The Folly of the Temperature Gauge - Jaguar Forums - Jaguar Enthusiasts Forum


XK8 / XKR ( X100 ) 1996 - 2006

The Folly of the Temperature Gauge

Reply
 
 
 
Thread Tools Search this Thread
  #1  
Old 10-29-2011, 09:12 PM
OregonJag's Avatar
Senior Member
Thread Starter
 
Join Date: Jun 2009
Location: Lake Oswego, OR
Posts: 346
Thanked 76 Times in 52 Posts
Lightbulb The Folly of the Temperature Gauge

It's simply a philosophical issue I suppose. The engineers programming these things believe, or are told to believe, that someone who spends 100k on a car does not want to be bothered with gauges that don't look perfectly normal all the time. When the red blinky light comes on or it doesn't go any more they'll call a tow truck and send it to the place they bought it from because it is under warranty and not their problem.

Fast forward to the post warranty years and those of us that bought something we could work on and keep running ourselves for the low low price of 10% of sticker. Given the information and the eye candy formerly known as engine gauges, we will be needing something more for diagnostics, or in my case, normal everyday running. After all, these are spectacularly great cars that with some good ol' TLC will go the distance.

To wit: the Engine Temperature or Coolant Gauge.
It climbs normally up to the 50% mark where it resides steadfastly through a seemingly spectacular range of temperature. Then it continues on apparently into the red zone. I should say that I have no data to support the trend line above the 50% mark save for my own memory in the heat of the moment.

Attached are some pics of my '97 XK8 engine temperature gauge with my ScanGaugeII along side. I also included a little chart that shows the "flat line" in the middle of the range. Some would say I have some maintenance to do on my cooling system and I agree. Just gettin' 'round to that.

One last thing, as a Control Systems Engineer, programming a gauge to do this is very easy when it's built like any late model car. This is no different than what we can do on any industrial man-machine interface.

..and now for more wine...
Attached Thumbnails
The Folly of the Temperature Gauge-94deg.jpg   The Folly of the Temperature Gauge-118deg.jpg   The Folly of the Temperature Gauge-154deg.jpg   The Folly of the Temperature Gauge-181deg.jpg   The Folly of the Temperature Gauge-188deg.jpg  

The Folly of the Temperature Gauge-200deg.jpg   The Folly of the Temperature Gauge-211deg.jpg   The Folly of the Temperature Gauge-220deg.jpg   The Folly of the Temperature Gauge-datachartplot.jpg  
Reply With Quote
The Following 12 Users Say Thank You to OregonJag For This Useful Post:
bazjag (03-15-2015), beg3yrs (10-31-2011), eieio (06-13-2013), forneycl (08-27-2014), JagYi (10-30-2011), jaidank (10-20-2015), johnd8008 (09-13-2013), JSA (06-02-2014), Orthodixie (05-06-2017), Spurlee (10-30-2011), Stamford (11-27-2011), thommo (01-16-2012)
  #2  
Old 10-29-2011, 09:24 PM
Skid Mark's Avatar
Veteran Member
 
Join Date: May 2010
Location: Mid Atlantis
Posts: 1,024
Thanked 27 Times in 26 Posts
Default

Please explain how the chart works.
Reply With Quote
  #3  
Old 10-29-2011, 09:52 PM
The Coupe's Avatar
Veteran Member
 
Join Date: Aug 2011
Location: South Carolina
Posts: 1,293
Thanked 344 Times in 221 Posts
Default

We're waiting for WhiteXKR (The JagWrangler) to invent the workaround for this ridiculous temperature display (I won't call it a gauge).

You ARE working on that for us, right Jagwrangler? I'll be your first customer.
Reply With Quote
  #4  
Old 10-29-2011, 10:11 PM
Senior Member
 
Join Date: Sep 2010
Location: st. john's
Posts: 122
Thanks: 0
Thanked 13 Times in 11 Posts
Default

Nice to see a plot of actual and what the guage is saying
Great work with that plot
Wow it sure says 50 percent for a wide temp swing
Which I was suspecting
It is a very nice analog looking guage but it is just that
Eye candy and does not tell you much but now at least with the chart when it climbs to 60 percent the coolant temp has gone up !!!!!
If there is a work around that would be great
But I guess an aftermarket one may be possible which I was asking about in a previous post

