On a 2000 XKR- if the car were to overheat would there be any warning (other than the gauge)? Would the car go into limp mode or RP if it went over a certain temperature and throw a code that would stay for the next start. In trying to figure a failure analysis, it is hard for me to think the car would overheat enough to cause problems with the head gasket and would not give some indication.

Thoughts or knowledge.

Thanks

Tom in Dallas

 

My 2004 XKR was notifying me via the message board that I had low collant for an entire day. I was constantly monitoring the temperature. I left my house and went about a 1/4 mile when I noticed that the temperature had sky rocketed into the red zone so I turned around and limped back home immediatly. Turns out I had blown (2) hoses under the supercharger. Never once did it notify me that the temperature had gone into the danger zone. No codes either. Kinda scary, luckily I was close to home.

 

The temperature gauge is 'non-linear' which means that it will read in the dead center of the gauge over a broad range of temperatures. Exceed the upper threshold and it will instantly go to the top and light the 'replace the engine' light.

I ride a Honda Goldwing that had a problem when first introduced in that when riding slowly, as in parades, the temp gauge would creep up to the 'hot' level. There was a recall that installed a resistor to keep the gauge in the middle until it reached an unacceptable level. Boy, that solved the problem.

 

My Harley's temperature sensing setup is more primitive. If you have a 1st degree burn on your leg, the bike is getting too hot.

 

. . . and then there is the ambient temperature gauge on the Harley that always reports 95 degrees plus/minus 20 degrees whatever the local temperature might be.

 

I've got a ScanGauge on my 97 that shows me what the ECM is seeing before it sends the signal to the temperature gauge. At 179 degrees F the needle on the gauge hits the halfway or 50% mark. On a hot August afternoon with the AC on running through eastern Washington I saw 230 on the ScanGauge and the needle is still parked at 50%.

 

OJag,

Does your ScanGauge monitor transmission fluid temp?

 

sigh ... so the temperature gauge is basically useless.

 

Do any of you EE's have a practical fix for the stock gauge to make it more linear? I suppose it's always an option to add a gauge with its own sender, but it would be nice to have the one that's there work like it should.

 

That would be a great "enhancement".

 

Unfortunately that would require some hacking. It appears that the temperature comes digitally from the ECM over the CAN bus to the speedo cluster, which uses a stepper motor drive for the gauge. Since that data is used elsewhere, it is likely 'smoothed' by the computer in the speedo cluster itself.

You would have to disconnect the computer drive from the coolant stepper motor gauge in the speedo cluster, then add a small processor to read the temperature data direcly from the sensor and drive the stepper on its own. Possible...yes. Trivial...no.

Or else try to hack into the software directly in the speedo cluster, which probably would be even more difficult.

I am not seeing an easy plug and play scenario.

 

BTW, my HKS CAMP 2 system (see the link in my sig.) has a coolant meter which read the temperature over OBDII and presents it on the navigation screen. It has an alarm feature, which is user settable to sound an audible alarm when a guage goes out of the normal range. It works even if the video is switched to navigation.

It is a great system, but was expensive.

 

If the 97 has that available in the ECM and we could determine the address and scale then yes it could. I haven't found the time to research it and it is not one of the standard OBD-II data points that are pre-programmed in the ScanGauge.