Powerlog Alcohol question

michael evans

Well-Known Member
Joined
Feb 27, 2008
I am getting parts together to log the Alcohol system.

Do I need to install a 330 ohm resistor the wire leading to the sensor that has 12 volts to knock it down to 4 volts or ?
 
I'm depends on what transducer you are using but for the most part the sensors are 5VDC . I actually am in the process of doing some wiring and made this board to supply my Back pressure sensor, fuel, and coolant pressure sensors with a 5 VDC power supply . I'm using a transformer to step the 12VDC down to 5 VDC .
IMG_7978.JPG
 
There is three different ways to reduce the voltage (12 volts) to five. 4.959 volts is really what I need, Just wondered if I needed to do it before the transducer or after. Seems like before would be better.

After redoing the math and finding the Powerloger only needs 5 milliamps, I need a 1410 Ohm resistor to get the voltage the easy way.

Is 5 milliamps correct ?
 
There is three different ways to reduce the voltage (12 volts) to five. 4.959 volts is really what I need, Just wondered if I needed to do it before the transducer or after. Seems like before would be better.

After redoing the math and finding the Powerloger only needs 5 milliamps, I need a 1410 Ohm resistor to get the voltage the easy way.

Is 5 milliamps correct ?
I'm a little lost with the terminology you guys are using. But I can offer this........

Do not supply 12 volts to a pressure transducer designed to work with 5 volts. Not even for a second. Not unless you have a few spare transducers sitting around the tool chest drawer.

Ask me how I know.

Find a 5 volt source in the factory wiring harness somewhere. There are a few places you can tap for 5 volts,
 
Ohm's law V = I x R .

I read it that the Powerloger only needs 5 milliamps for reading
I think your are looking into this way to deep . It needs a 0-5v signal. So no resistors or anything like that . You give the sensor 5vDC. Which u can pull off the TPS then the signal wire from the transducer will go to the input block of the power logger . So then the powerlogger can be setup so when it see 0.5 volts that = 0psi and when it sees 4.5 vdc = 100psi . That's a example for a 100psi transducer
 
I think your are looking into this way to deep . It needs a 0-5v signal. So no resistors or anything like that . You give the sensor 5vDC. Which u can pull off the TPS then the signal wire from the transducer will go to the input block of the power logger . So then the powerlogger can be setup so when it see 0.5 volts that = 0psi and when it sees 4.5 vdc = 100psi . That's a example for a 100psi transducer
Yea, this is what I guess I was saying. Seems like a lot of unnecessary calculation and components.

I don't have a powerlogger. I use XFI so I just used a 5 volt pin-out on the box's harness connection. But this is all you should need to do.
 
Yea, this is what I guess I was saying. Seems like a lot of unnecessary calculation and components.

I don't have a powerlogger. I use XFI so I just used a 5 volt pin-out on the box's harness connection. But this is all you should need to do.
Yea when I had one transducer I just tapped into my ECMs 5 volt supply. But now I have 4 pressure transducers and I didn't want to run all those off one supply . I bought a transformer to step down the voltage . It actually is dead on 5 volts un like my Ecm lol .
 
I see what you did and it makes perfect sense to me. How many leads can one pull off the same 5 volt wire that already basically loops around the wire harness to supply 5 volts to a bunch of factory sensors?

Fortunately, the XFI has a few spares for additional sensor add-ons. And when I run out, I figure, at some point I need to stop gathering information before my brain explodes!!!!! :wacky:
 
I think your are looking into this way to deep . It needs a 0-5v signal. So no resistors or anything like that . You give the sensor 5vDC. Which u can pull off the TPS then the signal wire from the transducer will go to the input block of the power logger . So then the powerlogger can be setup so when it see 0.5 volts that = 0psi and when it sees 4.5 vdc = 100psi . That's a example for a 100psi transducer

That would make things much easier. I just did not want to hurt anything
 
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