Engine Running +ve Signal?

[IAmOrion]

Unlike me to be unsure about electrical stuff here ha - but, does any know where I can get a +ve Engine Running Signal?
In other words, a +12v wire that is ONLY +12v when the engine is running? Anyone know the location of the Oil Pump +ve? Or perhaps there's a +ve line elsewhere inside the car?

Just to clarify - I do NOT want a +12v Permanent feed or a +12v Ignition Feed... I specifically need a feed that is only 12v with engine running.

MTIA

 

[smorris_12]

That's going to be tricky as i expect the car will rely on kbus signalling for any systems that want to know if the engine's running.

If it was me, I'd probably build a simple voltage comparator and look for V+ being above 13v.

Or use the oil pressure switch line (which probably drags the line low and would need inverting)

Or a latching relay switched from stage III ignition and kept latched by stage II ignition power. Although that would give a false positive if the car fails to start. Depends on the application as to whether that matters (hint: what are you up to??!)

 

[bigwinn]

What about using one of the alternator output cables?

I can’t think of much else?

 

[IAmOrion]

What about using one of the alternator output cables?
I can’t think of much else?

Whilst I've not yet tested myself, I'm lead to believe (for the E86/E86 at least) the Alternator doesn't have such an output like the older cars used to have. (Known as a D+ wire or something) Instead, they have a bsd feed (bit serial data) which is useless for my needs.

 

[bigwinn]

What about using one of the alternator output cables?
I can’t think of much else?

Whilst I've not yet tested myself, I'm lead to believe (for the E86/E86 at least) the Alternator doesn't have such an output like the older cars used to have. (Known as a D+ wire or something) Instead, they have a bsd feed (bit serial data) which is useless for my needs.

That’s the one

Ah ok never mind

I’ll think on

 

[IAmOrion]

That's going to be tricky as i expect the car will rely on kbus signalling for any systems that want to know if the engine's running.

If it was me, I'd probably build a simple voltage comparator and look for V+ being above 13v.

Or use the oil pressure switch line (which probably drags the line low and would need inverting)

Or a latching relay switched from stage III ignition and kept latched by stage II ignition power. Although that would give a false positive if the car fails to start. Depends on the application as to whether that matters (hint: what are you up to??!)

Somehow I missed this post!! I got alerted to bigwinns response but not yours. Odd!

Anyways, I’m playing with a remote start/PKE system. I have to stress “playing” as I don’t know if I’ll keep it permanently I’m just trying stuff out. It needs a +ve signal to “confirm” the engine is running, otherwise, when using remote start, it will keep trying to start the engine despite it being started already.

I’ve actually modified my sport button mod PCB and doing exactly that - using a voltage divider. 12v ish = normal, 13.5v ish = charging (eg via an independent charger) and >14 = running. My sport button mod already used an optocoupler so should be able to use it as the trigger. Eg, attiny85 (think Arduino) will trigger the optocoupler if the voltage is >14v which, when triggered, will output 12v. Should work for my needs and easier than messing with kbus stuff (although fwiw I already have my own kbus/can bus circuit in use - so I guess I’m kinda being lazy )

 

[smorris_12]

You sound like you're trying to get out of pulling something apart you've already put in place! (Know the feeling well!)

Other alternatives would be to integrate the pulses from the crank/cam sensor; build a sound operated switch or have a small child permanently on standby to press a button when the engine starts!

 

[IAmOrion]

You sound like you're trying to get out of pulling something apart you've already put in place! (Know the feeling well!)

Other alternatives would be to integrate the pulses from the crank/cam sensor; build a sound operated switch or have a small child permanently on standby to press a button when the engine starts!

