71T Where is the *$%#@ Idiot light sender?? :)

[Sam 69 Gulf]

Sorry – I know this is an over posted question but after reading all the posts I am still in the dark.
At the back of my engine, but accessible from the bay, is a pressure sender. Is this in the wrong hole or is this the correct location? I guess I could pull the wire and see if the pressure gauge dies when i get home.....

If this is in the right location where is the idiot light sender? Does someone have a nice pic to idiot proof it for me??

Thanks
Sam

[BlueSideUp]

[Gogar]

Oil pressure sender:



Down by the fan and the right-bank chain cover?

[porsche930dude]

Blue side i thought that was the oil temperature? Maby it is on my sc?

[rusnak]

there are 3 sending units, or sensors:

idiot oil pressure light sender: this is the one that you are pointing to, next to the crancase breather tube and the oil cooler thermostat.

oil pressure sensor: located at the rear of the engine near the crank pulley

oil temp sensor: near the pressure sensor.

I'll try to post a picture, but you can also refer to the exploded view parts diagrams locate elsewhere on this website.

[BlueSideUp]

I thought the same thing before I bought my car. The later cars have the oil pressure sender to the passenger's side of the fan. On the early models the temp sender is in the breather cap (you can see it in this pic) and the oil pressure sender goes into the hole behind the green wire in my photo.

[Sam 69 Gulf]

Thank you Rusnak – very helpful.
I currently have a pressure sensor (as in post # 3) in the hole designated for idiot switch in your diagram.
Mind you - when I bought this the plugs were finger tight and the leads on the wrong plugs (#4 & #5)
At least I am finding these now and it explains why the idiot light doesn’t work!
Sam

p.s. 4 responses in 10 minutes. I love this forum - I'd hug y'all if you were here for the trouble you have saved me!!!

[Sam 69 Gulf]

Uh - oh. hold my last post!
Blue side up - So my pressure sender maybe in the right hole. Where does the idiot light sender go? Where you originally said? (sorry - i didn't see your arrow until now)

[Sam 69 Gulf]

I wonder why previous posts confused me Those Germans - playing musical senders!

[Gogar]

IDIOT LIGHT Sender by "Blue Side Up"'s green wire.

PRESSURE SENSOR, like post #3 right near the passenger side of the fan housing and the passenger-side chain cover.

OIL TEMP sensor, by the oil pressure sensor and the passenger-side chain cover.

Blue Side up, I don't think the thing in the Breather cover is the OIL temp sensor, if you read the diagram Rusnak posted. Sam won't find anything like it on his engine.

[Sam 69 Gulf]

My temp sensor is where BSU indicates the idiot sender.
I dont have anything in the breather
I dont have anything near the passenger side of the fan housing.
My head hurts
I will pull the wire from the pressure sensor currently mounted near the breather and see what happens!

[rusnak]

if you have the 71 2.2 liter crankcase, here's the exploded parts diagram.

http://www.pelicanparts.com/PartsLookup/HTML/SubCat/911_USA_70_73_KATALOG.htm#
click "Engine/ crankcase" and you'll go to the parts diagram


here's a head hurter for ya though, part #59 oil pressure sensor is shown in two locations....

on the other hand, the location of the idiot light sensor seems to be resolved

[Sam 69 Gulf]

Still confused. The parts diagram shows my pressure switch correct but I am still no clearer where the idiot switch goes. As I cannot see it I will assume it is not accesible from the engine bay??

[Gogar]

Sam,

Here's my 2.4. Oil temp sensor right at the base of the fan housing/support, that your engine # is stamped on. Just to the right of it, at the base of the cam oil line, the pressure sensor.

Pressure wire is GRN/RED, temp sensor is GRN/BLK.

Sorry about the camera phone pic.




Edit: Of course, like the rest of us, I may be completely wrong if there's some diff between '71 and '72/73.

[rusnak]

the oil pressure switch **should** be the idiot light switch. It is an on/off switch hence the application to the idiot light. it should come on when you turn on the key, and switch off when the engine oil pressurizes.

The pressure senser is the bell shaped sensor, and the temp sensor....is ah, I don't know where it is on your car.

[rusnak]

ok there you go, Gogar shows where the oil temp sensor goes (not idiot light switch).

Pressure sensor right next to it.....idiot light switch then must be on top next to the breather tube fitting.

[Sam 69 Gulf]

Thank you all very much...buuuuutttt. Nothing so far has represented the combination of current senders, or even available holes, in my car. I will take pics of each existing sender openings and parts and post later.
Meanwhile I wil forget the light and keep an eye on the gauge!!
Thanks again
Sam

[rusnak]

sam

think of the idiot light sending unit as a switch.

The oil pressure as a sensor,

oil temp as a sensor.

pics would help. are we having fun yet?

[Sam 69 Gulf]

Got it. I understand how the switch can have one wire but was confused to see the (variable resistance) pressure switch and temp senders only have one wire too. I assume they must ground through the case? I would have thunk this woud give eroneous results.... (spoken like an ME, not EE - mind you as they used to say in school. You can't spell geek without a EE! )
It is a good job I love this car. At times like this it stops me putting am match to it!

[RWebb]

such a simple thing and so complicated...

It gets complicated 'cuz Porsche moved these things to different locations at different times - also there are other oil temp. sensors or switches - e.g. item #40 in the 3.2L diagram above (controls the blower fan maybe). And IIRC, there was some sort of temp. switch on some MFI cars(?)

I -think- they used to have the oil press. sender up on top of the motor. Later, it migrated down to the chain housing area. I don't know if there is any difference in oil pressure between the two locations (does anybody know??) - or if fluctuations are more prominent at one location or the other.

At one time, either Porsche or maybe only VW had a dual pressure can - it had a switch and a sensor in the same big can.

Anyway, be sure to check the wire colors on any sensor looking thing you see.