Bouncing fuel pressure sensor

[svein]

Hi!

I am playing around with the fuel system of my car at the moment - and as I removed one out of two filters, the fuel pressure gauges started bouncing a LOT. Is it possible to do something with this in the software, or is a gauge snubber the way to go here?

Cheers,
Svein

[ArT]

In some configurations it occurs. I can do longer averaging in software for you. How fast read do you need for pressure? At the moment it is 10 samples per second. In which input do you have connected sensor?

ps. please make sure that sensor has good connection to ground (black wire in utcomp)

[svein]

Wow, if you can do that, it would be really cool!

To be honest, I don´t really know what would be the "perfect" average. It is good to be able to see the fuel drop when I accelerate, but it seems to me like I am reading quite a bit of the pulses from the lift pump. Maybe cut it in half and do 5 updates/sec? What do you think?

At the moment I am reading fuel pressure three places:
Acd1("oil pressure sensor"), Acd2("boost pressure sensor") and Acd3("fuel pressure sensor").

It might sound crazy, but I am in the process of converting my car to run on WVO, so it´s useful to see the fuel pressure different places in the line (both for diesel and veg oil).

[ArT]

One more question All 3 fuel pressure readings are bouncing in the exact way or only one (which Adc input?) ? Could you share movie?

[svein]

Haha, keep the questions coming!

Yes - all the readings are bouncing. The pressure sensor closest to the injection pump is bouncing quite a bit more than the sensor closer to the lift pump. It seems like the filters are acting like "buffers" and is taking away some of the pressure spikes.

I the plumbing of the system is like this:
lift pump ->pressure sensor(1 for diesel/1 for veg oil) -> filter -> line -> fuel selection valve -> filter -> pressure sensor -> IP.

I have a movie of the gauges bouncing at idle (which is little compared to the bouncing during driving), but the attachment was unfortunately not allowed here. Could I email you a dropbox link, perhaps?

Thanks again,
Svein

[ArT]

I see on movie that "oil pressure" reading is constant, only "fuel pressure" and "boost pressure" are bouncing (I know that all 3 are fuel pressure in your setup). Could you share me your UTCOMP settings file? (you can export it from application). I'll try to prepare you modified dedicated firmware with filtering.

[svein]

Ah, yes, I forgot to mention that!

The "oil pressure" is pre filter on the wvo side, "boost pressure" is pre filter on the diesel side, and "fuel pressure" is common just before the injection pump.

In the video, the car is idling on diesel, so there is no lift pump running or fuel being consumed on the wvo side, hence the stable reading. I will send you the settings file asap.

Thanks again,
Svein

[ArT]

Dear Svein,

I've sent you on PM firmware with modifications. I added longer averaging for pressure sensors. Please let me know about results when you update it and test it.

BR
Artur

[svein]

Thanks a lot! This is truly amazing customer service!!!

I will keep you posted with the results!

Cheers,
Svein

[svein]

Uploaded the new software today before going out on a longer drive. It works wonderful! It´s still rather bouncy on the gauge closest to the injection pump - I suppose the demand from the IP is quite fluctuating - but now it´s readable and understandable, so I´m very happy with the update! Thank you so much!

Cheers,
Svein