No oil pressure shown via OBD socket ?

[Crucian]

I have an aftermarket obd hud fitted but there is no oil pressure displayed on it (it has an oil pressure display but just reads 0) any suggestions ?

I assume there will be no oil pressure displayed via VCDS but will check later this week

[sepulchrave]

3 minutes ago, Crucian said:

I have an aftermarket obd hud fitted but there is no oil pressure displayed on it (it has an oil pressure display but just reads 0) any suggestions ?

I assume there will be no oil pressure displayed via VCDS but will check later this week

 

That will be because there is no oil pressure sensor fitted!

[Crucian]

That'll be why then 😂

[Crucian]

I'll get me coat

[sepulchrave]

9 minutes ago, Crucian said:

I'll get me coat

 

Have you got a coat?

[Ootohere]

@CrucianYour Mk2 vRS 1.4 TSI Twincharger might well show the Red Oil can light and the Low Oil pressure light, and maybe even before the Yellow Low oil can light or message shows.

The OIl level might be 1.3 litres low and no low oil light but just 1 litre low on oil from the correct quantity and cornering and you might get the Low Oil Pressure warning. 

[Crucian]

@Rooted

I don't have an oil pressure issue I was just wondering why it wasn't displayed

but thanks anyway

[thomasaspin]

Most cars post 2000 have an oil pressure sensor I would find it hard to believe the 1.4 twincharger doesn’t have one 

[Breezy_Pete]

No, they have oil pressure switches. Simple things that just short a wire to earth at a given pressure. Not able to give a pressure reading.

[Bertie90]

my 2007 roomster has a blanking plate where the oil level sensor is. 

 

I have a MX5 which indicates the oil pressure on the dash as you drive and even that one is not real, it's some sort of simulation driven by the revs. You need to fit one and code it with VCDS

[skomaz]

2 minutes ago, Bertie90 said:

I have a MX5 which indicates the oil pressure on the dash as you drive and even that one is not real, it's some sort of simulation driven by the revs.

 

Yours must be newer MX5 than mine then ..   the older models got a pukka sensor.

Edited 1 November, 2023 by skomaz

[J.R.]

VCDS being used to code a sensor on a Mazda! 😯

[thomasaspin]

6 minutes ago, J.R. said:

VCDS being used to code a sensor on a Mazda! 😯

Original op has a fabia ….  

[Bertie90]

6 minutes ago, J.R. said:

VCDS being used to code a sensor on a Mazda! 😯

of course not, I was referring to the original question.

 

2 hours ago, skomaz said:

 

Yours must be newer MX5 than mine then ..   the older models got a pukka sensor.

pre 1995 had real ones. 

[Breezy_Pete]

Sump sensor is for oil level and temperature. 

 

[KeithCheetham]

3 hours ago, Bertie90 said:

even that one is not real, it's some sort of simulation driven by the revs. You need to fit one and code it with VCDS

 If it was a simulation any drop or total loss of pressure would not be identified as any reading aligned with revs would still show pressure. It may be digital taking a signal from a pressure transmitter, or piped with a tapping from a oil gallery. Most cars do not have a constant pressure and will generally show some rise in pressure with the revs, until a point where the pressure relief valve actuates to maintain a pre-set pressure.

 The oil pump is generally a constant displacement type with the flow going down oil galleries and through bearing clearances. The small clearances will give some throttling of the flow, creating a back pressure as seen on a gauge (finger off then partially over end of hosepipe to understand). As the flow increases with the revs, the clearances cannot accommodate this increased flow causing more back pressure seen as a rise on the gauge. This is why a pressure relief valve, which technically bleeds flow, is needed as the pressure would keep increasing without this control.

 The ECU probably does not have any logic to convert a variable signal from an oil pressure transmitter to a read-out for the instrument cluster as it currently does with water and oil temperature. Breezy_Pete may be able to expand on the operation philosophy of the oil level, I know some can actually give a measured level.

Edited 1 November, 2023 by KeithCheetham

[Bertie90]

it's a well known fact that Mx-5s after a certain year don't have a real oil pressure reading. You can research it if you wish, I don't care that much to be honest, we have digresses from OPs post in typical forum fashion, my apologies.