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 When is my engine running?

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pdadio

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Join date : 2012-05-07
Age : 62
Location : Fair Oaks, CA

PostSubject: When is my engine running?   Wed Jun 27, 2012 9:52 pm

This maybe a strange topic but I would like anyone's thoughts.

So my squareback starts via a relay that is controlled by a computer. I want my car to start with a momentary push of a button. That means that my computer has to 'sense' when my engine is running or not. In other words, I want the push of a button crank my engine over until it runs by itself. Here's the steps of the process:

1. Push the button once.
2. Computer turns on starter
3. Computer cranks the engine until the engine starts on it's own
4. Computer senses when the engine is 'on'
5. Computer turns off starter

I have an Acura TL that does this. I don't have to keep the key in the start position. It knows when the engine is running. I just turn the key 'on' just briefly.

One thought is to turn the starter on when the RPM of the engine is low while it is turning over and off when the RPM of the engine higher while running.

Another is to measure the output of the alternator. If the voltage is low, the engine is still cranking. If the voltage is normal, the engine is running.

Any ideas? The great thing about computer is that with the right inputs and outputs they can be programmed to do just about anything.
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TheAmazingDave



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Join date : 2012-05-02
Age : 34
Location : San Jose

PostSubject: Re: When is my engine running?   Wed Jun 27, 2012 9:58 pm

You'll need a programmable microcontroller. BASIC controllers are easy to get and easy to program, and they should have several analog inputs and outputs.

Program it so it activates an output when it receives an input. Another analog input can be connected to the points (or electronic ignition pickup, and the controller could be programmed to release the output when the second input reaches so many pulses per second.

Probably above 600 RPM or so.

Should be relatively easy if programming doesn't scare you.
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mikeinch

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Location : citrus heights

PostSubject: Re: When is my engine running?   Wed Jun 27, 2012 10:35 pm

Alternator output sounds simple enough, but you might run into problems should your alternator/generator go out. I have had to drive home on just a battery but it wouldnt work in your case. I would have to go with engine RPM. Funny thing is, I got into VW's because they are so simple.
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pdadio

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Age : 62
Location : Fair Oaks, CA

PostSubject: Re: When is my engine running?   Wed Jun 27, 2012 11:13 pm

yeah, I've got my VW microcontroller (Arduino) running already. I picked a VW to run off a computer just for the fact they are so simple.
Here's the car and and computer specs:

https://sites.google.com/site/my1970vwsquareback/

I was thinking of taking the RPM off the points and feeding that in to a microcontroller. Anyone tried that on a VW before?

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Mateo
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Age : 49
Location : North Auburn

PostSubject: Re: When is my engine running?   Wed Jun 27, 2012 11:16 pm

Sounds complicated...

Get your engine tuned correctly and then program your start button to turn the starter for two seconds.

That's what I would do. LOL.

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