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Ducie54

Fuel system type Map to FP sensor

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Im after some advice as to why when switching fuel pressure input from map reference to FP sensor the AFR go RICH. Im using all new sensors, link 5 Bar map and 100 psi Honeywell fuel pressure sensor. I tested the Fuel rail pressure against a external dial gauge and the calibration is fine. Map sensor calibrated ok in the software. Map sensor is using a short Dash 4 hose to intake manifold that sits above the intake manifold.

Monday ill make up a test adapter for the map sensor.

Fuel table in modeled mode is in the high 90's on a sr20 which seems high at idle. In the log files for some reason fuel pressure does not show even tho AN13 shows fuel pressure. Not sure if this is the reason for my troubles. Or are am i missing something simple?

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Edited by Ducie54

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It seems as though you have fuel added to your warm up enrichment. You will want to set your IAT correction and Warm Up Enrichment table to all zero when in modeled fuel equation mode. High 90's is a tad high in modeled. Just depends on the rest of the engines characteristics and settings. The dead times correct? Small pulse width adder? This engine seems pretty cold as well and it is going back and forth between warm up enrichment and when getting cold is throwing off the Charge temp. coefficient table. Zero those tables out and give that a try. Do you have AN volt 13 as a GP pressure or set to fuel pressure? The ecu is a bit confused. Post a log file so we can take a look.

Cheers

Edited by Rich RDE

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Thanks for your input Rich. Dead times were supplied by Motec and Short pulse width adder valves were worked out for me by the senior engineer at ASNU. Going by the factory running temps the recommended temp range is 78 to 83 deg C. Im running electric water pump so still dialing that in as well.

Warm up enrichment is now at 0 when up to operating temp, Charge temp is all water temp bias at 100% until i can at least get this thing to rev.

Tested the map sensor against the 100 psi water temp sensor and scale was good. Connected a brake bleed sucker to the Map and is reads negative psi so sensor must be good. One thing i did notice is when it was set to Link 5 Bar at high boost it was 5 psi out compared to the Honeywell 100 psi sensor. When i swapped to SRS 5 Bar it matched the Honeywell sensor.   

ANV 13 has the function of Fuel pressure from the drop down box. So unsure whats going wrong there.

I had i bit more of a look today and noticed differential fuel pressure went all weird when swapping to FP sensor. Im thinking i have the axis of the dead time table wrong :( I have the Y axis as battery voltage and X axis as Differential fuel pressure. Is this right for modeled fuel or should X axis be Fuel Pressure  

For some reason i cannot attach log as its saying the log is too big even tho it only run for a few seconds

5NJ5Rg.png

Edited by Ducie54

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All sounds pretty solid. Where is the map sensor hooked up? So the issue is the differential fuel pressure here and now I understand a little better what is going on. In the modeled equation it is calculating Base fuel pressure - MGP which gives you your Differential. The ECU needs to know the correct dead times at your specific given fuel pressure to compensate for. You need to give it your base fuel pressure to start with and make sure that is correct. You have the axis setup correctly. What's interesting is how the differential fuel pressure drops as the engine starts to go into that weird oscillation. Something seems a bit off to me. Can you email me a log? Also if you could supply your base file or the fiel you are using so I can take a peak. All the firmware up to date? I still find it very odd that the ECU does not see the Fuel pressure. Is this correct? Have you pulled up the run time values to verify? linkprotuned@gmail.com

Cheers,

Rich

Edited by Rich RDE

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When you've changed away from MAP referenced, do you still have a vaccum line on the FPR?

If you dont have a vaccuum reference, then you need a 3D deadtime table.

If you're using a 2D table, it's possible that the ECU is extrapolating the deadtime just from that single row and coming up with some weird numbers.

Check in the log and sanity check the deadtimes / make sure they match your table.

Your injector deadtimes stay a lootttt closer to values on a 2D table when you keep the FPR vaccum referenced. (regardless of whether you're monitoring fuel pressure)

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David doesn't this change when going to FP sensor only support a rising rate regulator? I would imagine that this would only be the case if you had a FP control that you boosted DC too that you would not need the vacuum line to the FPR? Maybe I am mistaken? Seems as he is using a 3D table for this and the FPR is still rising rate? Still does not explain why the Fuel pressure is not reading which it is now trying to use as a main calculation in the equation.

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Still does not explain why the Fuel pressure is not reading which it is now trying to use as a main calculation in the equation.

This is a bug. Currently if you use ANV12 or higher for fuel pressure it does not work. We have an update coming shortly that will fix this issue and some others.

Scott. 

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This is a bug. Currently if you use ANV12 or higher for fuel pressure it does not work. We have an update coming shortly that will fix this issue and some others.

Scott. 

Thanks Scott, saves me any more headaches working that out. Found out today the dead time data supplied by Motec is battery voltage and fuel pressure. I had it setup as differential fuel pressure. Minimum effective pulse width is also too low causing high valves in the fuel table.

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Ducie54  sometime injector data say only fuel pressure, since they are tested outside the cae. 

During operation it's ALWAYS differntial fuel pressure that counts. So you must setup your injector death time axis as differntial fuel pressure vs Batt volt or visa versa!

 

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Hi Mapper, Is that with both Map referenced and fuel pressure senor referenced fuel system type tho?

I might try setting the dead time axis to fuel pressure and fuel system type to fuel pressure senor and see what the difference is. 

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Differential fuel pressure is what the main calculation goes off of for fueling in modeled mode. So this would be why the axis is setup as mentioned by Mapper.

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When Fuel Equation Mode is set to Modelled and Fuel System Type is set to:

  • 'None - No FP Correction',  differential fuel pressure always equals zero and the ECU makes no changes to injector pulse width based upon differential fuel pressure.
  • 'MAP Referenced', differential fuel pressure always equals 'Base Fuel Pressure'. This is because the pressure being applied to the fuel pressure regulator and the inlet pressure are equal,
  • 'FP Sensor', differential fuel pressure equals Fuel Pressure less MGP. The ECU will change the effective injector pulse width based upon changes in differential fuel pressure even if your injector deadtime table does not have differential fuel pressure as an axis. However, it will only change the deadtimes based upon differential fuel pressure changes if the differential fuel pressure data has been entered in the injector deadtime table.
  • 'Returnless', differential fuel pressure equals 'Base Fuel Pressure' less 'MGP'.

I suspect most people will be using the MAP referenced or FP Sensor modes. If you are running the MAP referenced mode then there is no point in entering the differential fuel pressure data in the deadtime table. If you are running the FP Sensor mode then it is worthwhile entering the differential fuel pressure data if you have it available. 

Scott

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This is a bug. Currently if you use ANV12 or higher for fuel pressure it does not work. We have an update coming shortly that will fix this issue and some others.

Scott. 

I moved the fuel pressure input over to ANV 9 and still will not show fuel pressure.

Fuel_pressure.thumb.jpg.ab88776a32e17b58

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