Superlight R500 K Fuelpressure Sensor fail / STACK Dash

[Caterhamburger]

Hello PistonHeads,

i just bought a R500 and erverything is fine so far, but i have a question about the Stack dash.
All parameters of it work, only the fuel pressure sensor works wrong way, and shows me 99,99 , at least i believe its the number and it stays and doesnt change.
Can anyone tell me where the sensor is placed in the car, so i can change it, or any other ideas??

(PS: sorry for the bad english, shool is long time ago )


greetings from germany

[sfaulds]

There is no sensor as standard - the connector for that channel will be hanging around the steering column under the dash.

[Caterhamburger]

Hi sfaulds,

whats the usual way to get this done, i just don't understand why a fuelpressure sensor wasnt fitted there , i think its necesarry for maping the engine, as sample on a dyno?
But if this is the standart for the "R500K" i will upgrade it my self, so i might need a sensor wich fit the STACK right?
Has anyone done this befor?

[fergus]

Caterhamburger said:

Hi sfaulds,

whats the usual way to get this done, i just don't understand why a fuelpressure sensor wasnt fitted there , i think its necesarry for maping the engine, as sample on a dyno?
But if this is the standart for the "R500K" i will upgrade it my self, so i might need a sensor wich fit the STACK right?
Has anyone done this befor?

Hi. That's the job of a fuel pressure regulator. For a given fuel pressure, the injector open time can be set in a map at various load and rpm sites. If your fuel pressure falls at very high load for example, a map could compensate for this by increasing the injector opening times at that point in the map. If the duty cycle exceeds a threshold (potentially around 90%) then you may want to consider an injector with a slightly higher delivery rate. I don't think the std R500 ECU takes account of fuel pressure, and therefore has no closed loop way of compensating for this.

On a dyno, typically, as long as the Air/Fuel ratios are known, then as long as the duty cycle of the injectors isn't exceeded, you don't *need* to know the fuel pressure precisely.

[Caterhamburger]

Okay, i undertand.
And if i would place it, even if its not necesarry for?

[fergus]

Caterhamburger said:

Okay, i undertand.
And if i would place it, even if its not necesarry for?

If your ECU does not require a signal from the fuel pressure sender, other than potentially using this as a sensor input feed for the dashboard, I'm not sure why you would need to replace it. If you did choose to replace it, you would need to know how the dash has converted the 0-5v sensor output to a number on the dash, and whether the curve is linear, etc. I would imagine stack would have a specific part number for the sender their dash is calibrated to.

Not having real time fuel pressure data for a road car wouldn't concern me personally.

[DCL]

I think we've had this discussion on here not too long ago.

Fuel pressure can be a very misleading parameter to measure as temperature can alter the viscosity of the fuel. That's not an issue for the engine as it's the quantity of fuel that matters, not the pressure at which it is delivered (ie the quantity of fuel delivered remains the same). So watching fuel pressure can be unnecessarily stressful. It's really just for the 'techies' that can factor everything in, and why it is seldom seen on road cars.

[Caterhamburger]

thank you DLC,

thats the main reason for me, because i want to have it. The STACK has the parameter so i would like to have the fuel pressure on the display, thats all!
But the problem is, where is the right place to install and what the right sensor to use
(rail from the fuelpump? Fuelrail? Cut out a piece and put a hydraulic connector in it? and wich is the correct sensor?)

[sfaulds]

You'll need an ST745 or equivalent. A 745 has a 1/8 NPTF thread, so you'll need an inline adaptor for that and a suitable extension (4 pin mini sure-seal to spade).

[Caterhamburger]

Okay,
So has anyone done this before and some pictures of the installed sensor