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Oil Pressure Sensor issue


doninphi
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Generic Oil Pressure Sensor wired in as:

5v+ out of ecu (red blue wire)  - Tested this

GND:  from ecu  (green wire)  - Tested this

signal: Wired to AN4 (white black stripe wire) - Continuity checked this

 

When I setup the 150psi sensor to show in Psi it doesn't move, shows 24psi when engine is off, start it and it doesn't move. 

 

I have two oil pressure sensors here, changing the ecu settings to show a 0-5v input display rather than KPa to test the sensor.

I plug one 10bar sensor in and I get a reading of 4.26v

I plug in the 150Psi sensor and I get a reading of 1.23v

 

To test the sensors I rigged up a bike pump to a sensor. I can feel the bike pump build pressure as you push it, and yet the voltage shown on screen does not change.

 

Thoughts?!?!? Surely two sensors cannot both be goosed.  

This is the 150psi sensor:

https://www.ebay.co.uk/itm/5V-PRESSURE-TRANSDUCER-SENSOR-STAINLESS-STEEL-150PSI-OIL-GAS-AIR-1-8-NPT/163553064354?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

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12 minutes ago, remski2 said:

Have you checked your cal table associated with it ?

Yes it was set to cal6  which was set as

0.5v = 0psi

4.5v = 150psi 

As the sensor settings said.

But the issue is why isnt voltage changing with pressure?? Rev it and it doesnt move. Surely it should respond quickly?

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If set to an oil pressure gauge. Its Kpa but I converted it to psi. 

If I set it to 0-5v gauge I can see the voltage coming in from the sensor.

That's beside the point though. I want to know why noth sensors seem stuck at a given voltage when given pressure. Or if I've wired it wrong etc....

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It sounds like the pinout is wrong.  There is no pinout information in the link to the item you gave so you are on your own a little.

All the brand name sensors with the metripack connector use the pinout below, so this is what I would expect it to be but you never know with the cheap Chinese stuff.

BVmF99F.png

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There are two further thoughts I will leave.

I know of at least one car locally that has caught fire due to the end blowing out of one of those sensors, luckily it was saved with minimal damage due to it happening on the dyno with plenty of extinguishers around, but it may not have been be so lucky if it happened on the road.  So perhaps you arent considering the cost of a failed sensor - it may just leave you stranded due to it failing and giving say a false oil pressure limit.  Sometimes when they fail they short the 5V rail so all sensors no longer work.  Or it could be as serious as loosing the car or engine.

The second factor is the tolerance of vibration.  I only really have experience with relatively harsh race engines so road car engines may be more forgiving, but most of the cheap sensors dont last very long if fitted direct to the engine - and I mean even the cheaper name brand ones such as honeywell px3.  Theses all need to be mounted remotely which if you add the cost of decent hose and fittings each end you are probably near the cost of a good sensor that will tolerate direct fitting.   

The only sensors I have have had little failures from when direct mounted:

Honeywell PX2.

Link/Variohm/Eurosensor

Bosch 0261230340 <this is my goto at the moment, decent price, temp sensor built in and have never had one fail.  Unfortunately the connectors arent that nice.

 

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Ordered the Bosch. I like the fact I'll have temp too.

I'll get it into the bay with wires long enough. I assume there are wiring diagrams online for it? 

5 wires. I'm guessing pos. Neg. Feed pressure. Feed temp. What's the 5th?

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Thanks so much. 

"Avoid allowing lubricant in the pressure port" how is that possible when its going in an oil way!! Haha.

Couldn't find one in the UK with the lead so it's coming from Oz. Think it's a gen Bosch lead too.

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4 minutes ago, doninphi said:

"Avoid allowing lubricant in the pressure port" how is that possible when its going in an oil way!! Haha.

German translation at a guess, suspect it means "sealant".

Forgot to mention, the temp part uses the std Bosch NTC calibration, the pressure side uses the TI 150psi calibration.

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15 hours ago, Adamw said:

It sounds like the pinout is wrong.  There is no pinout information in the link to the item you gave so you are on your own a little.

All the brand name sensors with the metripack connector use the pinout below, so this is what I would expect it to be but you never know with the cheap Chinese stuff.

BVmF99F.png

This solved it. 

I'm still going to upgrade to a Bosch at some point. 

The  Chinese wiring colours were wrong. Followed this and ignored colours. Works fine.

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On 5/12/2020 at 9:01 AM, Adamw said:

 

Bosch 0261230340 <this is my goto at the moment, decent price, temp sensor built in and have never had one fail.  Unfortunately the connectors arent that nice.

 

Thanks Adam, I found these sensors are used in late model mazdas as a cheap supply, but are these Ethanol compatible?  its not listed on the bosch site as an approved fluid. 

i want to use one for oil and one for Petrol/E85

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43 minutes ago, billsy said:

but are these Ethanol compatible?  its not listed on the bosch site as an approved fluid. 

I have never used them with eth yet but being an oem fuel pressure sensor when many countries have at least 10% eth in normal pump gas I expect they will be designed for it.

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