81 XJ6 Odd Electrical Issue
 

Ok, I am pretty stumped on this problem.
So the car starts and runs pretty good at idle, but when starting from cold in the morning if I gave if full throttle it would get to about 2000 RPM and then start to sputter and the RPMs wouldn't get any higher until I let go of the gas. After warming up everything seemed fine and I assumed it had something to do with the cold start circuit and hadn't fixed it yet.
Fast forward a few days and a new symptom appears, after a cold start I get interference on the radio that perfectly follows engine RPM and it doesn't idle well, some times at idle the engine stumbles a little and my blowers slow down substantially at the same time.
Shortly after at a stop light while looking for a place to park it and investigate it died completely. All electrical power was cut, like the battery was disconnected, but when I measured the battery voltage it was at nearly 13 volts and seemed totally ok.
It remained completely dead with no electrical power for a few minutes, and just when a friend arrived to help push me out of the street, I turned the key and everything came up. It fired right up, the interference on the radio was gone and it drove home with no issues at all.
So today I disconnected the thermotime switch thinking maybe there was a short circuit in the cold start circuit somewhere, but it didn't seem to make any difference.
Anybody had a similar experience? What could cause the power to cut out completely and then come back? Like some sort of thermal cut out for the whole car?
Very confused by this one. Hopefully somebody has an idea!

Loose or dirty ground connections, maybe worth while checking before you get told it will be expensive.

My guess would be the 35 year old ignition switch, but its just that, a guess!

They are getting old and worn out! Carl will likely know more about the ignition switch issues as he went round for round with his issue. He will chime in shortly im sure.

Agree, Oh did I go around the ring on that one.


Clue one. So much is routed through the ignition switch. Including the brake lights.


Radio. Weak signal or losss thereof and static.


Crank/no crank on a whim.


Static in time with RPM denotes an ignition issue. Low volts from a sloppy switch very possible.


Diagnosis:


1. If the key first loosely and the tumbles is loose, it can mean the inside contacts are also flakey. Mine was much sloppier than the David Boger sourced NOS unit.


2. Drop the driver side scuttle and you will see a connector. Brown in's are unfused battery direct. Check for volts. Whites are switched
power out. Check for volts in start and run. Weak or none, you have it.


3. When the car has a hissy, jump 12 to the coil and with the car in Park, jump 12v to the starter solenoid. You've bypassed the switch. If it cranks and runs, you have it via a different diagnostic path.


It is fiddly to remove, but doable. Some say it can be serviced
in situ. Better men than I Gungha Dins !! If you want to try,
do it in a plastic bag per Grant's advice. I did it before reading that.
Lost teeny pieces.


I strongly suspect you will be doing a switch replace.


Carl

el ignition switcharoo.

Is it "el" or "la" Seems more like the latter....


Carl

in Spanish Switch is masculine, so it is "El Switch".

example: if you want to say "that's a switch" in spanish, you say "Eso es un switch".

Un is masculine, Una is feminine. Eso is masculine, Esa is feminine, so in the spanish translation you have two masculines, Eso and Un.

The word for Switch is spanish is: "interruptor" or "interrupt". But the word Switch has become Spanglish around the world.

OMG..... now i have to worry about the sex of my switches??? What is the world coming to?? Lmao

Oh never mind i see all switches are masculine. Lol

Not only sex ....but Nationality Too!

Jose:


I am aware of gender in Spanish. I grew up in El Paso, Texas. I survived
high school and college Spanish. In high school, Graciela Gonzales. More than cool and not much older than us. Woweee!!!


In college, John Sharp, a Chicagoan. Not his primary language, but a serious student of his craft. Included the curse words. Again, not yet completed his doctorate, so was not that much older than us.


Both very effective teachers, each in their own way...


I was mostly joking, females being known to be more erratic than we males, according to us...


And la switcheroo probably doesn't exist in Castillian, Spanglish or even Jalle!!!


I delight in words.


Carl

Carl, funny you mention the Mexican girl.

Mexicans speak a very old Spanish, Castillian from Aragón to be exact, because the conquistadores who arrived in Mexico were from Castille and that's the Spanish they brought with them. It is a very refined Spanish, the equivalent in pronunciation to British English as compared to American English.

But the conquistadores who arrived at the first discoveries of the "new" world, being the Caribbean islands of Hispaniola (Dominican Republic today), and then Puerto Rico in 1492, were mostly from the Canary Islands, (yes, islanders too). And they spoke a very slanged if not vulgarized Spanish.

