erratic coolant temp readings
Thread Starter
Racer
Joined: Jul 2001
Posts: 393
Likes: 1
From: Houston TX
erratic coolant temp readings
I have been getting occaisional erratic digital temp readings, like it reads 180, 170, 60, LO, 130, 170, etc. changing every second or two. This is usually associated with a severe miss/stumble.
I just replaced the water pump ECT sensor with no effect.
Any ideas? Could I have damaged the sensor by overtightening? Could this be and ECM or general electrical fault?
Thanks for your help.
Jason
I just replaced the water pump ECT sensor with no effect.
Any ideas? Could I have damaged the sensor by overtightening? Could this be and ECM or general electrical fault?
Thanks for your help.
Jason
Heel & Toe
Joined: Sep 2002
Posts: 22
Likes: 0
From: Alvin Tx
Re: erratic coolant temp readings (jsaunde2)
Mine was doin' the same about 3 wks. ago. There is another coolant sensor on the passenger side head, right behind the oil dip tube. Replaced that and my problem went away.
Le Mans Master
Joined: Jan 2002
Posts: 5,556
Likes: 0
From: Jenison MI
Cruise-In VI Veteran
Cruise-In VII Veteran
St. Jude Donor '06
Re: erratic coolant temp readings (jsaunde2)
I just had mine fixed last week, it was doing the same thing. the temp sensor on the water pump was shorting out.. I beleave the one on the head is for the analog gage
[Modified by fsr402, 8:07 PM 10/17/2002]
[Modified by fsr402, 8:07 PM 10/17/2002]
Thread Starter
Racer
Joined: Jul 2001
Posts: 393
Likes: 1
From: Houston TX
Re: erratic coolant temp readings (fsr402)
Thanks for the help.
I am wary to replace the water pump sensor as I just replaced it and it didn't help the problem.
Maybe I'll just go ahead and replace both and hope it fixes my problem.
I'm kind of worried I have a more general fault as I jst replaced the sensor.
Jason
I am wary to replace the water pump sensor as I just replaced it and it didn't help the problem.
Maybe I'll just go ahead and replace both and hope it fixes my problem.
I'm kind of worried I have a more general fault as I jst replaced the sensor.
Jason
Racer
Joined: Jul 2002
Posts: 412
Likes: 0
From: corvallis or
Re: erratic coolant temp readings (jsaunde2)
Dit you replace the wiring pigtail with the sensor? I run into this alll the time on GM products crappy connection to the sensor due to wiring breaking down.
Racer
Joined: Oct 2001
Posts: 444
Likes: 0
Re: erratic coolant temp readings (jefft84)
the problem lies in either the water pump sensor or the pigtail wiring harness going to it...I also had this problem for a while ..The sensor on the head is for the needle gauge on the dash and would have no affect on the digital readout..
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Le Mans Master
Joined: Jul 2002
Posts: 5,818
Likes: 2
From: Alive and well in Burlington NC
Re: erratic coolant temp readings (PeteL)
Could be a lot of air in the system.
Air bubbles passing the sensors could cause some very erratic readings. Burp the system (remove all the air) and keep the tank full.
Thread Starter
Racer
Joined: Jul 2001
Posts: 393
Likes: 1
From: Houston TX
Re: erratic coolant temp readings (jefft84)
I did not replace anything past the plug. That is likely the problem as I had to replace it because I broke the plug on the sensor side.
How would I replaxce this? do I just have to splice in a new plug?
Also, How would I "burp" the system? I bled all of the air out of the bleed screw like always.
Jason
How would I replaxce this? do I just have to splice in a new plug?
Also, How would I "burp" the system? I bled all of the air out of the bleed screw like always.
Jason