Yeah - sometime ago I did an instrument cluster conversion and replaced my clocks with a Haltech IC7 Digital Dash. As part of the process (and actually as part of a diff project I was playing with regarding kbus stuff), I needed to design a KBus + CANBus shield I could use with an Arduino. As a part of that previous kbus project, I implement a secondary stacked shield that consisted of 4 relays - the idea at the time being I could repurpose unused MFSW Button such as the phone call button to trigger a relay instead. Fast forward to the Haltech IC7, and I used that setup I made to convert the required CANBus and KBus data is a way the Haltech IC7 could use. I never utilised the relays at the time, and now it's like a year later and it's buried deep behind the dash I really *CANNOT* be arsed spending hours to dig it out and add some new code to give me a +12v signal when running! :lol:

I was hoping there'd be a simple solution like those of older cars when "D+" was still a thing - a simple wire that was +ve when engine running. Of course, newer (is 2000+ still "newer" these days) did away with that simplistic stuff.

So fast forward to this weekend and as I mentioned, I went with my voltage divider option and a little ATTiny85 circuit. I can fine tune the code and do different things depending on voltage - eg 12v -13v ignition on do xyz1, 13v-14v battery being charged do xyz2, >14.1v Engine is running do xyz3 ... so I guess I've now resolved this the harder way but it all worked out in the end

Thanks again for your input

 

[markplant]

Use to love having remote start on a car

 

[enuff_zed]

Use to love having remote start on a car

I'd bugger it up, due to my winter habit of leaving the car in gear with the handbrake off.
I'd be the only one with a remote stall set up.

 

[IAmOrion]

I'd bugger it up, due to my winter habit of leaving the car in gear with the handbrake off.
I'd be the only one with a remote stall set up.

Or a remote bunny hopper! You get to watch and panic as the car keeps inching forward as it tries to start ha

 

[enuff_zed]

I'd bugger it up, due to my winter habit of leaving the car in gear with the handbrake off.
I'd be the only one with a remote stall set up.

Or a remote bunny hopper! You get to watch and panic as the car keeps inching forward as it tries to start ha

Ideal if you break down on a level crossing. You get to safety, then coax the car over.

 

[IAmOrion]

Ideal if you break down on a level crossing. You get to safety, then coax the car over.

Result!!

I'm actually a little scarred with remote starts - it's like something out of a bad comedy film... Was about 24 years ago now, I had a remote start system fitted on a Ford Probe (what a choice of vehicle I know!). One morning it was like -5, so cold, ice everywhere. I had the bright idea to remote start the car so it'd defrost and be nice and warm when I'm ready to leave for work. Queue the sheer panic, as, because it was so cold, I'd left it in gear with handbrake off so the handbrake didn't freeze on... car starts bunny hopping up the road, can't cancel the remote start from the remote (stupid design eh! Nice one clifford ) so run out to car - but because it was so cold the door was frozen shut, so I'm frantically trying to get into the car - but alas, it bunny hopped far enough to smack into another car whereby the door then finally opened and I could get handbrake on and press foot brake to "cancel" the start attempt. It smashed the front light of the other persons car (the cars were parked facing each other)

 

[N4LLY]

Love it

 

[smorris_12]

I barely trust myself to start a car when I'm in it!!

 

[IAmOrion]

For anyone interested, I made my own circuit with an ATTiny85 to give me a trigger signal when engine is running









OLED Display screen and NeoPixel is optional - mainly used for testing. OLED shows voltage, charging status and running status. NeoPixel is RED for “normal” state, GREEN for charging state, and BLUE for running state

I've actually already tweaked the design but don't have the PCB in my hand yet for a photo. The revised version simply adds a Slide Switch so that you can select the output signal. So you choose for it to active a +ve output signal, or a -ve (gnd) output signal. I did this as some different kits such as push button start kits etc can often require different signals. Some want a -ve (gnd) signal as the trigger, so want a +ve signal as the trigger, so obv being able to select the output signal is a more universal design. The one pictured outputs a +ve signal only as for my use case I needed a +ve trigger.

 

[smorris_12]

Ooh, I gotta get me one of those displays. Dunno what for but I'll find something!

Nice little project you've got there!

 

[IAmOrion]

Ooh, I gotta get me one of those displays. Dunno what for but I'll find something!

Nice little project you've got there!

Thanks

The little 0.96" 128x32 I2C OLEDs are great for things like this! Cheap too