Steve V's Automotive
Member
Eric- can you please post the pressure adjustment table when using fuel pressure correction- Thank you 
Fuel Pressure Correction table
- Thread starter Steve V's Automotive
- Start date
Fuel Pressure Correction Setup
For fuel pressure correction, you will need to create a generic sensor for the fuel pressure sensor, and calibrate it for KPA. The fuel pressure correction works in KPA only.
You will use that KPA generic sensor for the correction. Fuel pressure tends to bounce around a lot due to pulsations in the fuel rail, so you may need to set the lag factor on the generic sensor page very low like 15. Sometimes even putting an orifice in the line to the sensor might be necessary to smooth it.
See the following picture for the fuel pressure correction settings. On the graph, you might need to play with scaling to make it look right (the little boxes with the 3 dots in the top corners).
For fuel pressure correction, you will need to create a generic sensor for the fuel pressure sensor, and calibrate it for KPA. The fuel pressure correction works in KPA only.
You will use that KPA generic sensor for the correction. Fuel pressure tends to bounce around a lot due to pulsations in the fuel rail, so you may need to set the lag factor on the generic sensor page very low like 15. Sometimes even putting an orifice in the line to the sensor might be necessary to smooth it.
See the following picture for the fuel pressure correction settings. On the graph, you might need to play with scaling to make it look right (the little boxes with the 3 dots in the top corners).
Steve V's Automotive
Member
That's what I couldn't find thanks!
I am using same table for PWM and I can not select custom correction. However the table is active in the tune.
I am using same table for PWM and I can not select custom correction. However the table is active in the tune.
I'd like to understand how this can be used. I can see Fuel Pressure correction working well for a PWM controlled fuel pump as ECUGN can control the fuel pump by modulating but for stock type car where the fuel pump is really controlled by on/off, how is FP correction used (if at all)?
Is it actually controlling the fuel pressure some how or is this another variable included into the overall fuel calculation and is really just affecting the injector duty cycle to compensate for drops/spikes in fuel pressure?
Is it actually controlling the fuel pressure some how or is this another variable included into the overall fuel calculation and is really just affecting the injector duty cycle to compensate for drops/spikes in fuel pressure?
It doesn't change fuel pressure, it adds/subtracts to the fuel calculation, to attempt to compensate when the fuel pressure is not maintaining the proper differential pressure.
If your fuel pressure is set to 43psi (line off), then normally you should always have the 43psi differential regardless of boost or vacuum. If it starts to fall, for example, the fuel pressure correction will increase duty cycle. If you don't have enough fuel volume (failing pump), it can't really fix that though.
If your fuel pressure is set to 43psi (line off), then normally you should always have the 43psi differential regardless of boost or vacuum. If it starts to fall, for example, the fuel pressure correction will increase duty cycle. If you don't have enough fuel volume (failing pump), it can't really fix that though.
Is the correction factored determined by what ECUGN thinks should be the right pressure and compares it to the actual? I assume it calculates the expected pressure from the Static/Target input by the user and then add the MAP reading to it?
But how is the curve determined? Is this sort of trial and error thing?
If it's added to the fuel calculation anyway, would the AFR compensation correct for this anyway?
I can see this as being another good parameter to have available to adjust, especially for setting up a car where the owner may not be a tuner and just wants to drive the car.
Mike
But how is the curve determined? Is this sort of trial and error thing?
If it's added to the fuel calculation anyway, would the AFR compensation correct for this anyway?
I can see this as being another good parameter to have available to adjust, especially for setting up a car where the owner may not be a tuner and just wants to drive the car.
Mike
Yes, the ECU calculates what the differential pressure should be based on the user target setting, and monitoring manifold and fuel pressure. It will show up in a log as Fuelpressure1_kpa. The curve is based on how much more pulsewidth is necessary to maintain the same flow at a lower/higher pressure. There is a small deadband in the middle. Normally you don't need to change it.
The AFR wideband correction will correct for the same issue, but after the fact.
The AFR wideband correction will correct for the same issue, but after the fact.
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Thanks Eric. I think I get it and this seems to be really useful once it gets all set up.
I think I understand that when set for "Custom correction" it will use the Pressure adjustment table but I noticed that the default setting is Vac Referenced.
If the pressure sensor is defined and present, is ECUGN doing anything with fuel pressure correction when using Vac Referenced?
I think I understand that when set for "Custom correction" it will use the Pressure adjustment table but I noticed that the default setting is Vac Referenced.
If the pressure sensor is defined and present, is ECUGN doing anything with fuel pressure correction when using Vac Referenced?