What is this wire for? (oil temp?)

[Techspy]

Anyone know what this wire is supposed ot be connected to? I am thinking it is the oil temp wire (my oil temp guage isn't working) but I can seem to find the sender unit that it should connect to.

 

Thanks

Edited March 1, 2013 by Techspy

[Vulcan Grey]

believe that is for the Alternator

 

[CHANGES]

if its not the alternator then It looks to me like the oil warning light wire

which should be brown and white.

If so it fits on one of the two terminals of the transducer situated under the

inlet manifold and above the starter. Its a fiddly spot to get at but can just

be seen through the inlet manifold next to the c/c pipes.

In the pic's you can see the unit with the two terminals on. above it is the

knock sensor on the block and to the left adjacent to the oil take off to the

turbo is the oil temp sensor. If this is not working it may just need a clean

for a better contact, this wire does not have an insulating shield fitted to the

connector and is yellow an red.

the pic's should give you an idea where to look..

  

Edited March 1, 2013 by CHANGES

[Techspy]

Thanks guys. I will take a look at both of those locations.

 

Changes, that is one clean engine!

[Techspy]

Ok, it isn't the alternator wire. That one is connected. I think it is for teh oil light but there is only one connection on the sender unit and the other wire in the sleeve with the unconnected one is connected to the only terminal on the sender unit. See picture.

 

So, if that is for the tell tale oil light, it shouldn't have anything to do with the oil temp gauge not workign right?

[ramjet]

What colour is the wire and do you have a circuit diagram for your car?

[Techspy]

It appears to be brown with a white or yellow stripe. Yep, I have the service manual and I see the diagram for teh oil temp gauge going to the sender but it doesn't say whether the sender has 2 connections and/or what the other wire/connection is for.

So I am guessing the sender is not teh right one being it only have one connector. I do have 2 more senders (from when I owned the car before and was trying to troubleshoot low oil pressure readings at idle). Maybe I will try installing one and see if it fixes the oil temp gauge.

 

Any idea how I can test these units? Any idea what ohm it should read from the connections to teh ground?

Edited March 3, 2013 by Techspy

[Techspy]

And according to this picture, the oil temp sender is separate.

Ok, so I have a brown with yellow stripe connected to the oil temp connector with the yellow arrow. So the disconnected wire is brown with white stripe and I have no idea where it is supposed to be connected.

 

I think the oem oil pressure sender had the wire going to the gauge and a ground going to it and the single connector sender grounded to the block via the sender chassis. So maybe that wire is a ground for the oem sender unit.

 

So, how to get my oil pressure gauge working?

 

Man, I forgot how "interesting" it is to won an Esprit...

[ramjet]

I will try and have a look at mine a bit later. Can't at the moment as just got back from a drive and things are a bit warm. Will check and see what I find as everything on mine works. Just hope I can see it all.

[J400GED]

John,

     Does your oil pressure warning light illuminate when you key on before you start the car?

 

 

Ged

 

 

 

 

 

[ramjet]

OK John. I had a look at mine and I can confirm that there are 2 wires going to the oil pressure gauge. One is the wire you have which is disconnected and the other is what looks like a solid brown wire going to the other pin on the sender.

The sender on my engine looks like the sender in Dave's pic. (CHANGES)

[CHANGES]

OK. its seems that the wiring and sensors in that area have been changed..

The first thing to do is establish what is fitted and replace with the correct units..

The transducer has two terminals for two functions. one is for a pressure warning

light and the other for pressure gauge. Both wires are brown and white but they have

different size spade terminals so not to mix up. The earth is supplied through its mounting.

The Temp unit is positioned as indicated but does not look like the one in the last pic.  

That one looks more like a pressure switch. They have the same screw fitting but 

different function. Check you do not have the same problem.

Just a Guess here.... 

If your pressure gauge is working but no warning light or temp, you may have the situation

of the transducer fitted is for that only. Then if you also have a dysfunctional temp sensor

or a pressure switch fitted where the temp sensor should be as the pic. ( this would be to

replace the missing one on the transducer) this would explain the problem.

Your loose wire is brown and white so,  if you have a pressure switch fitted alternatively

in the temp sensor position then it is wired to the temp wire not the b/w wire so neither will work. 

I suggest the best option is to buy new OEM units and fit using the correct wiring configuration.

This will eradicate all errors in that area and go along way towards your overall solution.

Hope this helps.. 

[ramjet]

Also it looks like, on your picture John, that the spade connector has been cut off and replaced with one of those crimp-on fittings. I think you may be able to use that with a new sender as they have small bolts on the top though it will be an absolute bugger to do where it sits on the engine.

 

I would be looking to replace that with the correct size spade connector as well. The plastic covers on mine are actually different colours to each other as well to aid with identification I presume.

[J400GED]

John,

      The oil temp gauge sender should have one terminal on it and the pressure gauge sender has two terminals - one of which is for the low pressure warning light.

 

oil gauge wiring s4.doc

 

 

The wire you describe being Brown with White trace (labelled NW in the diagram) is for the low pressure warning light. The pressure gauge wire is White with Brown trace (labelled WN in the diagram). If your pressure gauge is working, the sender is working.

Your oil temp gauge sender should have a single terminal and the wire for this is Yellow with Black trace. Both senders are earthed through the block.

 

 

Again, does your low pressure warning light illuminate when you key on prior to starting the car?

 

 

 

Ged

[Techspy]

Ok guys, thanks for all the info. So, I have the wrong oil pressure sender fitted so it only has one terminal for the gauge and is missing the terminal for the idiot light which is why I have a disconnected wire. I will double check to see if the idiot light comes on with the rest during startup.

 

Completely unrelated, my oil temp gauge is not working. I checked and the wire is connected to the oil temp sensor. It doesn't seem very tight though so I will check it with the engine running to see if I get a reading. One strange thing is that the other day, when I had a bad injector and only running on 2 cylinders as I limped home, I noticed that as I would rev the engine, the oil temp gauge would go lower (past the zero reading). Maybe it has been doing that all the time but I only noticed it because I was paying close attention to all the gauges.

 

Well, it looks like nice weather today so I will get her out and do some testing.

 

Thanks again for all the help guys.

Edited March 3, 2013 by Techspy

[Techspy]

So the loose wire was the issue with the oil temp gauge. Its working now. I will replace the oil pressure sender so that the idiot light works.

 

Thanks again guys.