3SGTE cold start timer switch resistance readings

My 1992 SW20 3SGTE has needed a bit too much cranking lately to get it started so I checked the resistance readings of the cold start timer sensor. When cold, my sensor is about 72 ohms from terminal STA to ground (the red/white wire that supplies +12V). This agrees with the BGB.
STJ to STA reads about 74 ohms which also agrees with the BGB. What is strange though is that the BGB doesn't give a reading for STJ to ground. They must assume that everyone knows that it should read near zero ohms to chassis? Mine reads about 140 ohms to chassis for STJ which I reckon means the sensor is stuffed and the cold injector never gets turned on.
With the sensor disconnected,I connected the green wire in the connector (STJ) to chassis and the engine started OK within about half a second. Has someone got a resistance reading of a good sensor's STJ terminal to chassis?
Thanks, Mark

I ended up buying a new switch (89462 20020) and just fitting it. I got a quote from my local Toyota spare parts of $327.00.
I then proceeded to purchase the switch from Amayama Trading Co. in Japan. The brand new part sent from japan cost me $126.60. I had to wait about a week to receive it,but who's going to complain when you're saving so much money? I reckon it was good service.
With the new switch fitted, I haven't needed any prolonged cranking at any engine temperature so it was obviously my problem. The resistance readings were inconclusive,the same on the new switch as the old switch. I wasn't going to mess about with a brand new switch, so I didn't get to the bottom of the problem with the old switch. Why does it have to be a "timer" anyway? Maybe it's to restict too much fuel flooding the engine if it doesn't start for some other reason?

MRTurbo

Good work, looks like getting it in and out would be a pain though?
Most people wrongly assume that its the cold start injector thats broken if their car doesnt cold start properly.

 
Replacing it was fairly straightforward.
1. Remove strut to chassis cross brace.
2. Reomove the two hoses in front of cold start timer switch that are in the way.
3. Unplug the connectors from ECU coolant temperature sender and cold start timer switch.
4. Unplug the oil pressure sender.
5. Slip a 22mm. tube spanner over the cold start timer switch and loosen it. I put a closely fitting steel bar in one of the holes on the side of the tube spanner for leverage.
6. Have the new switch ready to install and swap over quickly so not too much coolant leaks out.
7. Put everything back the way it was.
8. Top up coolant.
Be careful when moving the new switch towards the threaded hole so that the new copper washer that comes with the switch doesn't slip off and fall down. Mine fell off so I quickly put the old copper washer on the switch and installed it so I didn't lose much coolant. I retrieved the new washer afterwards.
I also haven't had any problem with air in the coolant causing overheating,so all seems good.

It's a Gen 2.
 

bigh

grunt, what gen mr2 did u have?