Oil Pressure Sensor Issue

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sshinx1
Posts: 10
Joined: Sat Dec 17, 2016 2:05 pm

Oil Pressure Sensor Issue

Post by sshinx1 »

Hi,

I have been have a problem with the oil pressure sensor on my 99 impreza, running a S6 with various sensors and a toucan display. Problem is we are seeing low oil pressure on the toucan and the ecu is cutting the engine, we are only seeing 2 bar of pressure on toucan but I know the oil pressure is normal as we had a manual gauge fitted at the same time (seeing over 6 bar when started), have swapped it with the fuel pressure sensor(same sensor) and have also a new sensor and still the same problem, I was thinking it couldnt be the wiring as i am getting a reading? has anyone any ideas?

Was all working perfect before a sensor went faulty and was replaced

Thanks.

Shane.

stevieturbo
Posts: 867
Joined: Sun Dec 07, 2008 2:04 pm

Re: Oil Pressure Sensor Issue

Post by stevieturbo »

Exactly what sensor are you using, and is it 100% confirmed as calibrated correctly ? ( and also what sensor before you replaced it with another ? )

And where is it attached ?

And the ecu and Toucan reading differently would be a tad strange, given the Toucan receives its information from the ecu ?

More details needed.

sshinx1
Posts: 10
Joined: Sat Dec 17, 2016 2:05 pm

Re: Oil Pressure Sensor Issue

Post by sshinx1 »

The sensor it connected to a t piece which has it and the original sensor for the oil light attached as well into the original loctaion for the sensor at the front of the engine.

Exact same sensors where used, unsure if they are calibrated correctly(they were brand new)

Sorry should have clarified i was going by the toucan reading not what the ecu is reading but I assume they would be the same?

I will confirm what type of sensors im using.

Thanks

sshinx1
Posts: 10
Joined: Sat Dec 17, 2016 2:05 pm

Re: Oil Pressure Sensor Issue

Post by sshinx1 »

kasensors
Type asmp
range 0-10 bar sg
Output 0.5 to 4.5 vdc
Supply 5 vdc

stevieturbo
Posts: 867
Joined: Sun Dec 07, 2008 2:04 pm

Re: Oil Pressure Sensor Issue

Post by stevieturbo »

Very odd for a KA sensor to go faulty.

And again it makes no sense for the Toucan to read differently from the ecu given they ecu transmits the data to the Toucan.

And as with the other sensor thread....if there is any doubt whatsoever test...test....test.

In this case you need to both pressure test the sensor, AND your mechanical gauge at the same time from a known pressure source.

And obviously it isnt the sensor itself you calibrate, but you need to calibrate the ecu sensor linearization for your specific sensor.

And whilst most threaded/industrial type sensors are typically 0.5-4.5v range, definitely not all pressure sensors are like this.

Various MAP sensors, OEM etc are not always like this and some are not even linear within those ranges either.

So again....test the sensor and ensure any calibrations used are correct.

TimH
JT Innovations
Posts: 621
Joined: Wed Sep 01, 2010 2:51 pm

Re: Oil Pressure Sensor Issue

Post by TimH »

The clue maybe that it was OK until a sensor (presumably not this oil pressure sensor?) was replaced and then it started playing up; if I've understood right?

So either something was disturbed/broken when that other sensor was replaced, or something subsequent has caused the pressure sensor to fail. Although Stevie is right that the KA ones rarely fail, it can happen - but the usual failure is a high pressure spike taking out the sensor; this is unlikely given that you have the braided hose which damps any transients.

Does the Toucan show any variation if pressure or is it stuck at 2 bar? If its stuck, the sensor could have failed.

If it were me I would do a rough-and-ready test. Unplug the connector to the sensor and get a short piece of wire. Short the signal pin first to the ground pin and then to the +5V pin of the connector on the cable and see what Toucan (or SCal) says. It should swing from 0 bar to 10 bar. If not, then there's a wiring fault I would think.

The sensor connector is in a triangle-shape. The pin at the apex of the triangle is the signal; the two next to each other are sensor ground and sensor +5V.

sshinx1
Posts: 10
Joined: Sat Dec 17, 2016 2:05 pm

Re: Oil Pressure Sensor Issue

Post by sshinx1 »

Thanks for the reply Tim!

It Fluctuates around 2 bar and rises when reved as it normally would, we had the manual and electronic sensor connected at the same time, manual was reading 6 bar as normal and toucan was showing 2 bar.

Problem has only surfaced since the previous sensor failed. we have tried 2 new sensor and still the same problem

I will try your suggestions and see if its reading correctly

Thanks

stevieturbo
Posts: 867
Joined: Sun Dec 07, 2008 2:04 pm

Re: Oil Pressure Sensor Issue

Post by stevieturbo »

I'd be surprised if the original sensor failed at all here.

Post a datalog of the behaviour of EOP, and also include the raw analogue voltage of whatever input you are using for it.

sshinx1
Posts: 10
Joined: Sat Dec 17, 2016 2:05 pm

Re: Oil Pressure Sensor Issue

Post by sshinx1 »

Bit of an update, only got a chance to look last night as we are going to try a be ready for racing on saturday :roll:

Seems to be when we move wire around the blue ecu plug that this causes an issue with the oil pressure dropping or even just knock the ecu, I have since stripped all the loom tape off and separated wires as best i can and checked that there was no obsequious faults in connections, since i have done this i cannot get the oil pressure gauge to mess about again no matter how I move wires etc( before movement at all your could see the gauge dropping right down and up again)

So thinking that it either has to be a bad connection or could it be inference with signal wire??

Also another thing i noticed once i moved wires and it was still affecting gauge that the revs would rinse slightly and water temp gauge would play about as well.

Tim I tried the test you suggested on the pins, this worked once where it rose to 6 bar but any time i link it out now the gauge never moves, but once connected it reads correctly.

So i'm best bet would be to re-do all sensor connections and check for any breaks etc?

I know this is long winded but I would love this sorted :D

Thanks!

Slowie
Posts: 105
Joined: Thu Jan 17, 2013 7:30 am

Re: Oil Pressure Sensor Issue

Post by Slowie »

Yes, that sounds like bad crimp/solder connection, or a wire that was nicked when the insulation was stripped, etc.

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