Fuel pressure sensor suddenly stopped working

[svein]

Hi!

I just added a fuel pressure sensor (the digital one from the reveltronic shop) on my car. It worked like a charm for a couple of days, until it suddenly stopped showing any pressure. I can se some minor movements on the oscilloscope, but in general it shows 0 psi.

I know my fuel delivery pump is running, so there should be a positive pressure - I am however afraid that there is something wrong in the fuel system and the sensor is correct. Has anyone experienced something like this? Could the sensor head itself be clogged?

Thanks so much for any help!

Cheers,
Svein

[ArT]

Please check your voltage output from sensor. In atmosphering pressure (engine off) it should be around 0,5V (for ~1bar).
If you have ~0,5V output then sensor is fine (in such case please check connection to UTCOMP).
If you do not have ~0,5V output please check power supply for sensor. Sensor should be powered from +5V (and ground).
Some people connects +12V to sensor which will damage it - please check it also if you have +5V.
If power supply is fine and sensor output does not change, please contact with REVELTRONICS Store with your order number (it has warranty) or send me your order number on PM and I'll help.

[svein]

When I checked it with the computer yesterday, it was measuring around 0,47V on the input, so I suppose the sensor is good.
I am unfortunately running without any filter between the tank and the sensor at the moment (this is subject to change), so I was afraid that it maybe could have been clogged with debris. Is that a possibility, and if so - is that something that is repairable?

It seem slike I have some other issues with the fuel delivery as well, so It could very well be that it measures all good. It´s just a bit hard to pinpoint the problem when both the fuel lines and the sensor is new, and the car runs good even though I´m missing fuel pressure. I will do some more fault-finding this weekend when I have some time.

Thanks again!
Svein

[ArT]

Hmm sensor's output looks good so it seems that sensor is fine.
Sensor is not demonountable but you can try to clean it in ultrasonic bath with isopropyl alcohol (IPA) and there is a chance that it will help. Please let me know about results.

[svein]

Hi again!

I put my thermal suit on and had a good day crawling under the car in the snow. Re-routed the fuel lines and changed the lift pump, and suddenly the sensor showed pressure again - Im quite confident the sensor was right all along, and I fucked it up with my fuel lines.

I have one sensor pre and one post my main diesel fuel filter, and I am reading a slightly bigger pressure drop than expected. The pre filter sensor is mounted directly into the fuel filter head, while the post sensor is t-ed in with a fitting like this:
https://www.glowshiftdirect.com/3-8-fue ... g-adapter/
When the pressure sensor is screwed all the way in, I can see it blocking at least 1/3 of the fuel line. I´ve been thinking maybe I should try to unscrew the sensor a bit and seal it off with thread sealant. It´s probably a stupid question, but would this be a worry to cause leaks?

Thanks again,
Svein

[ArT]

Thanks for good news

Hmm I see two solutions:
1. use 1/8npt -> 1/8npt thread adapter (you will have more space), eventually
2. use blue locktite glue or thread sealant , but thread is conical (/ \ not | | ) so if you will have too much space there is risk of leaks (thread sealant should be better, need to test it).

[svein]

I solved a lot of issues in the end by a combination of making a custom temp/fuel pressure fitting and getting a new filter before my lift pump. Both changes to the fuel system gave me less restrictions and now I have good readings of the fuel temperature as well:

2019-02-06 00.03.44.jpg (1.4 MiB) Viewed 5422 times

[ArT]

Thank you for your feedback and sharing good solution