Hats off again for the graph

Howard
Reply With Quote
  #5  
Old 10-29-2011, 10:30 PM
OregonJag's Avatar
Senior Member
Thread Starter
 
Join Date: Jun 2009
Location: Lake Oswego, OR
Posts: 346
Thanked 76 Times in 52 Posts
Default

Skid-
The graph shows on the horizontal axis the gauge swing from 0% to 50% to 100 %.
The Vertical axis shows the temperature readings from my scan gauge that is plugged into the OBD-2 port.
The pictures is where the data table on the chart comes from through 220 degrees F. Above 220 degrees is from my memory.

The scan gauge reads what the computer (ECM) sees from the engine temperature sensor.
The reading on the gauge is the PROGRAMMED output on the ECM channel the gauge is wired to.

Coupe-
The way to properly fix this is to change the programming. Any of the aftermarket ECM re-programmers could do it if it was worth their time ($).

Mike
Reply With Quote
The Following User Says Thank You to OregonJag For This Useful Post:
Skid Mark (10-30-2011)
  #6  
Old 10-29-2011, 10:55 PM
The Coupe's Avatar
Veteran Member
 
Join Date: Aug 2011
Location: South Carolina
Posts: 1,293
Thanked 344 Times in 221 Posts
Default

I wonder if the gauge could be reconfigured somehow and paired with a bluetooth receiver to read the coolant temp from a bluetooth sender connected to the.OBDII port.

After all, my Droid can do this with the Torque app, and we could bypass that ridiculous ECM temp programming altogether.

Last edited by The Coupe; 10-29-2011 at 11:02 PM.
Reply With Quote
  #7  
Old 10-30-2011, 12:47 AM
plums's Avatar
Veteran Member
 
Join Date: Feb 2011
Location: on-the-edge
Posts: 9,731
Thanked 2,085 Times in 1,566 Posts
Default

Or just buy a aftermarket gauge.

The way the gauge behaves is worse than an idiot light. At least with an idiot light there is no mistaking there is something wrong.

The whole time it is creeping up from 180F to 220F, time that the driver could have used to decide to pull over, it is lying.
Reply With Quote
  #8  
Old 10-30-2011, 07:38 AM
WhiteXKR's Avatar
Veteran Member
 
Join Date: Apr 2010
Location: Arlington VA USA
Posts: 7,348
Thanked 2,602 Times in 1,954 Posts
Default

Quote:
Originally Posted by OregonJag View Post
Skid-

The scan gauge reads what the computer (ECM) sees from the engine temperature sensor.
The reading on the gauge is the PROGRAMMED output on the ECM channel the gauge is wired to.

Coupe-
The way to properly fix this is to change the programming. Any of the aftermarket ECM re-programmers could do it if it was worth their time ($).

Mike
Quote:
Originally Posted by The Coupe View Post
I wonder if the gauge could be reconfigured somehow and paired with a bluetooth receiver to read the coolant temp from a bluetooth sender connected to the.OBDII port.

After all, my Droid can do this with the Torque app, and we could bypass that ridiculous ECM temp programming altogether.
Quote:
Originally Posted by The Coupe View Post
We're waiting for WhiteXKR (The JagWrangler) to invent the workaround for this ridiculous temperature display (I won't call it a gauge).

You ARE working on that for us, right Jagwrangler? I'll be your first customer.
First off thank you OregonJag for drawing a clearer picture of the behavior of the coolant gauge.

From the architecture of the system, my expectation is that the ECM is always putting out the correct temperature over the internal network in the vehicle. It is the computer in the main gauge cluster that 'filters' that data and then drives the stepper motor type gauge. I would be surprised if many 'tuners' had the tools to reprogram the instrment cluster computer.

In my view, the easiest way to make a correct reading gauge (and easy is a relative term) is to disconnect the gauge from the speedometer cluster and monitor the analog temperature from the temp. sensor with a small microprocessor and have this small microprocessor drive the gauge stepper motor directly.

