to memory. That latch is controlled by the primary ignition circuit input (pink input per my second marked-up diagram) - and that is turned off by EITHER the Kill or Key.

Red is the ignition power circuit
Orange is constant power to the ECM Relay
Yellow is ECM controlled Latch for ECM Relay
Brown is ECM Relay output power.

[masa]

Originally Posted by DEcosse

The instrument cluster back-lighting does not turn off with the Kill/Run - that is an ancillary circuit (part of lighting circuit), nothing to do with control circuit and the ECM is clueless (and rightly so) as to whether those lights are on or off.

My instrument cluster seems to be working beyond just back lighting though. The temperature gauge and gear indicator is working properly when the run switch is off. I don't have the wiring diagram/key table in hand so I can't tell but aren't the gear position sensor and the coolant temperature sensor hooked to the ECU, not directly to the instrument cluster?

[DEcosse]

I don't see how that is possible when both signals are processed by ECM and output on the CANBUS. Ignition power into the cluster also goes off with either Key-Switch or Kill.

[Orangeman]

Does it have anything to do with the added branch from the input side of the stop switch to the instrument cluster in the Street Triple diagram but not in your original ?

Just checked and my cluster also stays fully active with the stop switch off, you can toggle gears and it updates, also maintained the temp reading after the bike was started and shut down with the switch ?

For verification...please note stop switch is in the off position.

[masa]

Originally Posted by DEcosse

I don't see how that is possible when both signals are processed by ECM and output on the CANBUS. Ignition power into the cluster also goes off with either Key-Switch or Kill.

There got to be somewhere the cluster and the ECU is getting the power. Or maybe my bike was made on a Friday at 4:00PM and is wired differently

[OregonScrambler]

Originally Posted by triplestrength

It's in the same circut as ignition so shuts engine down as normal but can leave lights on so better to use ignition switch.
Urban myth that kill switch is harmful to engine settings.

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This exactly, they are part of the same circuit. Generally battery-key switch-kill switch. It makes absolutely no difference, the only thing that will get more wear is the switch

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