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  #1  
Old January 23rd, 2004, 07:58
Angus Angus is offline
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Temp sender/ engine coolant sender, same thing?

Looking for a motorhead here. I put my 2000 4.0 on a scanner yesterday and noticed something funny. The temp gauge read normal 210F, but the engine coolant temp for the PCM never went above 90F? I know the coolant was up to temp, so the gauge is close. My concern is the computer not getting the correct temp and running in open loop warmup mode. Are there two seperate senders or just one that may not be working perfectly?

Thanks, Angus
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Old January 23rd, 2004, 09:32
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90red 90red is offline
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Re: Temp sender/ engine coolant sender, same thing?

They are 2 different things. On my 90, the Temp sender is located at the rear drivers side of the head. It sends the temp to the gauges in your dash (or dummy lights). Your 2000 may have something different, but still serves the same purpose. The Coolant Temp Sensor is located on the drivers side on the block just above oil pan. It is what sends info to the computer. I would think the sensor is out if it is sending 90 degree readings when the temp is actually at 210. You can get them at NAPA for about $30 (or dealer, for more $$).

90red
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Old January 23rd, 2004, 13:07
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Wayne Sihler Wayne Sihler is offline
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Re: Temp sender/ engine coolant sender, same thing?

The sensor for the temp guage(located at the back of the head)and the Engine Coolant sensor(located in the T-stat housing) are two different things.
The sensor in the T-stat housing is connected to the PCM,on later models(98 on)this sensor supplys both the guage and the PCM with info.
Are you sure that what you saw was the temp reading for the coolant or was it the temp for the intake air temp ?
Wayne
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Old January 23rd, 2004, 13:11
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90red 90red is offline
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Re: Temp sender/ engine coolant sender, same thing?

Please ignore my previous post, I am not familiar enough with the newer XJ's to know the differences. The last thing I want to do is give someone the wrong information. Sorry guys, next time I will make sure I understand the workings of the vehicle.

90red
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Old January 23rd, 2004, 13:20
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Wayne Sihler Wayne Sihler is offline
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Re: Temp sender/ engine coolant sender, same thing?

Quote:
Originally Posted by 90red
Please ignore my previous post, I am not familiar enough with the newer XJ's to know the differences. The last thing I want to do is give someone the wrong information. Sorry guys, next time I will make sure I understand the workings of the vehicle.

90red
I know what your saying.Have 3 XJs in the driveway(87.96.98) and they are all different,It,s like there from different MFG,s
Wayne
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  #6  
Old January 23rd, 2004, 16:39
Angus Angus is offline
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Re: Temp sender/ engine coolant sender, same thing?

My parts book indicated that there is just one, but I was checking. When I scaned the truck I checked the parameter to make sure what I was seeing. The air intake temp and water temp are seperate. In fact my scanner has the ability to read several different "temps" around the motor. I did not know if anyone has run into this or not. Something that may have cause "wear" on the sensor is my factory block heater. When plugged in the coolant can be heard bubbling. Well it was an idea anyway.

Angus
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  #7  
Old March 29th, 2004, 07:29
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geepers geepers is offline
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Re: Temp sender/ engine coolant sender, same thing?

Quote:
Originally Posted by Wayne Sihler
The sensor for the temp guage(located at the back of the head)and the Engine Coolant sensor(located in the T-stat housing) are two different things.
The sensor in the T-stat housing is connected to the PCM,on later models(98 on)this sensor supplys both the guage and the PCM with info.
Are you sure that what you saw was the temp reading for the coolant or was it the temp for the intake air temp ?
Wayne
Hello All,
Reading this thread I may have stumbled onto something !! I have been having start problems in cold weather with my 92 XJ 4.0I6 .. I have replaced every sensor along with rebuilding my NSS. Still when the weather drops below 32 degrees I experience a no start condition , after turning the key on and off several times she attempts to start but floods out and by holding the peddel to the floor to blow out injectors and a cloud of blue smoke she will run all day with no problems .. Q: ? Could this be linked to my T-stat in my housing is faulty sending no signal to the pcm ?? I don't believe it has ever been changed 166,000 miles ...
Thanks in advance for you input

geepers
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Old March 29th, 2004, 10:24
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Re: Temp sender/ engine coolant sender, same thing?

I believe on the newest (OBD-II) models they eliminated the temp sender in the head and the dash gauge now receives data from the main data bus and the PCM. It's my understanding that beginning in '96 there is only one temp sender, the one in the t-stat housing.

If that's correct, though, I don't understand how the same sender could be delivering two readings that differ by more than 100 degrees.
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  #9  
Old March 29th, 2004, 11:59
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RichP RichP is offline
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Re: Temp sender/ engine coolant sender, same thing?

Maybe the 90 is a percentage reading and 0 equals cold - 100 equals an overheat. I'd fire it up cold and watch that setting where you got the 90 from and see where it starts and where it stops in relation to the dash gauge, no telling what parameters the programmer used when writing the code... Just a thought...
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