How does a Tach work?

[h2odrx]

Ok
does the tach send a voltage to the dash? i was thinking of tapping in to it to maybe run a valve that will control say LP flow??
what do you think??

 

[highest_vision]

I don't know for sure, but just from handling those sensors I would think they produce a small AC voltage, relative to engine speed. Less small the more you increase engine speed. Probably under 1VAC. I imagine you can find a valve to work with this or a buffer to make this signal work with a valve you find. Even if the signal is DC voltage.
James

 

[highest_vision]

On 2nd thought, you could also stick a microswitch on the throttle linkage area, such that it will be actuated when you want. Either RPM or throttle, I am guessing you will want this under load circumstances and can set the microswitch to come on then.
Or not Don't know what you are after...
James

 

[h2odrx]

I was justb thinking..(dangerous i know) Zigg has the one with the micro switch i was thinking about some how using the tach to control a switch or something to allow LP to flow at different rates?

 

[highest_vision]

Well, depending on how you are at wiring and putting electronics to use, you can do this. Some people pay $800 for this but it might be more satisfying to do it yourself if you don't catch on fire!
You would need to sample the voltage produced by that sensor at various rpms and create a map to understand visually what you were looking at. Procure some flow control valves of various rates. Map out at what rpm you would like what amt of flow. Probably need a signal buffer. You would likely be able to do this without any computerization. There are multiple ways of controlling flow, you will have to decide on this. Still probably be best to have a microswitch for idle validation, just in case.
James

 

[h2odrx]

You would need to sample the voltage produced by that sensor at various rpms and create a map to understand visually what you were looking at. James

I was hoping there was already a given for this? i just was looking at the wiring diagram with only seeing what went where.

Still probably be best to have a microswitch for idle validation, just in case.
James

Good idea, kind of like a kill switch?

 

[highest_vision]

You could reasonably assume that the signal changes predictably, but with no idea of what it is at idle and at what rate it changes you will have to sample it. Especially at your intended cutoff/in points.

Good idea, kind of like a kill switch?

Kind of what I was thinking!!
James

 

[h2odrx]

my boss was a tv repair man... (people on ludes should not drive) oh wrong movie.... and does some wild stuff with electronics so when and if i get the truck back together i might just have to hook something up?