Fuel Pressure guage

[mr_minnis]

ts 2.6.04 MS3x 1.3.2

Something weird I noticed:

I have an aftermarket fuel pressure transducer set up as Generic sensor #1 set as PSI. I also have it setup as sensor 2 in kPa.
Under fuel pump and pressure I have sensor 2 listed as the fuel pressure sensor.

I set up a gauge for generic sensor 1
I set up a gauge for Fuel Pressure 1 PSI.

They don't display the same value when the engine is running. They are about 10 PSI off.

is that odd ?

[LT401Vette]

I would need to have your msq to see how it is set up.

[mr_minnis]

sorry. I forgot to attach

[LT401Vette]

It does look setup correctly.

Can you capture the raw ADC val and each of the gauge values all at one point?

Perhaps the negative 0V values are causing a problem with the interpolation?

[mr_minnis]

Sure. I will get that over the weekend. I think the gauge created under fuel pump and pressure is about right. It shows 40psi and the other shows 30.

It's not a biggie. Just odd.

[mr_minnis]

It does look setup correctly.

Can you capture the raw ADC val and each of the gauge values all at one point?

Perhaps the negative 0V values are causing a problem with the interpolation?

how do I do that. I cant find the option.

[LT401Vette]

Similar to how you got kpa and psi, In the Generic Sensors Dialog, sett up a 3rd generic sensor,but for transformation leave it set to raw.

[mr_minnis]

here is a screen shot:
the gauges that have a number at the end are from "sensors input2" I wasn't sure if it would convert the PSI to KPA. It does
The ones without numbers are from "generic sensor input"

I'm not sure why my fuel pressure is so high(should be 40, it was 40 till yesterday). Something happened yesterday and I think that is what caused it. I was done turning AE and pulled over, I turned on "long term trim" the car died and wouldn't start. after a minute or so tuner studio reconnected and said I had a sever settings mismatch. From some reason settings under "table switch" got turned on. I don't understand it.

You can plainly see something is weird in the calculations. It was never this far off. The generic sensor said 30 and the fuel pressure would say 40. Now it looks like both or all three are going off the KPA values

Its not my transducer that is faulty. I hooked up my variable dc supply and as I adjusted the voltage 0-4 it was off from what the scale i set up in generic sensors. I can't find a way to see what the ecu is seeing on input voltage on adc13. With .8 volts it was at 30 PSI

[jsmcortina]

Please post a datalog.

I've tested this on the bench and it works as I expect it to. In my case
sensor 1 (fuel pressure in psi) = 19 psi
sensor 2 (fuel pressure in kPa) = 134 kPa
sensor 3 (raw ADC) = 301

Those are all consistent with each other.

You have your sensor configured as a gauge (i.e. baro referenced) sensor.
The gauge I'm looking at is differential fuel pressure. (kPa.d)
My MAP is reading 151 kPa and baro is 102 kPa

So, absolute fuel pressure = 102 + 134 = 236 kPa
Differential fuel pressure = 236 - 151 = 85 kPa and that's what the TS gauge shows.

James

[mr_minnis]

#1 is a log from yesterday. when the motor starts 43 seconds is when they go about 10 apart (notice fuel pressure is about 40)
#2 is a log with the generic sensor disabled. Its weird to me that the gauges still move around
#3 is a log with them turned back on. notice fuel pressure is at 70


I guess what I am concerned about is something happened and now my base fuel pressure is 70. I can't find a mechanical problem.

[jsmcortina]

All of the calcs look ok to me.

James

[mr_minnis]

All of the calcs look ok to me.

James

What do you think is wrong ? could something be damaged on that circuit to cause it to be "off" on my unit? I have a power supply, I can send voltages in increments. is there a way for me to see what the ecu sees at the voltage level ?

can you tell me what the adc count should be per voltage? I think something is wrng at even though the transducer is sending 2 volts the ecu is seeing 2.5

Like I said something happened yesterday and caused the unit to die and think the dual table feature was turned on.

[jsmcortina]

Use a linear transform with 0V = 0 and 5V = 5.

James

[mr_minnis]

I set that up on a 4th sensor. I disabled input sharing and turned off the other 3. When I turn the ECU on and set up a guage for generic sensor 4, it shows the pressure as 542. This is with 2.6 volts supplied.

Is reloading the firmware a possible solution ?

[jsmcortina]

I set that up on a 4th sensor. I disabled input sharing and turned off the other 3. When I turn the ECU on and set up a guage for generic sensor 4, it shows the pressure as 542. This is with 2.6 volts supplied.

542 ADC counts = 2.6 Volts.

James

[mr_minnis]

why is generic sensor 4 gauge showing up as adc counts vs the 0-5 scale I set it up as ?

[jsmcortina]

I can only guess that you configured it incorrectly? It works for me.

James

[mr_minnis]

Attached is the current tune. generic sensor 4 set up as linear 0-5. gauge shows up as ADC. I will post screen shot and datalog when I get home.
I'm pretty sure it is setup correctly.

[jsmcortina]

I loaded your MSQ and it works for me. I get a 0-5V reading on sensor 04.

James

[mr_minnis]

ok Here is a screen shot of the sensor showing it is in adc even though it is configured as linear 0-5 volts. The wiring has 2.6 volts applied to it going to the ecu . there is also a log of the engine key on engine on and engine running.

please let me know whats wrong, what hardware .