? help identify 4 sensors near injectors?
 

hi: i'm trying to understand what each of the four sensors are and do that are in the attached 2 photos.

the back story is that i had a bugger of a time getting my 87 xj6 to start during the fall and winter in michigan. the car would crank but not start. i even tried priming the fuel line by placing the car in gear then turning the key to start so as to engage the fuel pump 9this procedure worked maybe 5% of the time). so i went to the salvage yard last fall and grabbed the sensor nearest to the firewall, i left the second sensor (don't know why) and took the third and fourth sensors on either side of the coil. i swapped each one separately, during the fall and winter, to see if the car would cold start. there was no change. i recently returned to the yard to scrounge other parts and realized i had missed taking the second closest to the firewall sensor. i swapped it out the other day and the car has started within 3-5 seconds of cranking every time since. it has been 50ish in michigan since i swapped the sensor so maybe the engine and its internal fluids didn't get cold enough to give me problems.

sorry for the ramble.

Attachment 224357
Attachment 224358
Attachment 224359
this is the second closest to the firewall sensor. since i swapped it out, the car has started nicely every time including this morning when it was in the mid-forties. previously, i would have had a bugger of a time starting the car at this temperature.

as always, i appreciate any input that the learned members of this forum can provide. thanks, ren

The one you replaced is the CTS-Coolant Temperature Sensor. Plays a key role in cold starting, as the computer richens the mixture when the CTS signals that the engine is cold.

The forward most device is the Thermotime Switch. It controls the CSI-Cold Start Injector. The CSI gives an initial squirt of raw fuel for 0-8 seconds, depending on coolant temperature.

Next is the temp sensor/sender for the dashboard

Next is the CTS that you just replaced

Rearmost is the [can't remember the name] switch that serves several functions in concert with the Air Switching Module. This includes operating the diverter valve on the Air Injection Pump and other things that I might remember on my third cup of coffee

Cheers
DD

thanks doug. you've enriched my knowledge once again.