So I got some more results yesterday. I had to put the car into ETM before each startup so that I could watch the various registers.

This forces a reset of the meters before you begin and that eventually exacerbated a problem with the speedo.

The first few times I did the meter reset over the last few days it would go through the sweeping motion and re-calibrate nicely. I have been having problems with both the tach and the speedo. Yesterday it was the speedo's turn. The tach never malfunctioned. You could hear the speedo grinding a bit during the re-calibration cycle but it has now stopped resetting properly. It now seems permanently broken. The digital register seems accurate though it took me a while to realize that it reads out in 10ths with no decimal point so 600 is just 60 mph.

Seems like I need a new gauge cluster?

 

Oh
Maybe someone (bbm-reman?) fixes them?

Leaves the car off road for a while, though

 

Drove the car for 160 miles and 4 hours again yesterday.

The gauges started out perfectly. I did not attempt an entry into ETM so they did not get "reset" after finishing up a total mess yesterday. They ran perfectly for at least an hour and then at some point the speedo went nuts again followed a while later by the tach.

Lucas, the prince of darkness lives yet ...

Frankly, after the previous day's behavior I would have thought they were toast. So it sounds like after a while some circuit starts going nuts.

 

Could easily be a loose cable or a dry joint (that means solder that's either always been inadequately done or in colloquial speak has now degenerated for any reason, perhaps mechanical stress). Any electronics tech might fix the solder kind if it's that but a reman firm would probably be a safer bet.

Doesn't seem common, which probably isn't any consolation sorry!

 

So I haven't given this any attention as I'm busy with other things and paying that much for the repair at a dealer isn't exactly tempting.

I drove about 600 miles round trip this last weekend and the car worked fine. The speedo & tach never missed a beat. Monday morning driving in local traffic it immediately went nuts again after only a few minutes.

I'm really surprised that the entire weekend's trip was flawless. We encountered some bumpy roads in Baltimore too.

I guess Lucas The Prince of Darkness stayed home ...

 

This got resolved. details here:

https://www.jaguarforums.com/forum/s...ies-usa-74438/