Fuel Rail Pressure Voltage Output

Rogue Diesel

Rogue Diesel

New member
Does anyone know the fuel rail transducer voltage to psi out put for a 6.7 common rail?

The rail pressure sending unit is 5Vdc and it measures linear. So, output would be the following:

Example:

.05v = 0PSI or .05v = 0Mps

0 psi = 0.5v
5800 psi = 1.4v (idle)
26700 psi = 4.56v (max reading on transducer before saturation)

(The information above is the output for a 5.9 common rail).


I know that the sensor transducer is essential just producing volts and when you install a gauge, it converts it into PSI.

Thanks guys!
 
Assuming it IS linear (there will always be slight variations between units), that should be pretty easily calculated in an excel table, with a spread of 4.06V and 26700 psi. However, the resolution may be a bit "generalized. Divide 4.06 by 26700, multiply by 5800 and add .5 (your output voltage floor) and you get 1.353188V (to prove your calculation). That's pretty close to your 1.4V statement. You could possibly hook up an actual calibrated pressure gauge, and make a table of voltage measurements to see if the difference (between 1.35 and 1.4) was a constant and if so apply that to your table globally to refine it. But if you ever changed the transducer, you'd have to do it all over again.
 
What's the end goal here? All of the rail sensors should read linear. The 6.7L rail sensors should read 200mpa
 
The scaling map from on 05:
Volts Bar
0.50 0.00
1.50 44.99
2.50 89.99
3.50 134.98
4.50 180.02

On an 08 - you said 6.7 but not what year - the map is much simpler:
Volts Bar
0.00 0.00
0.25 0.00
0.50 0.00
4.50 199.98
5.00 199.98



The voltage values between those listed are interpolated to produce the bar that the ecm sees. As you can see on the 6.7 the bar is the result of the interpolation of the scale between 0.00 and 199.98 in a voltage range of 0.50 and 4.50.

Hope this helps.

Paul
 
JWhite said:
What's the end goal here? All of the rail sensors should read linear. The 6.7L rail sensors should read 200mpa
Click to expand...

I have a buddy who is a mechanical engineer and he is building me another rail pressure gauge for my 2010, 6.7. So, what he needs to know is the max PSI rail pressure of a 6.7 and the idle rail pressure of a 6.7. This is how he will set the parameters on the gauge.

The max psi should produce 4.5v at the rail pressure transducer. Anything beyond that it will through a code. And idle rail pressure sure produce 0.5v. Anything below that and it will through a code.

So, I am just trying to get the known psi of idle and max on a 6.7 rail.
 
CLAYNDCITY said:
Assuming it IS linear (there will always be slight variations between units), that should be pretty easily calculated in an excel table, with a spread of 4.06V and 26700 psi. However, the resolution may be a bit "generalized. Divide 4.06 by 26700, multiply by 5800 and add .5 (your output voltage floor) and you get 1.353188V (to prove your calculation). That's pretty close to your 1.4V statement. You could possibly hook up an actual calibrated pressure gauge, and make a table of voltage measurements to see if the difference (between 1.35 and 1.4) was a constant and if so apply that to your table globally to refine it. But if you ever changed the transducer, you'd have to do it all over again.
Click to expand...

That's great. Thank you.
 
Rogue Diesel said:
I have a buddy who is a mechanical engineer and he is building me another rail pressure gauge for my 2010, 6.7. So, what he needs to know is the max PSI rail pressure of a 6.7 and the idle rail pressure of a 6.7. This is how he will set the parameters on the gauge.

The max psi should produce 4.5v at the rail pressure transducer. Anything beyond that it will through a code. And idle rail pressure sure produce 0.5v. Anything below that and it will through a code.

So, I am just trying to get the known psi of idle and max on a 6.7 rail.
Click to expand...

.5v won't be idle pressure, it'll be zero. It's completely linear between .5v-4.5v (0mpa - 200mpa) or zero psi to 29000psi
 
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