99SS-T

iTrader: (5)

I am hookin my meth kit up and i was wondering if anyone can tell me which wire i can get 5 volts from? I have been told that the TPS and the MAF both run off 5 volts but the same people dont know which wire is the feed. I knoa i can go out and buy a volt meter but aitn it easier to have knowledgable people just tell me? Thanks


John

disassembled

iTrader: (3)

I would not tap off of a sensor for a voltage supply. To me, doing what you want to do would cause headaches down the line either from blowing up the PCM or screwing with the sensor outputs thusly, screwing up how your car operates. Why not buy a voltage regulator and run it straight off the fuse block? I tapped my 12v supply from the ign fuse block so i only get power when the key is in run or start. I am not positive of the makeup of the components for such a circuit but it may be something as simple as a ceramic resistor coming off of the +. Check radio shack or partsexpress.com Those are the only place off the top of my head that would be able to supply the parts for what you want to do. I am sure if we have some electronic gurus in here they will be able to help more.

Greg

Nickn20

I beleive a zener diode would be able to step down voltage for you, there are formulas for what one to use though, and what resistors, why does the kit operate off of 5 volts?

99SS-T

iTrader: (5)

The kit itself dont operate off 5volts but the MAP sensor that it utilizes to know how much to blow in does. I checked radio shack and they dont have any and couldnt find any in thier part books and i dont feep like runnin around trying to find one. Thanks


John

barito48

This would give you regulation + isolate Internal PCM.

MrDude_1

iTrader: (4)

what barito48 just posted would work...

what you need is a 5 volt regulator..

now, this regulator will need a heatsink. so get a small one, or strap it to a piece of scrap alum.

if it was for my car, id also stick a couple capacitors in to smooth out the rather noisy electrical environment.. and a diode incase i become a idiot one day and hook it up backwards (it happens to the best of us.. lol)


attached is a pic i cropped out of some gadget i made...

J5 is the connector to goto the car... or use some wires or something.

the cap labled C8 in the pic takes any waves or changes in voltage and attempts to smooth them out some... i used digikey part # 399-1818-1-ND... 1000pF Ceramic cap

the diode D1 keeps you from frying your project if you hook it up backwards.. leave it off if you want, but id keep it.

U3 is the regulator... its just like the pic above.. power in one pin, ground on another and a regulated 5v comes out the remaining pin.
of course, it generates alot of heat changing 11-14.5v to 5.... so put a heatsink on it.

jimmyblue

iTrader: (11)

I would also recommend not touching the PCM +5V
reference lines.

What I think you want, is a good ole 7805 3-terminal
voltage regulator. National makes 'em as do others.
The one shown above is similar and fine too. They vary
in output current, presence of current limiting (a good
thing) and so on. National's web site has selection
guides if you want to dig deeper. The 7805 has not
ever done me wrong and is pretty sturdy & simple.
Get one in a TO-220 case and you can find heat sink
stuff (not to mention, used to find the regulator too)
at Radio Shack, properly heat-sunk they can source
an amp (I recall) though if you're getting close maybe
another, higher-power-capability regulator might be a
better idea. Linears are pretty simple to use and I don't
think you care much about efficiency.