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McRat
September 7th, 2007, 11:27 AM
If 0 PSI = 7 ohms and 120 PSI = 160 ohms, how do I read that in using EFILive?

Redline Motorsports
September 7th, 2007, 01:07 PM
I think you need to somehow get this converted to a voltage reading. Can you find a Autometer pressure sender that works from 0-5 volts? That would be key as FS works in those voltage ranges.

Howard

joecar
September 7th, 2007, 02:35 PM
As Howard said, can you translate those values to 0-5 volts...?

McRat
September 7th, 2007, 03:31 PM
I know there is a way to turn ohms into volts, but electricity and I have a mutual non-aggression pact.

I agree that I will not screw with it, and it agrees not to send me to the Burn Ward of the hospital again! :D

Basically the circuit that inside an ohmmeter will do it, but I do not know how to look it up.

I went to Radio Shack and they said use a resistor. Nope. Even at 20,000 ohms, the voltage stayed at 12v regardless of what the pressure was.

I would like to use these $25 VDO pressure senders that go 0-150 PSI, but they are only Ohm based.

McRat
September 7th, 2007, 09:35 PM
OK, I think I figured it out.

Ira
September 8th, 2007, 03:39 AM
A 300 ohm resistor to 12V and one side of the sensor, the other side of the sensor to ground and connect the middle to EFIlive should do it.

Ira

Redline Motorsports
September 8th, 2007, 10:36 AM
Post results. Good info.

Howard