XJ6 & XJ12 Series I, II & III 1968-1992

V12 starter issues

 
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Old 07-21-2016, 10:51 AM
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Default V12 starter issues

Hi all

So I've never had this issue before, but my starter is now dead, wont swing over at all, I'd just finished working on the alternator, fired her up, saw that all was well in the land and switched off, got ready to go throw some gas in and she was dead... I've checked the connection at the starter relay and I'm getting 12 volts there, tried moving the shifter around etc and still nothing, just a click from the relay.

Any advice on how this thing comes out? Looks like some fun from what I can see.
 
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Old 07-21-2016, 02:09 PM
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Nathan:


Good name, same as one of my many cousins!!! My Mom and Pop's
parents had a lot of kids!!!


1. Whack the starter a time or two and try again.


2. Supply 12v power directly to the solenoid.


I understand not so easy on the V12 cars.


But, each in its own way tells a lot.


Yahoo, my band saw accepted the new blade. Bits to adjust
before making some saw dust.


Daughter on the way brings lunch! Yahoo.


Issue with old phone and DSL vendor resolved.


Other Utility provider paper issues dealt with.


Errands in the Jaguar. Purred.


Liquids for me. St. Pauli Girl craft lager. Kibble for CoCo.


Old Am radio quiet and dark.


A good day!!


Carl
 
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Old 07-21-2016, 09:44 PM
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Originally Posted by NathanDD6 View Post
Hi all

So I've never had this issue before, but my starter is now dead, wont swing over at all, I'd just finished working on the alternator, fired her up, saw that all was well in the land and switched off, got ready to go throw some gas in and she was dead... I've checked the connection at the starter relay and I'm getting 12 volts there, tried moving the shifter around etc and still nothing, just a click from the relay.

Find and remove the white/red wire at the starter relay. Note the original location,

Use a jumper wire to apply 12v directly to this wire. This bypasses the relay and everything upstream. Does the starter operate?

If so, you have an upstream problem: the relay itself, or a circuit problem which we can help you trace.

If not, a downstream problem: the starter itself, or wiring to the starter

Any advice on how this thing comes out? Looks like some fun from what I can see.
Let's cross that bridge if we get to it

It's no pleasure cruise. Doubly so if yours is a RHD model. Sorry.

Cheers
DD
 
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  #4  
Old 07-22-2016, 04:38 AM
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Crumbs... Lemme go check now... Someone tell me it is doable? I don't mind getting my paws grubby (or I would have sold this car ages ago) but are any special tools required?
 
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Old 07-22-2016, 04:57 AM
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Right, after some homework (the only homework I ever enjoyed period) it turns out she won't crank, no action from the starter or starter solenoid at all, but, lots of sparks from the battery terminal when I jumped 12v, looks like a dead short, and I confirmed that too, her starter relay wire is earthed... So, a chafed wire maybe...? Is it possible to at least gain access to the wires on the starter solenoid so I can see whats happened there, maybe just replace the wire...
 
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Old 07-22-2016, 05:13 AM
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Right, even more homework has been done, seeing as it is a new problem, I figured if it was a chafed wire, some simple wriggling of the starter wires would show a break in the earth I have, but the multi-meter didn't agree, I now see the positive post on the firewall is earthed! So one big short I'm guessing... Is this positive post known to give any issues? Or am I looking at everything wrong?
 
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Old 07-22-2016, 07:15 AM
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If that +ve post on the firewall was earthed you would NOT be able to connect the battery without massive sparks, and the car catching fire if you actually succeded in doing so. A short like that will burn the insulation off those battery cables in seconds.

That White/Red wire is direct to the solenoid activation terminal, as Doug has said.

I am unsure on the S3 cars, but on the XJ-S that wire has a joiner, just close to the trans dipstick area, and that joiner has cost many a V12 owner a starter motor. That joiner has a male/female spade connector with a rubber covering, and it is easily seperated by simply removing the trans dipstick. Find it, seperate it, close the female end a tad so the male end is a TIGHT fit.

When you jump that wire you will get sparks, it is operating a fairly gutsy solenoid.

The starter relays are well known to get burnt contacts inside, so simply remove that relay, mark the wires and terminals BEFORE REMOVING ANYTHING, TAKE PICTURES EVEN, your memory is not as good as you think it is. Remove the relay cover, clean the contacts, refit and try.

