Oil pressure and warning light :(

[wildejon 7]

OK, this is interesting and confusing.

With just the ignition on, if I cut the pressure sensor out of the loop, the gauge goes to full (photo attached) - which I guess means I need to replace the sensor and that the wiring is OK.

If I cut the pressure sender (the low pressure switch) out of the loop, I don't get a STOP or low pressure light - should it? (I think yes, or it would always be on)
 

I cannot find the correct plug to check under the dash, there are SO many wires and I don't know know which to check 

AFAIK, it isn't connected to a fuse so I can rule out all of that wiring. That still leaves a lot though.

I also know it was orange, but so are many of the wires 

Is it a floating connector or is it attached to the side wall?

 

Thanks! in advance!

Edited July 6, 2023 by wildejon

[wildejon 7]

Progress:
Low pressure light works!

STOP light doesn’t (I thought they were connected)
I think I need to replace the pressure sensor as it’s is mis-reading, I can’t get the old one off tho. It’s got some black plastic nut over the small one, ideas?

[wildejon 7]

But the sensor gets 6V, is that normal?

[wildejon 7]

OK so... I still think this is purely a wiring problem as I know the engine pressure is fine but...

 

The gauge shows low pressure and the low pressure and STOP lights come on.

The pressure switch does have a 12V feed.

The pressure sender has a 6V feed. I assume this isn't normal as the internal gauge also reads half of the mechanical one.

 

I am totally at a loss as what to do now. 

I don't know where the feed comes from or how I would sort it out if I did know. Any ideas? 

[wildejon 7]

Sorted! There are actually 2 problems.

the sensor (switch) was faulty. No more false warnings now it’s replaced!

 

There are still issues with the gauge giving a low pressure reading but I’ll leave that for another time.

 

Thanks for the help along the way.

[welshpug 1,661]

I dont recall ever checking what volts the gauge runs at, but if the engine loom has the brown multiplug in the middle under the afm area I would disconnect this and check the volts there and the condition of the terminals

Edited July 7, 2023 by welshpug

[pug_ham 244 3 Cars]

Glad you have some resolution to your problem Jon.

On 7/3/2023 at 8:20 PM, wildejon said:

I removed the brown multiplug, now it has nice waterproof connections, yay.

 

2 hours ago, welshpug said:

if the engine loom has the brown multiplug in the middle under the afm area I would disconnect this and check the volts there and the condition of the terminals

The brown multiplug has already been replaced, can't account for the condition of the wires within the loom but they are usually pretty black from my experience which could explain the drop in voltage if the starter solenoid wire is anything to go by.

 

g

[PhilNW 44]

If you can decipher them the wiring diagrams can be seen here

 

http://prepparts.free.fr/docs/doc2.html