I've been working on the XJ 12 for the last few weekends with the main aim of getting the engine turning over
It's car No 25 of about 700 produced and has been sitting in a semi stripped state for at least 14 years. Eight of the twelve pugs came out but four snapped off in the head. This area of the head had obviously been exposed to the elements and the plugs have welded themselves to the head. I've been working slowly on these with much googling and assistance from Grant Francis, one has since been extracted. Three to go. Time and penetrant are doing their thing.
I've had the bores filled with ATF/Deisel for a couple of weeks and was getting no where on the crank nut. It's obvious this was going no where without some serious muscle on the fly wheel. Thought, what the heck, try the starter!
The wiring under the bonnet is pretty dodgy so gave it a once over and made sure I had no shorts. Hooked up the battery and ....click. Could hear a couple of relays under the dash pad click in, but nothing on the starter solenoid. Took the cap off the starter relay and manually closed the relay. Big click! Starter solenoid kicked in but no rotation. Tried again and Whoosh! Diesel shot out of plug hole six and made a huge stinky mess. Left it to soak a bit and later tried again manually activating the relay. Turns over nicely now...but, why won't it crank on the key.?
I've got an earth through the gearbox switch, but no 12 volts on the yellow/white from the starter switch. As you can see from the pics, I've stripped the dash down to get a good look at the wiring and uncovered the two relays under the dash pad. Both these click in when i energise the ignition switch. But I can't seem to find where the yellow/white wire goes that's at the start relay. Diagrams show it going direct to the ignition switch, possibly via one connector, but there only seem to be four thick wires at the rear of the ignition switch. I'm wondering if there is another lockout or relay somewhere in the circuit?
Does anyone have any ideas?
I've got a lot of sorting out before I can even attempt to start this but cranking on the key is going to be a good motivator to keep going.
Thanks in advance. Alan


Motor now turning over.



Start relay not energising

 

Hello Alan. Greetings and congrats on your persistence . . . few things more dispiriting than sheared spark plugs . . . or snapped studs . . . or fractured castings . . . or small tools that, having slipped from tired fingers, never reach the ground! But, you are making progress. Well done.

Suggest you clarify correct operation of start circuit at ignition switch. I am unclear at what point relays are clicking in . . . ignition ON, or START . . . which? The switch can fail; perhaps not common, but check. Then trace to start relay coil input. Are there hidden line connectors? Unsure, but if you now have both ends of what needs to be an unbroken lead, unclip relay end and check for continuity. If OK, turn ignition to START. At this point you should see +12V at the unclipped relay end of lead. If NOT OK, go line tracing to find dead connector or broken wire. Repair. Reconnect lead to relay and repeat tests. If relay does not click in, dead relay . . . replace and repeat. Takes longer to write than to do.

Hope this helps Alan. You are tackling an admirable challenge so we wish you continued success. Keep us posted.

Cheers,

Ken

 

Alan,

WELL BLOODY DONE.

Now, who said the V12 is a weak engine????????

Somewhere in the shed are some early wiring diagrams, but I have been called in to work tomorrow, so when I get home, and it drops down a tad from 39c, i will go looking.

In the mean time, IS the neautral start switch passing the earth of that relay?????. Again, no idea on a S1 where it is, but if it dont provide an earth for that relay, that relay no work.

 

Ditto. The starter interrupt is a prime culprit. A safety thing to insure that the engine can opnly be cranked when the transmission is in park or neutral. Done in differing ways. One is a micro switch on the shift tower. Another is a switch on the transmission. Generally, and very much so, BW's have a switch on the transmission. GM's do not, so one is provided on the shift tower.


Check the relay for a black wire on one pin. That should be the ground leg. Jump it to ground. Now, try to crank with the ignition switch. If it does, there is a wire, connector or interrupt switch issue.


And, yes, switches do fail. They are not that robust. And the years take their toll. A heavy key ring exacerbates the wear Odd things happen. Been there, done that. A NOS switch via David Boger fixed a lot of things!!!


Carl.

 

Thanks guys for the encouragement. Need every bit of it with this project.
So, this afternoon I located the loom/plug with the W/Y for the start from the ingnition in the corner behind the firewall. Plug connectors were clean and all the metal pins were greased like it had been done yesterday. Out with the multimeter. Hmmmm....open circuit between the plug and the relay. Traced the wiring back from the relay. This was made much easier by the lack of cotton cover. Loom goes over the back of the brake booster and through the firewall. Stuck my head and torch as close as I could get for a better look in there. Sure enough, my wiring has been nibbled. Reckon I've found the kitchen of the mouse colony that once lived in there. Looks like several of the wires are chewed.
I had checked the earth through the neutral switch. This was giving me a solid earth at the relay, so at least I don't need to go grovelling around the BW box looking for that.


Open circuit



Mouse food



It's in there...


So, it's either pedal box out or loom pulled through for repairs.��
Onwards

 

Just got home, so much for 5 hours fill in.

Breakfast looks like the issue, but I will go looking for those drawings in the morning.

 

Great. WY, a mouse's delightful desert. Wonder which colors became the entre and sides????


