Temp Sensor ID Help

Rawknees'Turbo · 09-15-2016, 07:13 PM

On later 80's models there is what the PET IDs as "Temperature sensor" on the crankcase breather cover - it's different from the switch with the two, small vacuum NIPPLES that prevent timing advance when engine is cold (long since bypassed on my car); I'm wondering if any of youses know what the sensor is for. It's part number 93060611703 .

I ask, because I just noticed that mine was not hooked up - wire nearby by not attached, and lots of corrosion on it, so has not been on in a long time. I'm the only person that has worked on my car since about 2007, including engine out, so I must have left it off by accident. Is it something to do with an emissions solenoid? All of my emissions components are gone. Funny how after all this time, I still sometimes find components that I am clueless about.

Thanks.

icemann427 · 09-16-2016, 08:45 AM

Rawknees,

I believe it is a temperature sensor for fuel enrichment when the engine is cold. I easily could be wrong.

WERK I · WERK I's Garage

^^^ That or maybe part of the Lambda circuit on DME equipped 930's. Since cold starts are by nature rich, it might turn off Lambda adjustments until warmed up at idle.

heliolps2 · heliolps2's Garage

Hey guys, Yes it's designed for cold start, It limits vacuum to distributor, retards timing on cold and the once its warm then the timing advances,

Rawknees'Turbo · 09-16-2016, 12:48 PM

Helio, the switch I'm talking about is different than the one that limits vacuum to the distributor (this is not the one with the vac nips on it - which has been eliminated on my car) . . . the switch I'm asking about is on the breather cover, but on the opposite side and end of the vac switch, and it has a singe, male wire terminal on it.

Thanks for the input (not like THAT) though, guys. I plan to operate the car with it hooked back up and see if anything is different.

icemann427 · 01:28 PM

Oil temperature sensor for the oil temp gauge?

Ah, OK...

Rawknees'Turbo · 09-16-2016, 01:24 PM

Nope on oil temp - dat's near the fan, Icyhotness.

icemann427 · 09-16-2016, 01:37 PM

Thermoswitch for Fan - Late-Style Factory Oil Cooler, Part #: 930-606-118-00

pkabush · 09-16-2016, 01:59 PM

Ding, ding, ding. Do we Have a winner?
I looked around for a bit last night after u posted but the only thing that came up was the part f/s

Rawknees'Turbo · 09-16-2016, 02:11 PM

I still don't get it (not like THAT!). My car has the oil cooler fan switch installed on the front oil cooler (I noticed the similarity in part number when I looked at the PET last night).

Here it is on Pelican -

Pelican Parts - European Automotive Parts and Accessories - Porsche • BMW • Mercedes • Volkswagen • Audi • Saab • Volvo • MINI

Rawknees'Turbo · 09-16-2016, 02:20 PM

Did any of them actually come with the oil cooler fan switch mounted on the breather cover? Doesn't seem likely, but who knows. My car is jacked way up in back right now, so I can't get under there to verify that the fan switch is actually on the oil cooler, like most of them are . . .

icemann427 · 09-16-2016, 02:59 PM

I guess so. It appears to be on my engine when I did some work on it years ago.

Rawknees'Turbo · 10-01-2016, 02:09 PM

^^^

As a follow up to this tread (a very interesting thread, like the"hey, I'm pushing 700 hp" ones, I know!!!) - that is the sensor I'm talking about, Icyhotness (the one with the single, wire end on it), butt it is not for the front oil cooler fan (I verified this by grounding the wire that goes on that sensor, and the fan did not come one (I know that it works as I've witnessed it running) and was also able to see that the oil cooler on my 1987 has the fan temp switch screwed in to the top end (like is common).

Sooooooo, the purpose and function of that temp sensor is still unknown (at lest to me).

Speedy Squirrel · Speedy Squirrel's Garage

It is a temperature switch, not a temperature sensor. It switches at ~35C. It is connected to the larger under-seat box at Pin 11, with a green/yellow wire. it's purpose is to initiate closed loop control at near idle with the frequency control valve on 1986 to 1988 US 930's.