A world of difference in the Mexican and Caribbean islands' Spanish in the sense of pronunciation. It amazes me that Mexicans, even the most uneducated peasant from the countryside, speaks a very refined and correct Spanish.

Jose:


Extremely interesting, without question. Professor Sharp usually
spoke sans the "rolled s's", but on occasion would illustrate them in what seemed to be a bit exaggerated. License, I suppose.


But, if electrics have a gender, it's gotta be feminine!


In the PM's I like to watch about three TV Judge shows. My interest in law survives retirement. One of them is Judge Marilyn Miliani. Miami resident and Cuban in ethnicity. Great looks and extremely smart. Fluent in Spanish and English. On occasion refers to Spanish idioms.


Quien es mas macho? Que cueasta mas es mas barrato.


I understand smatterings in Spanish and German. Perhaps smatterings in English as well.


But. I get it. Spanish in the interior of countries is likely to be "purer".
Corrupted on the border.


Camion vs "trocka", etc.


Electric switches must be feminine if gender is involved...


Boats or ships in English get a female reference. Can't come up with La "boque". Wrong, pretty sure of that. Oh, "barco"??? Male??


Love word play....


Carl
"boque"

I am pretty sure my ignition switch is female, it just has that vibe. I actually did have a little trouble with it, awhile back. I have a zip tie around it that seems to keep it working good but it should probably be replaced. It had some kind of plastic retainer that broke and without it I don't think it was getting a good ground, the zip tie holds it more firmly then the retainer ever did and I thought it would probably be fine. When the car cut out I didn't get hazards either, surely they'll run without the ignition switch?


In any case, that switch is on the top of my list of suspects. I need to dig into it deeper but haven't had the chance yet, I should finally get time to troubleshoot this weekend, I'll let you all know what I find.

Did this ever get sorted?

I've been driving it, the symptoms went away for now. I need to dig into it but life got in the way. A building fell on my wife's car in a storm and then my septic system failed catastrophically, I'm changing jobs, and I just had my third son. When life gets in the way around here, it really gets in the way.

I named this one Morris Gene. I'm an MG guy, Jaguars are new for me.

That is a serious case of life.

Good Luck!

I too am an MG Guy...Have had my '67BGT since 87 and we've been through EVERYTHING together, and this is my second Jag...The B was much more reliable than the XJS (so bad I gave it away), but the 87 VDP (which has been in my family since '88) is a thing of absolute beauty and joy. The technical skills from my MG experience help slightly, if only to give me a ton more patience than I would have had otherwise.

I have a 72 MG Midget which I want to restore. I bought a 77 MGB to replace it as my daily driver so that I could dig into the Midget in earnest. Both are in OK drivers condition, but I'm fond of them. Then I started a job that was a 30 minute commute from my house instead of 2 minutes. I kept driving the B for the first year, and then bought the XJ6, the air conditioning and silence is wonderful on a morning commute.

I put 20,000 miles on the Midget in the first couple of years before I got the B. Though the maintenance schedule was rigorous to say the least, it never failed me once until the brakes went out suddenly on my way home. Someday it will be perfect, in the meantime it slumbers in the back of the garage.

https://cimg4.ibsrv.net/gimg/www.jag...e568971070.jpg

a toy i sold, you can still see the jag in the background!!


https://cimg5.ibsrv.net/gimg/www.jag...fb1fb33d11.jpg

mg 003


Ahhh the good old days, i miss my mg! Cant access the pic from my phone for some.reason but its in my photo album.if you guys wanna check it out it was a total ground up restoration with mods! :)
logged on from computer and figured it out! it was a 75 rubber bumper, had to get rid of the bumpers they were enormous, even in jag speak! lol

K and Darren;


In Germany in 1953, I bought the first and only brand new car in my life. A 53 TD. Many adventures there with it. but, then that life thing.
A wife and child. Bye bye, MG, hello staid 50 Chevrolet four door!!! I brought the Chev home. Odd as I am/was a Ford guy.


In a small German town a guy asked if it was a Moto Guzzi???


Morris, why not, a guy can live with that. Same with Gene. If he decides to be "different, he could become M. Gene Alexander??
Could've been Morris Garage Alexander, huh????


That is one slick MG.,


From time to time when out and about exchange greetings with a guy in a beautiful black MG Midget.


My Jaguar just might get a bit of MG infusion, light buckets...


Carl

Likely a poor motor ground or battery ground.
If the car still has woven ground cables trash them.