[Catalyst_delhi]

Originally Posted by RM2488

It is impossible to double crank on my Ikon... mainly because you cannot physically turn the key after a crank attempt, even if it does not start the engine.

This is mechanically done with a ratchet setup in the cylinder. It is irritating sometimes as you have to take the key out to start again.

[ghpk]

I am all in for this D.I.Y as a Santro Owner and a big D.I.Y types.

Let me dig some mud off my mind and get back on this, I would prefer a timer circuit to prevent a double crank after initial crank this would certainly help engine start smoothly then cut the chances of re-crank and then resets back to ready state once the key is not in IGN position.

[Mr.Boss]

Making a PAUSE on this project.
My friend taken back the car as he is traveling to his hometown for Diwali. Hope to continue after a week or two.

[vijaycool]

Palio has this mechanism but basically its a design with the key barrel assembly. The lock will engage while turning the key and stays in locked position so you cant crank again. Turning to OFF position will reset the lock so you can crank on more time. Pretty useful feature.

[vikram_d]

Originally Posted by vijaycool

Palio has this mechanism but basically its a design with the key barrel assembly. The lock will engage while turning the key and stays in locked position so you cant crank again. Turning to OFF position will reset the lock so you can crank on more time. Pretty useful feature.

Most Fords also have this feature. The Mondeo, Fiesta Classic and the new Fiesta have it for sure. Not sure about the other ones.

[Sutripta]

Originally Posted by audioholic

^^ Sir how can that be used to prevent a double crank? Could you please explain?
Taking the logic of fuel pump being cutoff on impact, the default state will be logic 1. That if we invert, we will have logic 0 signal until there is an impact and only then will it turn to logic 1. That will help prevent cranking when there is an impact from what I can think of.

Pump powered => Engine running.
Engine running => Disable starter relay.

Exception to be handled - During initial startup, fuel feed pump is running. This has to be handled. Use a timer.

In pre ECU days, the two common points checked were alternator output, and oil pressure. A crash was not detected by means of sensors, but just by assuming that the engine has stopped running while ignition was still on.

Regards
Sutripta

[im_srini]

Originally Posted by Sutripta

In pre ECU days, the two common points checked were alternator output, and oil pressure.

Hi Sutripta, good stuff... Can we then use the oil pressure switch output & ignition switch output (i.e. ignition is on & oil pressure switch is off), as an indicator that the engine's running ?

[ilangop]

Originally Posted by im_srini

Hi Sutripta, good stuff... Can we then use the oil pressure switch output & ignition switch output (i.e. ignition is on & oil pressure switch is off), as an indicator that the engine's running ?

Better to take the Alternator WL output or Fuel pump signal, because in most vehicles the oil pressure switch cuts off even while the engine is being cranked a few turns. You can easily percieve this as the oil warning lamp turns off even before the engine fires and sustains by itself.

I could foresee one issue with tapping the fuel pump signal for preventing double cranking. Some delay circuitry has to be provided because, for the first crank one has to again wait for a couple of seconds till the fuel pump primes and turns off. Without the delay, as soon as the engine is cranked the fuel pump again turns on and would disengage the cranking mechanism. Hence there is a need to delay the deactivation of crank signal if the fuel pump signal is used.

[Sutripta]

Originally Posted by im_srini

Hi Sutripta, good stuff... Can we then use the oil pressure switch output & ignition switch output (i.e. ignition is on & oil pressure switch is off), as an indicator that the engine's running ?

I think just presence of oil pressure is sufficient to say engine is turning over!

Originally Posted by ilangop

Better to take the Alternator WL output or Fuel pump signal, because in most vehicles the oil pressure switch cuts off even while the engine is being cranked a few turns.
.....
Without the delay, as soon as the engine is cranked the fuel pump again turns on and would disengage the cranking mechanism. Hence there is a need to delay the deactivation of crank signal if the fuel pump signal is used.

Starting has to be handled separately. (Normally done with a timer, as mentioned). Because one has to distinguish between an engine turning over on its own power, and being made to turn over.

A timer is also usually used to turn on the fuel pump on first ign power up to prime the system. This signal, if accessible, can be used to advantage.

Regards
Sutripta