Factory tach q's

[NYCEGUY01]

On a factory tach equipped truck where is the tach getting its signal from.

I want to eliminate the computer on this project truck. I allready have the transmission and voltage reg stuff figured out but kinda want to keep the stock tach working.

Anyone ???

[PToombs]

The front balancer. The sensor wire goes down the front of the head, there is a plug there that gets corroded too.

[NYCEGUY01]

But does the tach get its signal from the sensor directly or from the pcm that gets a signal from the crank sensor ???

I want to eliminate the pcm and need to know if it will still work without it.

[cummins king]

you could always put a mehanical guage in at the turbo line

[PToombs]

It comes from the PCM, sorry! I don't know if it will work without the PCM. Mine is wired from the alternator, works good, but you need the right tach.

[NYCEGUY01]

Damn.

Thats what I thought. I was hoping to leave the factory tach for a stock look in this truck. lol

[Philip]

If you can provide the tach a 5 volt signal it might work. The signal the tach recieves from the PCM is a 5 volt square wave signal. I think the PCM just reads the signal then sends it to the tach with no conversion of any type.