Feature request Push button start

[Turbo nut]

I have been asked if this can be done.

[aarc240]

The requirement needs to be fleshed out more as your 'simple' request is but one bone in a skeleton.

Maybe something that would:
prevent starting if the engine is already running
prevent starting in gear for an auto or require the clutch to be depressed if a manual
disengage air conditioning if that is still active
disengage nitrous if that is still active

What else?

One input (neutral or clutch safety switch and starter buton in series) and one output (starter relay) are required.
Are these i/o resources available and which ones are to be used for which purpose?

[Turbo nut]

I would think something like. Push button to activate starter relay for X amount of seconds (amount of time selectable) or untill reaching X RPM (again selectable). and possibly when starter button is pushed again it stops cranking.

[kjones6039]

I would think something like. Push button to activate starter relay for X amount of seconds (amount of time selectable) or untill reaching X RPM (again selectable). and possibly when starter button is pushed again it stops cranking.

aarc240's point is absolutely valid! You certainly don't want to activate cranking and then remember that the transmission was in gear or the engine was already running, among any number of other considerations. (hard on garage walls and starter drives, respectively)

Clearly, MS would need to monitor several conditions in order to accomplish this safely. Frankly, it doesn't seem too practical to me!

Just my 2 cents, of course..............

Ken

[kizzoalfa]

IN my understanding Megasquirt is an ECU. This function is fit for a BCM but not for an ECU. The ECU has to be part of the auto startup sequence by providing engine RPM information.

However you can impement the pushbutton start with the current ECU features: Build a simple timer like a monostable for 6sec by 555 timer. Start the monostable via a serial logic where you need at least clutch check. As you start the monostable start the starter motor. Wire an active low output from MS3 to 555 reset pin which beame activated if RPM>350 (specify it above to your crancing RPM by 100 - 150rpm) to disable starting motor.

Zoltan

[DaveEFI]

I have been asked if this can be done.

Why would you want/expect MS to do this? It has no control over the starter motor - and adding this would be pointless for most.

[Turbo nut]

Sorry if I struck a nerve with some of you. This was just something I was asked if MS could do. I have seen some new cars using this. MS does quite a few things that are not really needed to be handled by the ECU. Why buy or have two systems if it can be done by one unit? Most people don’t need nitrous output but it has two stages. Most people don’t use fan control but MS has it. It may only be pointless to the individual that does not want it.

[aarc240]

I'd likely use just such a feature with a caveat or two.
First would be due regard to safety features such as no start with engine running.
Second, able to over ride the clutch disengaged when starting.
Easy with serial wiring start button to clutch switch to MS and a switch in parallel with the clutch switch.
Why you might ask. Simply that at times I rely on the starter to fire the car while moving it slightly such as on a loose slope or when bogged in sand.
As a feature, you bet, particularly if i/o can be across CAN.

[DaveEFI]

Sorry if I struck a nerve with some of you. This was just something I was asked if MS could do. I have seen some new cars using this. MS does quite a few things that are not really needed to be handled by the ECU. Why buy or have two systems if it can be done by one unit? Most people don’t need nitrous output but it has two stages. Most people don’t use fan control but MS has it. It may only be pointless to the individual that does not want it.

Those things tend just to use output ports on the MS. To control a starter, you'd need extra inputs too. IMHO, if you wanted such a feature, a stand alone unit would be a more sensible arrangement since there's not any reason I can think of for integrating to MS. It's more something that could be part of an alarm/immobiliser.

[aarc240]

Why would one want to duplicate the important stuff that the MS already manages?
eg:
detect engine running
air conditioner control
nitrous control
and there isn't any reason to use i/o on the MS, an external board (GPIO, IOx, TinyIOx etc) can do that over CAN.
For anyone wanting / needing something like this the necessity to add another board would be pretty trivial.
btw, at least one OEM agrees - our export market Chrysler PT Cruiser manages the starter this way with the PTC (Power Train Controller), it just has a key start position instead of a button.

[Matt Cramer]

One thing that would simplify this feature is that a lot of starter relays are already wired to lock out the starter if the transmission is in gear or the clutch is engaged.

[elaw]

Buy a remote-starter kit and velcro the remote to the dash?

There's actually something I did years ago I'm surprised more OEMs don't do. The car had a manual transmission but had provisions for a starter relay to be used when the car had an automatic - coil + came from the "start" contact on the ignition switch, and coil - was grounded via the neutral-safety switch.

I installed a relay, but connected coil - to the "light" terminal on the alternator. When the engine wasn't running that terminal provided a ground that would allow the relay to energize and the starter to run. But if the engine was running, the terminal would sit at +12 volts and prevent the relay from energizing and thus the starter from running.

[jsmcortina]

One thing that would simplify this feature is that a lot of starter relays are already wired to lock out the starter if the transmission is in gear or the clutch is engaged.

The clutch switch might depend on the market, I think it is a USA specific feature?

James

[DaveEFI]

At least some in the UK have been infected by the nanny state too.

[Matt Cramer]

At least some in the UK have been infected by the nanny state too.

Neutral safety switches have been around since the 1960s here.

[aarc240]

Everywhere has the auto neutral safety switch and has had as long as USA.
Most countries didn't have the clutch switch on 'common' cars and neither did American cars until relatively recently, eg neither a '69 nor '71 Pontiac GTO nor a '85 Jeep that I owned previously had such a clutch switch (and having converted all three to RHD myself I knew the wiring intimately).
The clutch switch became a common feature when electronic cruise controls started to be a factory option.

I'd prefer the MS3 to monitor the push button (via CAN) and activate the starter after ensuring all MS controlled ancillaries are off.
Let's face it, a start pushbutton isn't exactly a high priority item for MS to monitor so there's no reason to use an input on the MS itself, nor is there any reason to do more than skip over the start sequence code if the engine is running.

Sure, it's entirely feasible to do it all externally.
Using the alternator as elaw did is a clever trick, add some normally closed relays in places like air con compressor clutch power, nitrous power, a normally open relay in the starter solenoid switched wire plus a bunch of wire to reach all the required places. Oh, and the clutch switch or auto trans switch and start push button .
What does that achieve that software and existing hardware can't in a lot tidier and more professional manner??

[750essess]

Wire up a RFID receiver. Walk up with key fob in pocket to turn on car/ bike. Pull out your phone with msdroid etc or a specific app to start/stop car. Is it necessary? No. Is it cool? Yes. Also would allow behavior like some bikes have where in you just tap start button and starter motor is stopped automatically when motor is running ( also not necessary but also cool

[racingmini_mtl]

An RFID only has a range of a few inches. You would need some other type of wireless connection to do what you want. With an RFID, you need to swipe it by the receiver.

Jean

[Turbo nut]

I was thinking it may be fairly easy (may not be I’m not a code writer) to have a momentary pushbutton switch connected to an input. When the switch was pushed it would trigger an output to a starter relay. This output would be active for X amount of time or until X rpm is reached. It would also be nice that output be cancelled if pushed again. I’m all for leaving safety switches in place. I’m not interested in remote start. Any input from code writers on this? Thanks Tom.

[kjones6039]

And lots of liability attached, I would think..........

Ken