Carl

 

This afternoon I had a look to see what was the best way to get to the damaged loom
With a few plugs pulled and some loom clips, vent pipes etc removed I was able to pull it back into the engine bay for a better look.


This bit looks good 😊



Breakfast, lunch and dinner


There were five wires nicely chewed but only the start relay wire was chewed right through. Did these mice know something about Lucas electrics?😳? Certainly one way of ensuring your cosy new home stays where you left it.
Also accounts for the seemingly never ending shredded "newspaper" stuffed in here.
Out with the soldering iron now......then its back onto those broken plugs.
Anyone know how to get a broken Ezyout out of a broken plug? ☹️

 

Hey Alan . . . this thread and your persistence in tracking into the most hidden and thus, mouse friendly, recesses . . . has brought you to the predicted cause . . . and solution.

I and many others will continue to follow your great work.
Best wishes mate,

Ken

 

Durn good. Finding the fault is the toughest part. The fix much easier, at times !!!


Busted EZY outs???? Decades ago, I vowed to never, ever resort to the use of them.
Contrary to my philosophical views on ever and never...


They are very hard, thusly brittle. Bust and a no drill available to most will touch them. Heat to anneal? In situ, not possible.


I have a vague recollection of a special process to 'atomize' them. Details not recalled. But, again, the in situ issue.


So, that leaves me with only a limited suggestion. If the break is in the threaded and fluted part, a tool might be devised to insert there and allow a wrench (spanner) to turn it and back it out....


Tons of luck needed....


Carl

 

Carl . . . your reference to "atomizing" . . . and busted easy-outs, has me a little confused but also brings back memories of the sure fire fix I saw developed in the sixties. But first, Alan . . . have you busted easy-outs now lodged in the seized remains of these spark plugs? If so, I missed that.

In any event, the memory Carl has jogged into my mind flows from the development and medical application of canned pressure-pack freezing coolant. I know this stuff is common now, but it was a novelty then . . . and certainly something I picked up on when I saw it employed.

Trick was in 3 parts - first, drill the busted stud to accommodate the easy-out, but probably not necessary for a bust spark plug . . . secondly, the simultaneous heating of the main body of the part holding the busted stud (in your case, both upper and lower faces around plug hole in removed head), while squirting freeze spray at the busted, seized remnant of plug . . . and thirdly, biting the easy-our into the broken part to unlock it from its grip. Same process was applied to freeing up a broken easy-out . . . heat the body; freeze the stub of easy-out; wiggle to unlock.

It was Carl's use of the term "atomize" that recalled this process and, Alan, I hope it helps. I recall it became an often used remedy for really stubborn (or broken) exhaust flange studs . . . far smarter than snapping off a corner of those cast flanges.

Best wishes,

Ken

 

That sounds like a logical approach. Heat the outter to expand it. Cool the inner to shrink it. Hold loosened enough to extract.


But, I just had to explore "atomization". Well, a bit of an overstatement. I did a quick "Google" and found Electrarc.com. Sales point. And a description of processes. One is MDM, Metal Disintegration Machine. A spark erosion process. Exactly for these issues.


Another is EDM. More complex.


My general word search also brought up classic machine shop techniques on this stuff.


Carl

 

Got the wiring soldered up, re taped and tucked back in



Soldered and re insulated



Re taped and tucked in

Now turning over on the key 👍🏻
Did a few other checks while I was at it. All four electric windows go up and down and the dash lights and wipers work.
Lucas electrics gets a lot of bad press, but from my experience it's quite often the years of use and abuse (as is the case here) that is the real reason for dramas.
Now....onto those broken plugs!

As an apprentice on the mines they used to have a disintegration type machine for the unavoidable instances where the apprentice in his haste snaps off a drill or tap. I'll just have a look around the shed to see if I've got one....nope.
When all else fails, improvise. I've got a couple of ideas

Local chemist has freeze spray for removing skin tags etc. it may be more effective at pure cooling than the can of the "freeze your nuts off" from Repco that I've already tried.
Tomorrow's another day 😁

 

Great progress Alan . . . and a very neat fix that, as bonus, fixed a few other hiccups also. Well done, that man! Keep us posted.

Cheers,

Ken

 

Agree. Found fixed. As to electrics.


A new thread on the stuck spark put and busted "Ezy out" seems a good idea.


Good luck on that endeavor....


Carl

 

New thread on busted plugs + busted ezyout will be posted.
I still have three stuck plugs but at this stage have managed to drill out the broken ezyout.
More on this in the new thread.
It's my wife's 50th birthday this weekend so might curtail shed tinkering somewhat.
I'm thinking she might like a new set of ezyouts, some tungsten burrs or perhaps a new socket set?😂

 

I am sure she will LUV those items, and they should see her through until the next big event, DIVORCE.

Maaaate, take her to Las Vegas, we are about to do trip #13, happy wife, HAPPIER husband.

 

DITTO to the nth power. Whatever she enjoys most. Do it.


Dear departed and I enjoyed 54 great years, and then she passed. My solace is that we made the most of them. Do it.....


Carl