I currently have quite a backlog of products I am developing, but I think there is enough interest in this, so I am going to add it to the list. It is going to be a while though
Reply With Quote
The Following 2 Users Say Thank You to WhiteXKR For This Useful Post:
Bob OB (09-12-2013), XK8Troll (01-06-2012)
  #9  
Old 10-30-2011, 08:01 AM
The Coupe's Avatar
Veteran Member
 
Join Date: Aug 2011
Location: South Carolina
Posts: 1,293
Thanked 344 Times in 221 Posts
Default

Quote:
Originally Posted by WhiteXKR View Post
I currently have quite a backlog of products I am developing, but I think there is enough interest in this, so I am going to add it to the list. It is going to be a while though

If enough of us pester you about it, perhaps you could move this particular product towards the top of your list. After all, great as your other products are, this one can help save fellow enthusiasts from inadvertently cooking their aluminum engines. That's important stuff! A rare opportunity to combine profit with a public service.
Reply With Quote
  #10  
Old 10-30-2011, 08:07 AM
WhiteXKR's Avatar
Veteran Member
 
Join Date: Apr 2010
Location: Arlington VA USA
Posts: 7,348
Thanked 2,602 Times in 1,954 Posts
Default

Quote:
Originally Posted by The Coupe View Post
If enough of us pester you about it, perhaps you could move this particular product towards the top of your list. After all, great as your other products are, this one can help save fellow enthusiasts from inadvertently cooking their aluminum engines. That's important stuff! A rare opportunity to combine profit with a public service.
Public opinion will win here...I'm listening
Reply With Quote
  #11  
Old 10-30-2011, 08:17 AM
The Coupe's Avatar
Veteran Member
 
Join Date: Aug 2011
Location: South Carolina
Posts: 1,293
Thanked 344 Times in 221 Posts
Default

Quote:
Originally Posted by WhiteXKR View Post
Public opinion will win here...I'm listening
OK everyone, you heard the man.

Those of you who would like WhiteXKR to develop a product that turns your current temp gauge into something USEFUL, post up your interest here!

I'll go first...please do it!
Reply With Quote
The Following User Says Thank You to The Coupe For This Useful Post:
Bob OB (09-12-2013)
  #12  
Old 10-30-2011, 09:14 AM
avt007's Avatar
Veteran Member
 
Join Date: Sep 2010
Location: Langley BC
Posts: 2,205
Thanked 519 Times in 404 Posts
Default

Don't feel bad, BMW does exactly the same thing. My 330 trip computer could be made to read the real temp digitally, while the analog indicator gave you the "feel good" reading.

As an Aircraft Maintenance Engineer, specializing in electronics and instrumentation, this is unforgiveable.

Not as bad as some Fords I've had, where the oil pressure indicator is really an idiot light, showing pressure or no pressure.

Last edited by avt007; 10-30-2011 at 09:16 AM.
Reply With Quote
  #13  
Old 10-30-2011, 09:37 AM
Mikey's Avatar
 
Join Date: Oct 2009
Location: Perth Ontario Canada
Posts: 10,842
Thanked 2,129 Times in 1,751 Posts
Default

Those of us that participate on these enthusiast boards are the true 'geek' owners that represent maybe .1% of the total. Almost all temp gauges on cars operate exactly as described by Oregon to suit the 99.9% that don't know, understand or care what the indication means. If you think of why many cars have idiot lights instead of gauges, if I was an OEM I'd do the same thing.

There was a post not long ago from an owner that drove his car with the gauge pegged until the engine seized. The original engine on my vintage Corvette went bye-bye because the owner at the time thought the oil pressure gauge was an oil quantity gauge and he had enough to get him another few hundred miles or so.
Reply With Quote
  #14  
Old 10-30-2011, 09:43 AM
Veteran Member
 
Join Date: Mar 2008
Location: Pacific Northwest USA
Posts: 16,507
Thanked 4,855 Times in 3,751 Posts
Default

Quote:
Originally Posted by avt007 View Post
Don't feel bad, BMW does exactly the same thing. My 330 trip computer could be made to read the real temp digitally, while the analog indicator gave you the "feel good" reading.

As an Aircraft Maintenance Engineer, specializing in electronics and instrumentation, this is unforgiveable.

Not as bad as some Fords I've had, where the oil pressure indicator is really an idiot light, showing pressure or no pressure.


Jaguar starting going to the "idiot gauges" in the mid-90s. My '95, for instance, has idiot gauges for both coolant temp and oil pressure. And, yes, many other car builders have done the same.

