Does the Cylinder Head Temperature Sensor send info to the ECU to control performance of the engine, or does it soley control just the Temp Gauge? Also, when checking Kragen, they didn't have it under the name of Cylinder Head Temperature Sensor, but they did have a Coolant Temperature Sensor. Is the Coolant Temperature Sensor used at three places in the car? Top/Left of Radiator, Bottom/Right of Radiator, and on the Cylinder Head?

Thanks,
zellix

 

The CHTS has nothing to do with the coolant temperature. It actually measures the temperature of the heads itself. It's used as a factor for the air/fuel mixture for the car for optimal performance. If that goes bad, it can cause your car to run overly rich or lean. If that's bad, you'll need to replace it.

S

 

Is it a rare item or does it have a secret name? Because I've been looking around and no local auto shops carry a sensor by that name.

 

You will probably have to go to the dealer for it. You may need the wiring harness that goes to it also. It's usually corroded and/or broken, and not reusable.

 

Check out some places like carparts.com, or NAPA auto parts. They should have something there. The Shucks/Kragen/Checker stores don't always down to specific parts like they do.

S

 

Well I did alittle looking around, and went to carparts.com (thanks maximase86) and under the CHTS, it gave a part number which I then searched kragen.com for. Turns out the CHTS IS a coolant sensor, which makes sense, since when I pulled the CHTS out of the car, there was coolant right behind it. So I guess there really are three coolant sensors.

 

Are you sure you're looking at the right sensor? The CHTS is in the front head on the passenger side, tucked in behind the timing belt cover. It pretty hard to get at without some disassembly. There shouldn't be any coolant behind it. It just screws into a blind hole as far as I know. There ARE two coolant sensors on the intake manifold.

 

Yeah, sounds like you have the wrong sensor, this maybe a dealer thing to look for....though its wierd that carparts.com has it listed as a coolant sensor.

S

 

it sounds like you got the water temperature sending unit (nissan calls this the thermal transmitter), this is the sensor for the temperature gauge on the dashboard. this is screwed into the block to the rear (firewall side) of the engine, near the PCV valve.

the other temperature sensors are mounted inside the radiator, for the cooling fans.

the cylinder head temperature sensor, like pkfinn said, is located near the water pump, and has a long wire harness coming from it. it will be impossible to replace this unless you disassemble the whole side of the engine, down to the timing gear cover. I know from experience because when I replaced the timing belt, the wires kept getting in my way. It's really easy to find this, I think it's the only set of wires running near the thermostat housing.

Dan
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1988 Nissan Maxima SE, black, 5-speed
down temporarily.

 

Ah, that makes sense, since my Temp Gauge isnt working. Been trying to find which sensor controlled that, thanks Too bad I still need to find that CHTS and check it, it's the only error coming up on my Mode3 ECU Self-Test. I guess if I'm extremely lucky (which I'm not to often with this car) it's just a bad connection that needs a little cleaning or repairing, and not the CHTS itself. Thanks again.

zellix

 

The CHTS and it's sub harness are prone to corrosion. It's in a hard to get to location, but you may be able to clean the terminals on the sensor and remove the sub harness for cleaning or replacement. The sensor should read approx. 2.3 - 2.7k ohms at 68 degrees F. At 122 degrees F. it should read 0.77 - 0.87k ohms, and at 176 degrees F. it should read 0.30 - 0.33k ohms. You should be able to disconnect the sub harness from the main harness and check it there first. If it doesn't check out, then you can disconnect the sub harness from the sensor and inspect it.

Good luck, and let us know what you find.

 

Well went out a checked the connection with a Ohm meter to see if I was gettin any of those readings, well, I got an open circuit. So I'm definitely suspecting the wiring harness is more likely defunt, rather than the CHTS. So tomorrow, I'm gonna test the sensor by attaching two long needles to the meter and hitting the sensor prongs, which should give me a closed circuit reading since its a thermistor. But as things are running now, it all makes sense. If I understand correctly, my sensor or lack thereof is sending a signal that my motor is cold, therefor giving my engine more gas the whole drive which would cause a large decrease of power when running at higher temperatures and would give me horrible gas mileage (8-13mpg). Not to mention the ECU code. One thing I'm still confused about is, would that affect my timing very dramatically? I set it to 0BTDC mechanically and ran the engine which ran at 10BTDC when using the light, but after pulling it out of the driveway to see how it would perform, I knew it wasnt gonna go anywhere fast. Checked timing again and it was at -15BTDC... after letting it run alittle longer it was, 35BTDC. So I'm almost thinking the distributor gear is screwed up somehow. Guess that will all be a mute point if the CHTS fixes it.