Temp sensor went crazy on my engine
Thread Starter
8th Gear
Joined: Sep 2003
Posts: 8
Likes: 0
From: Allentown PA
Temp sensor went crazy on my engine
Last year I replaced the optispark due to a leaking water pump. The only casualty was the temp sensor on the water pump, the plastic end broke and would not make good contact with the plug. No problem changed the sensor. But the sensor must have went a few weeks later and my check engine light came on. No engine running problem just starting when hot have to hold the pedal to the floor to start. However, when running hard, full throttle high rpms and speed, the AC would blow hot air. Strange. So after a few more runs like that and checking the gauges I notice the AC would switch to hot are when the digital water temp went to 32 deg or too low indication? Very strange because my anolog gauge read approx 190 F.
Changed the temp sensor again and the engine went nuts, barely ran, stalling on any type of acceleration, kicked and bucked like heck. So un plug the sensor and runs like it did before, problem starting when hot but otherwise fine. Now I need to get my emissions sticker and I do not think they will pass it with an engine light indicator. The code before puting in the latest sensor was P0118 Engine Coolant Temp Circuit High Input.
Don't know what to do except try another sensor but there must be more than one based upon digital read out and the anolog gauge. Any advise
Changed the temp sensor again and the engine went nuts, barely ran, stalling on any type of acceleration, kicked and bucked like heck. So un plug the sensor and runs like it did before, problem starting when hot but otherwise fine. Now I need to get my emissions sticker and I do not think they will pass it with an engine light indicator. The code before puting in the latest sensor was P0118 Engine Coolant Temp Circuit High Input.
Don't know what to do except try another sensor but there must be more than one based upon digital read out and the anolog gauge. Any advise
Le Mans Master
Joined: May 2005
Posts: 7,354
Likes: 2,278
From: Central Maryland
There are separate sensors for the analog gauge and the ECM. The analog gauge's sensor is in a cylinder head (passenger's side, if I recall correctly). The one in the water pump feeds the ECM.
If the car is not overheating, and the reading you're seeing on the analog gauge is realistic, there's definitely a problem with the ECM's sensor, or the wiring to/from it, or a problem with the sensor's ability to make a good ground contact to the water pump.
Did you install the sensor dry, or put a thread sealant or teflon tape on the threads?
Remove the connector from the ECM's sensor, and carefully examine the contacts for signs of a corroded/sprung/bent/broken/missing contact, etc.
Be well,
SJW
If the car is not overheating, and the reading you're seeing on the analog gauge is realistic, there's definitely a problem with the ECM's sensor, or the wiring to/from it, or a problem with the sensor's ability to make a good ground contact to the water pump.
Did you install the sensor dry, or put a thread sealant or teflon tape on the threads?
Remove the connector from the ECM's sensor, and carefully examine the contacts for signs of a corroded/sprung/bent/broken/missing contact, etc.
Be well,
SJW
