15C temp switch for CIS - necessary?
 

During the troubleshooting of my CIS I discovered that the 15C temp switch on the timing chain cover was faulty (doesn't seem to close at any temp). As I understand it, this switch turns on lamda control when the temp gets above 15C. I look at the price of a new sensor (~$130!) and I wonder if it is necessary. Currently, I have just grounded the wire normally connected to that switch so the system is always under lamda control. I will have to wait until fall/winter here to see if there is any difference starting/idling the car when the temp is <15C.

Is this just another ancillary emissions device like the decel valve? Even for an engine starting at 0C, it would probably take <2min for the oil to warm above 15C, I would think.

Thanks.

Geoff

In that two minutes it takes to warm up the oil the engine is running in a very lean condition which can result in a very costly intake repair.

You can probably find a used thermoswitch if you ask in the wanted parts forum for less than $25.

Ok. I thought it might be one of those things that served only to reduce HC emissions during warmup.

I posted for on in parts wanted. Thanks.

Geoff

Geoff,

I have an 82 as well.

I thought the 15C temp switch was the one on the breather cover on the front of the engine? I'd have to look at the Bentley to be sure though.

If I got it wrong, can you remind me what the breather switch is called? I think that they only came on the 82 and 83 SCs.

According to Bentley, the one on the crankcase vent is a 35C switch, the one on the cam chain cover is the 15C one. Actually, looking at my build photos they look pretty similar - is it possible that I mixed them up during the rebuild (hence the 15C one not closing at 15C)?

Geoff