Hello all. I have an xtype I'm fighting with. On long drives the guage will show over heat. Turn off the car and it's instantly cool again and off i go. Then red light a few minutes later. Maybe. Lol

I hooked a obd2 computer up to it and graphed the coolant temp. It stays between 172 and 176 despite what the guage shows.

So I'm guessing my.guage is busted or whatever drives it. Thing is... Am I actually overheating?

I changed the water pump and thermostat before I tried data stream with the bosch scanner I have


Thanks all!

 

I just had the same thing and it was the temperature sender on the coolant manifold; it's a quick fix.
If that doesn't sort it then you may have a coolant leak somewhere; are you losing any coolant?

 

No lost coolant. Isn't making oil either. . Where is this sensor? I'll get one but I can't find a manual on this car.

 

https://www.google.com/search?ie=UTF...SqlYTNMBuN85M:

 

Excellent! The graphic shows two though... Are they both the same sensor? Just two spots? Or is it going to be one of those either here or there depending on nuances of car things

Thanks!

 

One is the fuel sensor the other is coolant sensor.

 

super good!

Any ideas why the OBD2 would be showing a sane temp while the guage shows something rediculously overheated? thats the part that bugs me the most. if there's only one sensor. or does the guage go nuclear if the system thinks there's a problem with the sensor while the odb2 continues to show its output?

I appreciate everyone's help! i'll get the sensor ordered

 

OBD gets the reading from the ECU I believe, the cluster idk. Someone with more knowledge may know that answer. I know I read somewhere over a year ago that the gauge doesn't really reflect a true temperature. It is around half way as long as the monitored (from where idk) is within "normal" operating temperatures. For instance, temp from 170-210° F doesn't move the gauge if you had noticed when it was working. Unlike the old car gauges that fluctuated in real time to temperature changes.

 

CTS testing on a Jaguar =


This page is devoted to testing the CTS (coolant temperature sensor) and the CTS wiring harness on your Jaguar. The CTS, the harness wiring, and the harness connector, are all prone to failure. The CTS pin contacts, and the wiring harness contacts are also prone to failure due to corrosion. Failure of any of these items, will cause a no start, a hard start, or if the engine starts, poor idle, or overfueling, and a possible shut down of the engine shortly thereafter. The usual engine result is it will overfuel, and cause a no start.



Prior to discussing failure of the CTS, or the harness wiring, we need to understand the function of the CTS....



The CTS is an important primary engine sensor, and is typically threaded into a port on the B bank thermostat housing. The CTS "measures" coolant temperature, as a heat resistance value, and transmits that value to the engine ECU, The value is measured in ohms resistance. The mapping table within the ECU interprets the resistance value as engine coolant temperature.



A cold engine requires more fuel. More fuel is required on a cold engine, because the fuel injected into a cold engine does not evaporate completely (engine heat aids fuel evaporation), so additional fuel is added to aid in a cold start. The added fuel is based upon the mapping table of the ECU, which is measuring the resistance value of the CTS, and is adding fuel accordingly.



Aditional fueling is likewise added by the ECU, based upon resistance values of the CTS, to overcome engine friction, which is another factor to consider on a cold engine. The ECU has been mapped accordingly to provide an injector pulse width to provide enriched fueling (on a cold engine) to overcome engine friction, and the reduced atomization of fuel.



As the engine begins to reach warm up temperature, the CTS resistance (ohm) value decreases and the ECU begins to reduces injector pulse width accordingly....adding less fuel. Once the engine is fully warm, there should be no pulse width correction added by the ECU.



NOTE !! Prior to conducting any test shown below, it is recommended you read everything first, and then select the method(s) most suitable. Also, try the "quick test" first, which is detailed further down this page.



The CTS can be tested with an ohm meter. Do not start the engine. Pull the connector from the CTS. Touch one probe of the meter to one pin on the CTS. Touch the other probe of the meter to the other pin.



The resistance values at various engine temperatures shown below should be within 10%.



0 degrees C (32F) 5.9 kohms

10 degrees C (50F) 3.7 kohms

30 degrees C (86F) 1.7 kohms

50 degrees C (122F) 840 ohms

70 degrees C (158F) 435 ohms

90 degrees C (194F) 250 ohms



It is also possible to test the resistance values with the engine warmed, but NOT running. Start and run the engine to full warm up. Turn off the engine, and remove the connector from the CTS. Test as per above.



Testing the CTS on the vehicle requires some method to measure the engine or coolant temperature. An infrared temp gun is useful, aimed at the thermostat housing on the B bank side. See table above for engine temps...cold and hot.



If you don't have an infrared gun, you can remove the CTS and test it in a pan of water. Note...you will loose some coolant when removing the CTS, so something to plug the hole may be advisable. Maybe a rubber plug, fishing cork, or similar.



On the stove, you'll need a cooking thermometer to measure water temps. Pliers to hold the CTS...(an assistant would be helpful) and your meter. Measure the initial temps and values without warming the water. If you want to measure for values at the lower temperatures, add some ice to the water. Begin heating the water, and check as per above.