Number of Pulses per Rev in Tach Signal

Dmitriy

#1 28 Oct 2002, 21:09 ◈ 2012-09-19

I want to do a project for setting up my own rpm guage with the use of a basic stamp processor and a chep ol LED screen.
Does anyone know the number of pulses in the tachh wire for to be able to read this and work properly?

90wagon

#2 28 Oct 2002, 22:03 ◈ 2012-09-19

Re: Number of Pulses per Rev in Tach Signal

I'm assuming it's the same as anyone else's tach output, after all, aftermarket tachs do work with the honda ignition system...

Dmitriy

#3 28 Oct 2002, 23:37 ◈ 2012-09-19

Re: Number of Pulses per Rev in Tach Signal

And that would be?

I know its something between 3 and 4 because i believe 4 was the one that showed the closest RPM's to my tach when installing my security system.

What is the number of pulses per crank revolution in the tach signal?

blundar

#4 28 Oct 2002, 23:40 ◈ 2012-09-19

Re: Number of Pulses per Rev in Tach Signal

I thought it was 4...

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Dmitriy

#5 28 Oct 2002, 23:45 ◈ 2012-09-19

Re: Number of Pulses per Rev in Tach Signal

Anyone know the answer for sure or where I can find out?

doc

#6 29 Oct 2002, 00:44 ◈ 2012-09-19

Re: Number of Pulses per Rev in Tach Signal

RPM = 2 pulses per Revolution (on the Ingition Output Wire)

I measured it with a scope a while ago, while i was building a simple vtec-controller.

Speed = 4 pules per Revolution (wheel)

Dmitriy

#7 29 Oct 2002, 03:06 ◈ 2012-09-19

Re: Number of Pulses per Rev in Tach Signal

What about the lue tach wire that goes to behind the guage cluster?
is that also 2? or is it 4?

Darksmiles

#8 31 Oct 2002, 05:14 ◈ 2012-09-19

Re: Number of Pulses per Rev in Tach Signal

Ok here is the answer straight out of the Honda factory service manual.

"Indicates 100 rpm at 200 pulses per minute of the ICM"

Soooooo using my awesome math skills it dictates that you will have two pulses every minute for every RPM. i.e. 3000RPM = 6000 pulses in a minute or 100 pulses per second.
This holds true for the blue tach wire as well as the ICM signal which the ECU uses to create RPM.

Evan

#9 31 Oct 2002, 06:08 ◈ 2012-09-19

Re: Number of Pulses per Rev in Tach Signal

ahhh... i found a maths buddy!

l'm looking forward to enthrauling discussions about Fermats Last theorem!

Darksmiles

#10 31 Oct 2002, 14:16 ◈ 2012-09-19

Re: Number of Pulses per Rev in Tach Signal

lol.

I was actually being a little sarcastic. My math skills are pretty good but I'm no mathematician. I took a few math courses (calc and alg.) in uni but I'm a scientist and we all know that us scientists LOVE our calculators.

And ewwwwww Fermat!!

Evan L

#11 31 Oct 2002, 15:14 ◈ 2012-09-19

Re: Number of Pulses per Rev in Tach Signal

i understood the sarcasm and i wasnt being serious either!

i too love the calculator, @!#$, i cant even remember my times tables!

Darksmiles

#12 31 Oct 2002, 16:33 ◈ 2012-09-19

Re: Number of Pulses per Rev in Tach Signal

Haha me too!!

I get slower than average once over 12x lol!

Dmitriy

#13 31 Oct 2002, 20:15 ◈ 2012-09-19

Re: Number of Pulses per Rev in Tach Signal

thanks darksmiles....

anything under a hundred is easy to multiply since you just seperate the numbers and then add them

Andy Locoweed

#14 01 Nov 2002, 00:02 ◈ 2012-09-19

Re: Number of Pulses per Rev in Tach Signal

No prob. Glad I could help.

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