I need to figure out how to log fuel pressure...with an electronic linear 0-5V signal. Of course the easiest way would be to use a linear 0-5V pressure sender but I can't seem to find one.

Anyone know of one? All I found was some aircraft control box that excepts one, but couldn't find the sender?!!? (page 9 http://www.mglavionics.co.za/Docs/TP2.pdf)

If anyone has any other ideas...please share.

 

Are you working with 0-5 psi or fuel injection pressures? If its fuel injected I bought my dataq system throughhttp://www.motorsports-exchange.com You'll see the "Aim dataq store" button. You can find sensors there for most things that operate on 0-5V. I use the 0-5bar(75lbs) sensor on my car.

 

You could connect up an oil pressure sender. Most are 1/4NPT with a negative coefficient for resistance. (Very high or infinite resistance at 0psi, resistance falls as pressure builds) Any circuit that can deal with a one-wire or two-wire coolant temperature sender should be able to aqequately deal with an oil pressure sender.

You'd need to calibrate it, of course, but that should really be No Big Deal.

 

thanks for the input...this is a fuel injected system (looking for 0~80psi). I need to find one that has a referene 5V input, more or less like a TPS signal.

The data log system I'm using has a "user input" for 0-5V so I figured this would be the easiest way to log fuel pressure.

 

Most of the newer Autometer gauges got a seperate output for datalogging.

 

Did you ever find an appropriate 5V pressure sensor? I have been looking for the same thing. Currently, I am considering one of the Dakota Digital resistive pressure sensors. It will require a 5 volt regulator and a series resistance. Considering the sensor only costs ~$23 that isn't too bad. Still haven't been able to locate a pressure vs resistance graph or equation for it though. I'll probably have to characterize it manually with a conventional guage.

 

The oil pressure sender is a great idea. Yes I know its 12V but there is a sollution. An opamp is the best way scale the voltage for a 0-5V signal but if you just want a simple and fast sollution go to radio shack and get some resistors.
http://en.wikipedia.org/wiki/Voltage_divider
Use a bike pump and T in na seperate good or better yet calibrated gauge and plot a Volt-psi graph for reference. It may not be that accurate in terms of actual pressure but for fuel pressure change is all you are looking for I am assuming.

 

http://www.motorsports-exchange.com/eStore2.htm#Sensors

the VDO pressure sensor they have listed has a 10bar option. 0-400mv output

 

Summit sells the sender for Autometer gauges that is 0-5v output. Check out the Innovate website too (makers of WB 02) for other options of logging fuel pressures and EGT.

Tony

 

I'm using this http://www.imakenews.com/sunxramco/e...e000025221.cfm
and logging the voltage on the Zeitronix ZT-2 using the 0-5V user input. It logs as a voltage but I export the Zeitronix datalog to an Excel file which translates the voltage to fuel pressure via a formula.

Works great so far but the Sunx unit is not cheap. Costs around $200 for the head unit (controller), separate sensor and wiring. BTW This is also a digital pressure switch with 2 independent setpoints. (See documentation)

I'm actually use a similar digital pressure switch/sensor to turn on my water injection pump and injector.

 

That is a pretty cool system. It appears that that the bare sensor can be used without the controller (1-5V analog output). I expect this would be much cheaper.

Where can you buy this stuff? It looks like it is normally used in microchip manufacturing.

 

This is exactly what I need...as I'm using Zeitronix as well.

except I don't want to spend $200 to log pressure...I want a 0-5V sender. Not a controller, etc that can monitor 0.001psi difference in 0.001 seconds.

 

I just got off the phone with Dakota Digital and I am a little dissapointed with them. I called to get the specifications for their 0-75psi pressure sender. The guy said they "do not offer that information". They consider a primitive resistive pressure sensor as proprietary? That is ridiculous!

I'll just characterize it myself.

 

Honeywell sells automotive-grade pressure sensors, typically used to measure engine oil and hydraulic pressure in off-road equipment. There was an ebay seller a while back unloading piles of them for a few dollars each. The units being sold required a 5v regulated supply (TPS circuit in my case), and provide a linear 0.5-4.5v output, 0-100psi range. Check out part number ML100PS2PC or ST100PG2BPCF on the honeywell site (http://tinyurl.com/jxmjf). I'm using one of these to datalog fuel pressure in my, and it works well. Sorry, but I don't know about pricing/availability.

 

SPA uses a 0-5V pressure sender per the owner's manual. I haven't tried to log it yet so I don't know if it is linear output.

Jack

 

Yes, those sensors are typically used in the microchip manufacturing industries for automation purposes. It is powered by 24 or 12 VDC so it is perfect for automotive applications. The sensor costs about $90-100. You will have the get the wiring details on the sensor if you want to get the reading directly from it. I can't recall where I got it from right now but check the net for any Sunx dealer. I think Keyence makes a similar sensor head which functions the same so do a google search for that as well.

 

Fuel pressure logging is working! I am pretty happy since the total cost was about $40!

$24 Dakota Digital 10-2 pressure sensor (really just a VDO sensor)
$6 Pressure Gauge Fitting
$1 180 ohm resistor
$2 5 Volt linear regulator

Before installing it in your car, it is best to characterize the pressure sensor using a gauge and a voltmeter. This will compensate for any variations in the sensor and signal conversion. A linear equation will work, but a quadratic is a better fit.

 

The sensor you are using is that setup for oil or fuel pressure? Also where did you purchase the sensor. I can only find the oil pressure sensors. Does it matter if you use fuel instead?

 

The sensor is intended for fuel. I bought this one from www.summitracing.com.

 

good work