Temp Gauge/Coolant Sensor (Long)

[OBEEWON]

S13 blacktop

I was having an issue with getting air in my coolant system earlier this summer. After replacing rad cap, flushing rad, and changing some hoses everything settled.

Prior to that I had an issue with the connector to the ECU/dash temp sensors. Sometimes it would jiggle lose and the car would start running super rich till I would tighten the connection. (When this happened the temp gauge would stop working, since they were on the same connector.)

Shortly after all this the gauge started acting really wierd. It would read super low temp, like barely above the bottom tick mark. Every day it read lower and lower but the car was clearly at norm temp.

That brings me to today. The gauge wont read at all. Its as if it slowly died. I have the connector secure, re-soldered the wiring for the CTS to the dash, and it wont even lift off the little needle.

The wierd thing is when I disconnect the plug that goes to the harness from the two CTS' the idle jumps up for a moment then goes back down. Same thing when I reconnect it.

Any help is greatly appreciated.


(Oh yeah, I bought an ECU CTS from Courtessy, but its the wrong one. So I didnt replace that yet)

[cotbu]

The 2wire ecu temp sensor will store a code in the ecu, if it's faulty. The single wire thermistor will not, but will cause the gauge to read crazy.

When you disconnected and reconnected the plug, more than likely the ecu temp sensor is triggering the ecu, and you should have a code stored.
That's telling me, it's working normally. Try disconnecting the thermistor from the sensor plug to see if your temp gauge changes. You're bound to hear get an aftermarket gauge at least twice. I would fix the problem first, because it could be a short in the harness. Check continuity on the dash to ecu connector then from ecu to thermistor. Then the resistance on thermistor against the FSM or thermometer (if you know the co-efficient). Probably overkill, just replace the thermal resistor.

[OBEEWON]

Thermistor is the one wire correct? Where do they sell the resistors.
Is there a trouble spot on the harness that usually shorts in this instance? Like back of the cluster or something?

It seems like my A/F isnt really affected with the sensor connected or not. It changes for a second but goes back. Plust my idle is high usually. (cammed, but still high for a cam)

[cotbu]

Correct, auto parts chains may carry, but Sheridan Nissan is were I would order mine, because I can show them exactly what I need.
Nissan calls it a thermal transmitter

How High is your idle, does it ever come down, can you make it go up or down by pinching a vacuum line?

[OBEEWON]

On average its about 1200, I can drop it down by putting it in gear and letting up on the clutch a little while on the brake. lowest is about 850 on average. Pinching vac line doesnt really change it that I can recall.

Do you know the part number for the S13 blacktop one? Is there a difference?

[adictd2b00st]

anyone know the part number for the s14 one? my gauge is going crazy too, i ordered one from napa but its the 2 prong guy, not the single

[OBEEWON]

Bump for part numbers.

[cotbu]

This is for a 95-99 sentra se-r 25080-89907
It may work or not, they suggested that, "I bring in my old thermistor to verify exactly..." HTH

Part Number 25080-89907

[OBEEWON]

Thanks man!!

[adictd2b00st]

http://www.courtesyparts.com/betasite/240sx-s14-1995-1998/genuine-nissan-parts/exhaust-cooling/210-water-pump-cooling-fan-thermostat/-c-3690_3691_3714_3716.html

dunno if that helps either, looks like the single wire one is the one on the left in that picture?