Valve next to front vacuum port?
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Yup - coolant temp sensor. Two wires running to the sensor are yellow and black.
There is also a spot there that you can see avl to be tapped into. On the JS intake this is where I put my hose line from the back of the water pump that used to go to the thermostat housing x-over tube - before I cut it off and modded it to be shorter.
There is also a spot there that you can see avl to be tapped into. On the JS intake this is where I put my hose line from the back of the water pump that used to go to the thermostat housing x-over tube - before I cut it off and modded it to be shorter.
Whoa dude...thats wierd. I have my CTS in that spot...with the yelow and black wires. That seems odd...u have a sensor on the front of the intake below the thermostat housing right ? Has a single green wire with a connector attached to the sensor ?
Thats your idiot light 'TEMP' on the dash. Over temp light - telling you to pull the hell over and shut off the car. But the other sensor - where your valve is located - actually tells the ECM what the temp of your coolant is...I have an Autometer temp guage hooked to the one with the single green wire....and the other is my CTS.
Seems to be there's gotta be a yellow and black wire buried somewhere in the harness...unless it was forgotten - but thats doubtful. Id remove that valve and screw in a CTS then get it hooked up to the ECM somehow if u cant find the wires in the harness. Heres a pic of both of mine for you. You can see the CTS on the right side of the screen and the other sensor at the front of the intake that my Autometer guage is hooked to.
Thats your idiot light 'TEMP' on the dash. Over temp light - telling you to pull the hell over and shut off the car. But the other sensor - where your valve is located - actually tells the ECM what the temp of your coolant is...I have an Autometer temp guage hooked to the one with the single green wire....and the other is my CTS.
Seems to be there's gotta be a yellow and black wire buried somewhere in the harness...unless it was forgotten - but thats doubtful. Id remove that valve and screw in a CTS then get it hooked up to the ECM somehow if u cant find the wires in the harness. Heres a pic of both of mine for you. You can see the CTS on the right side of the screen and the other sensor at the front of the intake that my Autometer guage is hooked to.
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84ttype, the sensor in your pic is the original style that came on '84s. It is the same style plug as the knock sensor (so look for a plug of that type; or wires if plug was cut or broken off). In '85 they were changed over to the coolant temp sensor that is used on just about every GM after that (part #su109 at Auto Zone). I remember purchasing one a long time ago and it came with the pig tails/plug so that you can splice to your wires for the change.
My question is, is this a running engine?? Our ignition systems need the cts signal to be able to start up and run. The other switch [not sensor], as HOTSIX pointed out is just for the idiot light and is not critical. Thats the one that could be removed and replaced with a sending unit for a gauge. The cts that you have disconnected IS needed.
My question is, is this a running engine?? Our ignition systems need the cts signal to be able to start up and run. The other switch [not sensor], as HOTSIX pointed out is just for the idiot light and is not critical. Thats the one that could be removed and replaced with a sending unit for a gauge. The cts that you have disconnected IS needed.
All right then. Looks I'll need to get this from caspers Hi Temp Splice and then rip my harness apart and look for those wires. The thing I don't get though is that it says the sensor is located under the linkage?
Not sure if thats the right plug or not. Thought it was supposed to be a 2wire. Besides, why not just go to the parts store and get the updated sensor w/ plug for $10. OR..... you could go to the junkyard and get the sensor and plug for FREE84ttype said:
Theyre on 3800s, 307s, chevy motors, etc, etc.Here is what troubles me, I tore the harness apart and narrowed it down to one of two yellow wires on the harness(I actually found four but two splice into one bigger gauged wire) but the thing is neither is cut. I'm assuming the wires come out of the harness at the same place the connector for the coil pak and the cam sensor come out right? I can say that this car was running before, And I don't remember removing a plug like the knock sensor from the front.
That Hi-temp Splice you linked is not correct.
I dont have one on my car. Thats gotta be for some other application or is a bad pic or link. I dont have a connector similar to the knock sensor on the front or back of my block either. Just the knock sensor.
The sensor is the same as in my pic above - a 2 wire yellow and a black. Its a female plug on the harness end.
Sounds like you have a doctored harness. Maybe call John at caspers - they are always willing to help you out. The sensor wiring on mine comes outta the harness where the coil pack is.
Best bet - trace the wiring and see what ur missing or what goes where. Big job but you'll find those 2 wires eventually.
I dont have one on my car. Thats gotta be for some other application or is a bad pic or link. I dont have a connector similar to the knock sensor on the front or back of my block either. Just the knock sensor.
The sensor is the same as in my pic above - a 2 wire yellow and a black. Its a female plug on the harness end.
Sounds like you have a doctored harness. Maybe call John at caspers - they are always willing to help you out. The sensor wiring on mine comes outta the harness where the coil pack is.
Best bet - trace the wiring and see what ur missing or what goes where. Big job but you'll find those 2 wires eventually.
I think 6sense pointed out that the 85 cars had a different temp sensor than the 84s. I found that plug at caspers as well and I can tell that it won't fit the sensor on mine only has one "prong", yours has two. But I plan on upgrading to the newer style one. thanks for your advice though, I'm pretty sure I am going to have to rip my harness apart now.
Well I finally got my engine harness apart and what so I find? how about two black wires spliced into one. One of which comes from the TPS, one wire found! and two yellow wires spliced into one with a hot engine switch spliced into that. found wire #2! It looks like the way the guy had it set up before me was instead of sending the signal to the ignition system it was spliced into the idiot light circuit. So this proves that my car was running with out the sensor, so I guess being spliced into the idiot light circuit allowed it to start and run?? 
Yup. Sounds about right.
Sorry missed the line about the 84's having a different sensor than the 85's.
If you are upgrading to the 87 ECM though in the future it would be wise to switch to the 2 wire sensor.
Just do like I did - rip apart the whole harness...figure out all the wires and good - and their locations - then buy a few rolls of tape and wire loom - do it all back to factory again. Its the little things that keep me sane on the car that I know are done right !
Sorry missed the line about the 84's having a different sensor than the 85's.
If you are upgrading to the 87 ECM though in the future it would be wise to switch to the 2 wire sensor.
Just do like I did - rip apart the whole harness...figure out all the wires and good - and their locations - then buy a few rolls of tape and wire loom - do it all back to factory again. Its the little things that keep me sane on the car that I know are done right !
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