Well, you'll naturally get a higher reading, as you've seen, as the alternator is spinning faster...but I'm not sure that your earlier test was innaccurate.

Unless all the heavy accessories are on you really should see higher voltages at idle, even allowing for the somewhat undersized alternator used by Jaguar.

But, if you're not worried about it, I'm not worried about it :-)






I think that's the root of your problem .You've probably got a dirty/loose connection somewhere...possibly as simply as a corroded fuse.

Is the connector plug for the trip computer in good shape?

You'll have to trace the wiring back a bit and see if anything jumps out at you.

Cheers
DD

 

Just so you guys know im not going crazy...i think my trip-computer is actually possessed the crazy lights is a brand new thing after a normal start but the display is a common occurrence. i may have to send this to the guys a roadbend jaguar ...and pay money oh well

 

Hey, that's pretty cool


I meant to come back to this thread a few days ago but forgotted.

For a different project I was rummaging thru all the Jaguar tech bulletins from the 80s and discovered a couple pertaining to trip computers. Apparently the internal circuits were redesigned a couple times to correct erratic operation. As I recall the bulletins were pre-1985 or so.

Without going back and re-reading the entire thread I can't remember if you've swapped out your t/c or whatever....but I'm now wondering if the t/c itself is simply a dud, perhaps an earlier unit lacking the improved circuits?

Cheers
DD

 

This is the original head unit , i have swapped out the module, i was getting the same error from a spare that was given to me by roadbend motors but no idea what year it came out of, guess i may have to hunt for one online

will an 86/87 unit work in mine ?

 

I'm fairly certain that early/late units are directly interchangeable in either direction. Maybe someone will come along with a 100% positive answer.

If you happen to get one from the 'States, though, it'll be calibrated for "USA Gallons" versus those silly over-sized "Imperial gallons"

Cheers
DD

 

Well i just got it back from Roadbend Jaguar, Turns out there was a faulty Volt Meter, which has been replaced, i can see my charge rates have gone nuts around 13.8, and no dimming of lights on crank, for a moment i thought it was fix but again it rears its ugly head, im gonna go hunting for a new trip computer

 

When I was having electronic gremlins, I made a patch cord to connect my digital meter through the cigar lighter outlet. I was able to read voltage in real time and under differing conditions. I exonerated my suspected alternator and convicted my battery. A new to me Optima yellow top and all was/is well.

So, in your case, it seems that the trip computer is not receiving full and steady volts. Not good. Time to get out the S57 schematic pages and/or visit captainjaguarscathouse for the same schematic. Track down the source for volts to the TC. A corroded connector or fuse clip, a frayed wire?

I've theorized diposing of my TC. it works, sorta. But, not all the way for another reason. I think I know how to provide it's missing fuel use data. But, as all or most of the electrics are doing fine, I am hesitant.

The TC in my Jeep has a lot of data and is fun watching it at times!! Much easier to see, though!!

I've thought of elevating my radio to the spot where the TC is. Much better line of sight and access to the puny buttons! Then, adding instruments. Compass, vacuum guage, and perhaps an induction type ammeter. Aircraft style instruments would be neat.

 

PS my Jeep has those levers for adjusting the sound on it's decent sound system. I've monkeyed with them, only to return all to the mid position. But, my ears have definite issues. My aids help a lot, but no matter what they say, it ain't the same!!

 

Hi Guys,

Just wanted to update this thread cause i hate dead threads....i was playing around the engine bay on Sunday...as you do and i found an old vacuum hose that was plugged that used to head off to that emissions control thing on the exhaust side

the hose was so old...it was causing a vacuum leak i replaced the hose and plugged it and amazingly i now have instant fuel readings from the trip computer

my heater controls have resumed as in i now have heat because the tap now has vacuum

i am starting to think the erratic nonsense coming from the unit may have been due to the vacuum leak

 

Potpouri: My 94 Jeep Grand Cherokee has both equalizer and trip computer. To my ears missing with the little levers does nothing! And, with my hearing aids on, little change if any. yet, I enjoy music. Saturday night's Lawrence Welk show had a stirring rendition of Wabash Canon Ball. Tremendous trumpet work by Dick Cathcart! So, the little levers are now centered an stay there!!

Now, unlike the Jaguar, the Jeep trip computer display is overhead. And the numbers bigger. Much more visible and less distraction to look at and read. It is kinda fun!! It has seera setting o see live data. AV mpg is slick. Ordinarily, I am not that MPG sensitive. But, watching the interaction of throttle and numbers is very educational. Light cruise or coast and the numbers get big. On throttle an the numbers get miniscule. And this with a 4.0 inline six!! Kinda lie a 4.2 Jaguar???? Naah a much simpler architecture. But, as tough as nails. Still lively at well over 200, ooo miles.
I treated it to a wax rich wash and Armorall on it's plastic. It is still very shiny and looks great in its Pewter finnish. Not as outstanding as the Jaguar in it's Grosver Brown, when treated similarly.

if I were to mess with the Jaguar fascia, I'd move the rad in to the space occupied by the trip computer. Then, fill the radio space with a clock, vacuum gage, compass and possibly an ammeter!! Probably not gonna happen though. Just musing .

PS, the Jeep has a compass, Very useful