circuit to shorten ignition signal?

Printed From: the12volt.com
Forum Name: Car Security and Convenience
Forum Discription: Car Alarms, Keyless Entries, Remote Starters, Immobilizer Bypasses, Sensors, Door Locks, Window Modules, Heated Mirrors, Heated Seats, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=107455
Printed Date: May 13, 2025 at 3:46 PM

Topic: circuit to shorten ignition signal?

Posted By: kwchan
Subject: circuit to shorten ignition signal?
Date Posted: September 15, 2008 at 8:10 AM

My remote starter is time based, and the ignition signal is too long for my starter motor.

When I use remote start, I can hear that the starter motor still continue to run for 1 sec after engine is cranked.

I am not sure if it is healthy for the starter motor in a long run. Since the "cranking" time cannot be adjusted nor there is any tacho detection signal, I will need to add a circuit to shorten the ignition signal.

What is the easiest way to shorten the ignition signal?

thanks in advance!

Replies:

Posted By: i am an idiot
Date Posted: September 15, 2008 at 9:33 AM

Constant to Momentary Output

The capacitor allows the coil of the relay to be energized until the capacitor stores a charge, thus de-energizing the coil. The resistor bleeds off the charge of the capacitor when positive voltage is removed from the other side of the coil. You can increase the output time by simply changing the value of the capacitor. This one will give you about a 1/2 second output.
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Posted By: howie ll
Date Posted: September 15, 2008 at 10:37 AM

Technically you need to shorten starter crank time and as far as I know all R/S units have this facility OR an anti-grind facility. the above will also work just as well on your starter output lead from the remote.

Posted By: kwchan
Date Posted: September 15, 2008 at 12:03 PM

thanks for the quick reply, i have checked the remote starter unit and there is no way to adjust the crank time.

I know there are higher end model that can detect the rpm and cut off the cranking as soon as the engine start. too bad mine doesnt have this feature too.

Posted By: KarTuneMan
Date Posted: September 15, 2008 at 12:56 PM

What's the year make and model?

Are you using a good tach signal?

What type of remote starter?

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Posted By: kwchan
Date Posted: September 16, 2008 at 6:06 AM

nothing to do with the car, it is a china-made 2-way alarm with remote start function. However, the remote start function is a bit crippled as the crank time cannot be adjust. Neither there is any sensor to detect the RPM of the engine.