ok -
1990 v6
so I'm troubleshooting my truck's engine problems. Runs rich, idles high, stumbles at times, fouls plugs, gets crummy gas mileage, particularly in cold weather.
I've followed the fsm instructions to test my airflow meter, and find its resistance values to be within specs.
Now I'm trying to test the cold start injector time switch, and the coolant temperature sensor. I have specs to compare to, but I'm having trouble identifying the sensors - the diagrams from the fsm don't seem to match my engine.



This photo is looking down at the back of the engine. top of photo is firewall. Right is driver's side, left is passenger.
There seem to be 5 sensors in this array. The ones that are most obvious are the large green one, then the large black one to left. Left of the black one is another sensor (in shadow), and down to the left of THAT one is another. There is also a sensor down and to the right from the green one.

So I'll start from bottom right and go in sequence to 'label' them:
#1 (bottom right)
Green
Black
#4
#5 (bottom left)

This location is an real pain to get to - dang and blast those engin-eers. I'd appreciate any help in identifying these sensors. Yes, I'm looking for the C.S.I time switch and the C.T.S, but if you know identities of the other sensors, too, I'd be interested to know.
Thanks very much!
Scotty

Right off the hop I'd zero in on the O2 sensor.

Have you tried pulling the trouble codes from the ecu?