I was a bit disturbed by this at first but eventually shrugged it off. The oiling and cooling systems, on the old X300s at least, are virtually dead reliable...so I became a member of the placated "if it still runs everything must be OK" masses :-)

I find it amusing that Jaguar left the voltmeter as an actual functioning instrument, given that we're not entrusted with the truth on the other two :-)

Cheers
DD
Reply With Quote
  #15  
Old 10-30-2011, 09:49 AM
Skid Mark's Avatar
Veteran Member
 
Join Date: May 2010
Location: Mid Atlantis
Posts: 1,024
Thanked 27 Times in 26 Posts
Default

Quote:
Originally Posted by The Coupe View Post
OK everyone, you heard the man.

Those of you who would like WhiteXKR to develop a product that turns your current temp gauge into something USEFUL, post up your interest here!

I'll go first...please do it!
Agreed, sign me up for the first harness after Coupe!
Reply With Quote
  #16  
Old 10-30-2011, 09:52 AM
Skid Mark's Avatar
Veteran Member
 
Join Date: May 2010
Location: Mid Atlantis
Posts: 1,024
Thanked 27 Times in 26 Posts
Default

Quote:
Originally Posted by OregonJag View Post
Skid-
The graph shows on the horizontal axis the gauge swing from 0% to 50% to 100 %.
The Vertical axis shows the temperature readings from my scan gauge that is plugged into the OBD-2 port.
The pictures is where the data table on the chart comes from through 220 degrees F. Above 220 degrees is from my memory....
Thanks, got it now!
Reply With Quote
  #17  
Old 10-30-2011, 10:31 AM
Gus's Avatar
Gus Gus is offline
Veteran Member
 
Join Date: Jul 2008
Location: Berlin Md.
Posts: 10,669
Thanked 1,796 Times in 1,456 Posts
Default

I do agree that the gauges (oil pressure and temperature) in this car are nothing but placebos. I hope you can find a fix.
Reply With Quote
  #18  
Old 10-30-2011, 02:47 PM
Felipe Pr's Avatar
Senior Member
 
Join Date: Apr 2011
Location: PUERTO RICO
Posts: 320
Thanked 24 Times in 20 Posts
Default

Ditto.
Reply With Quote
  #19  
Old 10-30-2011, 04:04 PM
Gus's Avatar
Gus Gus is offline
Veteran Member
 
Join Date: Jul 2008
Location: Berlin Md.
Posts: 10,669
Thanked 1,796 Times in 1,456 Posts
Default

Is the ScanGaugeII (SG-II) fully compatible with your car? It seems that the Ultra Gauge (UG) has a compatibility issue with the XK8/R that they do not wish to address; however, the UG works great in my S-Type so it was not a total loss. I would like to know more about your SG-II and any issues you have with it. Also your temp chart was it a download from the SG-II or did you create it?
Reply With Quote
  #20  
Old 10-30-2011, 04:40 PM
Member
 
Join Date: Sep 2010
Location: S.F. bayarea
Posts: 95
Thanks: 0
Thanked 5 Times in 5 Posts
Default

Do the measurements shown by the graph mean that the normal operating temperature range is from 181 to 230 degrees F ?

Also for over temp or low oil pressure, will the ECM prevent the driver from damaging the engine?
Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
X350 Radiator Fan Extended Operation Seth XJ XJ6 / XJ8 / XJR ( X350 & X358 ) 3 11-01-2015 12:17 PM
What is normal and what is a concern workworkwork XJS ( X27 ) 46 10-23-2015 10:26 AM
XJR overheating & coolant loss vwbusbits XJ XJ8 / XJR ( X308 ) 15 10-13-2015 03:43 AM
2001 X-Type 3.0 P1638 3lvis X-Type ( X400 ) 1 10-01-2015 01:56 PM


Tags
app, bad, bmw, gage, gauge, ii, jaguar, obd, oil, port, temp, temperature, torque, ultragauge, xjr, xk8


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Advertising
Featured Sponsors
Vendor Directory

All times are GMT -5. The time now is 12:34 AM.


JAGUAR and its logo are the registered trademarks of Jaguar Cars Limited. Jaguar Cars Limited is not affiliated with JaguarForums.com.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: