temp sensor - Toyota Nation Forum : Toyota Car and Truck Forums

kevin · 05-28-2003, 08:06 PM

does anyone know witch one of the coolent temp sensors feeds the ecu?is it the one on the left hand side next to the power steering brace,or is it the one on top?

cdnsupra · 05-29-2003, 02:34 PM

are you refering to mk3 supras? 86.5 - 92?
if not, which years/models?

kevin · 05-29-2003, 04:15 PM

yes,its an 87 turbo.

cdnsupra · 05-30-2003, 12:36 PM

there are several sensors attached to the water thermostat housing. there are 2 single wire leads. the one in front of the thermostat tells the cold start injector when to fire and when to kill the higher idles. the one behind the thermo tells the temp gauge what to show.

does that help?

kevin · 05-30-2003, 05:32 PM

yes,thank you.my supra is still surging at idle and i was told that a bad coolant temp sensor would cause it to surge.so i assume the sensor that runs to the ecu would be the one to change?

cdnsupra · 06-05-2003, 11:39 AM

i have had my 87 since 88. my 91 for 3 years now, and my bro had an 89 for a few years. i have only seen one of those sensors go bad, but it did not cause aa surging idle. that sounds strange to me.

does it only surge while idling?
i would look at other things like an air intake leak, bad fuel injector, bad plugs or wires. tuneup things.

kevin · 06-05-2003, 04:43 PM

yes it only surged at idle,when giving throtle it would stop.but i fixed that the isc motor was bad.then it would idle at 500 rpm. so i finally gave up and took it to the toyota dealer in my town and they told me the maf sensor was bad and the tps was bad.i changed the tps first but the auto parts store gave me the wronge one.so back to square one ,the tps.thanks for the help

cdnsupra · 06-06-2003, 07:20 AM

when the maf(Air LFow Meter) sensor goes, the engine will start, and idle, but if you give it gas, it will die. that is the typical way you can tell. the AFM also puts a code in the ecu that you can check.

do you have an orange engine light on the dash, and did you check what the codes were?

maybe the combination of the tps and afm together give you the erratic idle.

kevin · 06-06-2003, 08:34 PM

the car was giving a code 31 for the maf.a friend has an 87 turbo also so we swaped maf sensors and put a new tps on and it fixed the problem.so now i need to find a maf and i'll be done.thanks for the help!