do you recognize this oil-related sensor?

[edb68ots]

Can anybody tell me what this sensor is? it's on my car right next to the oil filter head, it's not connected. Just curious if it could be a manual oil pressure sensor? Or some kind of low oil pressure sensor?

It appears to show, "ITALY 050", on one surface, and, "027 15F" on another.






Thanks in advance!

Ed

[bitsobrits]

Ed,

Don't know for sure what it is, but if you check it's resistance while cold, while at idle, and at some speed above idle (use a multimeter set on ohms, one lead to spade terminal, other to ground) you could determine from the values you see what it likely does.

As a guess, I would hazard it's an on/off switch of some sort-for a low pressure indication light or to turn off the fuel pump when the engine dies (as in an accident).

[christopher storey]

Almost certainly it is the oil pressure switch used ( usually on 4.2s) to power the alternator warning light !!

No, I am not joking ... on the early 4.2s at any rate, instead of using an electrical circuit measuring charge, wich extinguishies the alt warning light when charge is occurring , they simulated it by using the rise in oil pressure

[tinworm]

Absolutely never heard that before Chris.
I was going to suggest the switch was for a fuel pump cut off circuit (on zero oil pressure - after a crash) and therefore an addition. Or maybe an oil temperature gauge addition.

Barrie

[mgcjag]

Could be an oil oressure switch or an oil temp switch......as Christopher says S1 4.2 had an oil pressure switch that operated the red light in the speedo

[tinworm]

Thats new to me I must say.
I thought it was a combined warning lamp ie oil pressure and ignition warning (like the handbrake/brake fluid level) . Is that what you mean - and I am misunderstanding things? The early alternator equipped cars had the ammeter still too.

Barrie

[mgcjag]

always something that catches us out Barrie.......

[tinworm]

Had a chance to look into the wiring on this little mystery (to me that is) . The 3AW unit earths down the warning lamp when not supplied with current from the alternator (ie engine stopped fan belt missing etc) just as the oil pressure switch does (in the photo supplied by the OP). So both warnings do bring on the same warning lamp - but for different alarms and they are independent of each other. So-strange Jaguar should do this and I don't know why I have not noticed it before.

Barrie

[Tommd]

I believe there is some misunderstanding. The E Type does not have an alternator warning light. It has an ignition warning light. The ignition warning light is to warn the driver the ignition key is left on when the engine is not running. In early cars, including S1 4.2's up to about July 1967, the ignition light was controlled by an oil pressure switch. Key on, engine not running, no oil pressure, ignition warning light lit. (yes, if one knew how the Ignition warning light was wired, one would know that if the light lit going down the highway, the engine had lost oil pressure. But the gauge was for that.)
July 1967, the oil pressure switch was replaced by the 3AW control unit. Now the ignition warning light was controlled by the alternator. If no alternator output, the light would go on. Thus, key on, engine not running, no alternator output, ignition warning light lit. (Yes, if one knew how the light was controlled, when driving and the ignition warning light came on, one would know the alternator stopped charging, although the amp gauge was to monitor charging function.)
This was an either or. Early cars had the light controlled by the oil pressure switch. Later cars by the 3AW, but none by both. The wiring diagram just shows them both.
Tom

[christopher storey]

I believe there is some misunderstanding. The E Type does not have an alternator warning light. It has an ignition warning light.

They are really the same thing - it's just a question of terminology

[paydase]

Tom,
if I follow you, the ignition warning light below the speedometer is triggered by an oil pressure switch.
On both my FHC (1964) and my OTS (1961) I don't see where the switch would be.
Definitely not in one of the bolt holes of the oil gallery on the block.

I notice btw that I have never seen a red light even when an OP close to zero was indicated by the OP gauge
So missing or where else?

[mgcjag]

Hi Serge...have a look at the 3.8 wireing diagram in the service manual....3.8 cars have an ignition warning lamp connected to the control box......Steve

[Tommd]

Serge, sorry, I was only partially correct and thus misleading above. On the 3.8 S1 with generators, which is what you have, the ignition warning light is a generator charge light. Starting with the early S1 4.2 with the alternators, initially they used an oil pressure switch, then changed over to the 3AW.

Steve, I would not call it terminology on the early 4.2's. It is not connected to the alternator at all until later, then one could call it an alternator light.
Tom