Time Delay for Remote Start Tach Wire

Ok, here is the problem. I need a wire that gives 12v+ to the sensor wire when the motor has been started, otherwise the alarm will keep cranking. I have tried just using an accessory or an Ignition wire, but the alarm wants 12v+ WHILE it is cranking, not after. The remote start will work if I give the sensor wire 12v+ after I hear it start running (like if I were turning the key I would stop turning) so I'm sure it is not the main unit.
Now,I have found the tach wire, but it only gives .75v+ when I have the motor cranking - not yet running. When the motor is running it still gives .75v+ and will increase as rpms increase.   
My thought is I should hook up a time delayed relay such as here (about 4 seconds, enough for the engine to start running) either to A) this tach wire that I found or B) the actual starter wire that the remote start uses.
If the car does not start, I could always start it again, it really does not matter to me.
Please give me some insight if you see another way of getting 12v to the sensor wire or if you have a diagram for me to use on hooking up the relay. Thanks for any help and if I'm not clear enough, please ask more questions.

Edit: The car is a 1995 Dodge Avenger - if this helps anyone. I'm just having a tough time identifying a wire that has 12v+ after the engine is running - if anyone can find such a wire, my above post is pretty much worthless.

Don't know what you are installing, but if you need 12 Volts WHILE it Cranks....Use CONSTANT wire.............

You have contradicted yourself by saying it needs 12Volts AFTER it is Running & 12 Volts ONLY while it is Cranking

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MO

Don't Learn from Others Mistakes
You Might Be the One That Knows.

Nope, I need 12V after the motor has started, but is still cranking. Its the sensor wire for the remote start

bpoppe4 wrote:

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Nope, I need 12V after the motor has started, but is still cranking. Its the sensor wire for the remote start

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That would still be the CONSTANT 12 Volt wire

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MO

Don't Learn from Others Mistakes
You Might Be the One That Knows.

If I connect it to a CONSTANT 12v the remote start will not even crank, i.e. it thinks its already started.

Update: Tach wire puts out .75v when started, .2 when cranking and not started - how do I hook up a relay to trigger the 12v?

Sounds like a CarVox R / S

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MO

Don't Learn from Others Mistakes
You Might Be the One That Knows.

Ok, here is what I need - when you turn the key, the engine is cranking. While the engine is cranking, at some point it will start (the point at which you would let off the key, somewhere around 3-4 seconds). In order for the remote start to work, it needs 12v at that instant - the point at which the engine starts running.

Disagree on the Method you are needing.............

SPDT Relay:
PIN 30 = "Sensor" wire from R /S
PIN 87a = Starter Wire ( Splice into )
PIN 87 = 12 Volt Constant
PIN 86 = 12 Volt Constant
PIN 85 = Status wire that Powers Accessories from R / S ( so that it comes on AFTER cranking )

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MO

Don't Learn from Others Mistakes
You Might Be the One That Knows.