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need temp sender location for 98 4.0

rockwerks

rockwerks

NAXJA Forum User
Location
Chito Beach Resort, WA
swapping into a 95 a 98 motor and cant find the temp sender local, used to be back of the head at teh firewall, where the heck is it now?
 
MAP said:
It's right at the front near the thermostat housing.
Click to expand...

that is the sender for the electric fan not the gauges, they are different creatures, unless I need to buy a new one for a 98 that combines both?
 
On 97+ XJs at least, the engine computer uses that same sensor to control the gauge, and to let the computer know the temperature of the coolant/engine so that it knows to activate the fan and change fuel mixture etc...
I found this out a couple years ago.. The gauge would show cold yet the XJ had been running a while. This caused the engine to run rich because the computer thought the engine was cold when in reality it was hot.
Cleaning the contacts of the connector and sensor solved the problem.

MAP
 
MAP said:
On 97+ XJs at least, the engine computer uses that same sensor to control the gauge, and to let the computer know the temperature of the coolant/engine so that it knows to activate the fan and change fuel mixture etc...
I found this out a couple years ago.. The gauge would show cold yet the XJ had been running a while. This caused the engine to run rich because the computer thought the engine was cold when in reality it was hot.
Cleaning the contacts of the connector and sensor solved the problem.

MAP
Click to expand...

so I guess I have to add a location for the sending unit for teh gauge.....any ideas/ or splice it in?
 
A few years back, I swapped a 97 4.0 for my 91. I (very carefully) drilled and tapped the head with the 1/8 NPTF threads for the oem sender from the 91 motor, installed, never had a problem.

Question is...I've just acquired another 98 4.0 to put in place of my 93....Is drilling into the head at this location a bad idea? As I said before, I never had a problem when I did it the first time, but this motor is cherry, don't wanna screw it up. There's a flat spot on the later model head where the sender should be...
??
 
anyone? anything at all? I also noticed there is a pipe-thread plug on the drivers side of the block, behind exhaust manifold, I'd say about 2/3 of the way back, roughly in the middle...will that work???

I want to make sure I get an accurate temp reading, since the #6 cylinder runs the hottest, right???
 
If when you remove the pipe thread plug, coolant comes out, it should work. I wouldn't worry too much about whether or not you're reading cylinder number 6. The coolant moves around pretty fast, and the main point of the gauge is to keep track of trends. Any location that reads the coolant temp will do that all right.
 
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