Rawknees'Turbo · 10-01-2016, 05:36 PM

Thanks Speed. It's funny how the Porsche calls that a "sensor" when it is actually a switch - not surprising though, as there are lots of errors like that in the PET and electronics were definitely not a strong suit in the 911 side of the factory.

So what does the closed loop control of the frequency valve at near idle actually do - is it meant to further lock in a near 14.6 idle AFR?

JFairman · 10-01-2016, 06:31 PM

I think it's the sensor for an engine temp idiot light.
The sensor that disables the lambda system in late eightees cars when the motor is cold is in the right side chain case cover.
Left side chain case has the thermal time switch for the cold start valve. It's tied in with the starter motor and has it's own thermal heater to disable the cold start valve so it doesn't flood the motor in case the car won't start while somebody keeps on trying over and over again and again.. until the battery is dead or the starter motor says see ya.

Speedy Squirrel · Speedy Squirrel's Garage

Quote:

Originally Posted by JFairman

I think it's the sensor for an engine temp idiot light.
The sensor that disables the lambda system in late eightees cars when the motor is cold is in the right side chain case cover.
Left side chain case has the thermal time switch for the cold start valve. It's tied in with the starter motor and has it's own thermal heater to disable the cold start valve so it doesn't flood the motor in case the car won't start while somebody keeps on trying over and over again and again.. until the battery is dead or the starter motor says see ya.

(Edited for the fifth time!)

The one on the right chain housing cover is a switch that opens at ~35C, and connects to the Fuel Enrichment Control unit with a Green/Yellow wire.

The one on the top (the subject of this post) is a switch that opens at ~15C, and connects to the Oxygen Sensor control unit via a Blue/Green wire.

One lets the engine run a little rich on start up to heat up the catalyst. The other one starts the O2 sensor control.

The oil pressure light gets it's signal from a sender (not a switch). It is that bigger thing screwed into the right side tensioner feed line.

The oil temperature sender is near that, but in the block, not the chain cover. It does the temperature light.

The thermo time switch controls the cold start valve. It is in the left side timing cover.

For cars with the fender mounted oil cooler, there is another oil temperature sender on that part that controls the fan for the oil cooler.

OK, I think that is it.

JFairman · 10-02-2016, 05:58 PM

The bigger thing or sending unit by the right side chain case oil line is the oil pressure gauge sending unit.
Other than that I just don't care anymore.... Trying to figure this worthless over engineered obsolete crap out is a total waste of time.

I've hated CIS from the very beginning and hate it even more today. And... I think I know how it works since I've rebuilt 4 miserable CIS fuel heads now.

The aluminum heads are 20 times easier to rebuild than the cast iron ones because they go together dry with a rubber diaphram. You should put a little motor oil on the multiple o-rings (that better be ethanol tolerant) so they slide and don't try to roll over themselves or tear while pressing the two halves together.

Speedy Squirrel · Speedy Squirrel's Garage

You have better things to do Jim. Leave this arcane crap to us nerds!

Quote:

Originally Posted by JFairman

The bigger thing or sending unit by the right side chain case oil line is the oil pressure gauge sending unit.
Other than that I just don't care anymore.... Trying to figure this worthless over engineered obsolete crap out is a total waste of time.

I've hated CIS from the very beginning and hate it even more today. And... I think I know how it works since I've rebuilt 4 miserable CIS fuel heads now.

The aluminum heads are 20 times easier to rebuild than the cast iron ones because they go together dry with a rubber diaphram. You should put a little motor oil on the multiple o-rings (that better be ethanol tolerant) so they slide and don't try to roll over themselves or tear while pressing the two halves together.

Rawknees'Turbo · 10-02-2016, 07:22 PM

Speedy, the switch on the breather cover connects to a green with yellow stripe wire (like you noted in post #14), not blue/green noted in the multi-edited post #17 of yours. But regardless of the wire color, and based on your description of what switch does, does that mean if the switch is disconnected, that the O2 control is disabled? Anyway, thanks for taking the time to post all the info in post #17 - really helps explain some of the fine details of these dinosaur machines.

Jim, I hear ya'! With the many layers of complexity of K-Jet w/Lambda control, coupled with the basically absurd overboost protection system, it's hard to believe that these engines ever run, or run for long!