Those original starters can be a pain, but failure is rare in my experience. That wire and the relay are the 2 most common items I have found.
 
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Old 07-22-2016, 08:45 AM
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I have a mental picture of that starter nestled in V12 powered
RHD car. Crowded doesn't begin to describe it.


But, I think the architecture is similar to that in my two cars.
I've swapped out starters in each. Much better access than in yours.


A healthy cable from the firewall post to a post on the solenoid. An end fried off the one in my Jaguar. I replaced it with a sturdier generic cable.


The solenoid has a strap from the other post to the starter itself.


The R/W wire connects the relay on the firewall to a small post on the solenoid.


In one exercise on my Jaguar, I was able to get a crank by jumping
the R/W at the solenoid to the terminal on it from the firewall post.


And, not so smart, but it worked. Big post to big post across the
solenoid. Starter spun, but did not engage. Wire got hot, quick.


One starter fried. So much load that an effort to crank melted the
lead securing the thimble in battery ground. Weak a;;; side post battery. It's on my bench for a source of 12v to test stuff.


Long ago, I rebuilt my own failed starters. There were many!!!
No more, just swap 'em for a quality rebuild. Or, as of late a new Malaysian built GR unit. So much lighter for my old shoulders to support.


I'm with Francis, check out the wires and relay first before convicting the starter....


Carl
 
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Old 07-22-2016, 02:10 PM
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Relay has been checked, got 12v coming out when I turn the key to the crank position.

The solenoid I'm not sure about, not much sound coming from the solenoid when I jump the wire to the battery, and I'm pretty convinced of a dead short, there's some pretty serious current coming through there...

Like I've said before, her positive terminal has continuity to ground, something isn't happy down there... Is it possible for the solenoid or starter to fail and provide a direct short?

Another one, the positive firewall post, how is it held in? do I have to grip a nut/bolt on the inside or can I just take the nuts off on the engine side?

Many thanks
 
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Old 07-22-2016, 02:12 PM
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The joiner, I can't see one on my car, maybe it was omitted on the Series 3 cars, the wire in question disappears into the loom with the heavy positive, which I assume goes to the starter.
 
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Old 07-23-2016, 05:56 AM
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Originally Posted by NathanDD6 View Post
Relay has been checked, got 12v coming out when I turn the key to the crank position.

The solenoid I'm not sure about, not much sound coming from the solenoid when I jump the wire to the battery, and I'm pretty convinced of a dead short, there's some pretty serious current coming through there...

Like I've said before, her positive terminal has continuity to ground, something isn't happy down there... Is it possible for the solenoid or starter to fail and provide a direct short?

Another one, the positive firewall post, how is it held in? do I have to grip a nut/bolt on the inside or can I just take the nuts off on the engine side?

Many thanks
OK, continuity test needed.

You may need to remove the RH air cleaner assembly, including the backing plate. DO NOT start the engine with this removed.

Reach down to the starter, and unplug that Red/White wire. Now plug a DVM (Digital Volt Meter) set on Ohms into each end of that wire. I reckon you have continuity, which is what you need, indicating that wire is OK.

The fact zip is happening when that wire is fed 12v, is indicating the solenoid is jammed or dead.

Our PreHE did this in the early days, and I always carried a socket and bar so I could reach down the front and rotate the engine the smallest amount, and the starter would "clunk" and drop out of mesh with the flywheel. Worked just fine for months, then oops, here we go again. Eventually it just stopped sticking. Never did find the reason, and the new owner has never had an issue with it.

Removing the starter is a monster task, the steering rack needs removing, the tower is in the way, and the exhaust pipe needs to come out of the manifold. IF that pipe will not come out, then the subframe (cradle to some) needs to be lowered about 6".

That +ve post can be seperated and cleaned. Ensure the battery is disconnected please. Undo the nut, DO NOT DROP THAT NUT, it is special thread. Clean up what is needed and resecure without doing that nut up stupid tight, just nice and firm will do.

Have a look at the engine earth strap/s at the LH engine mount area. They may be in a mess, and a bad earth of the engine to the chassis will stop a heap of stuff working. That starter needs a SERIOUS earth path to work properly. Connect a battery jumper cable from the engine (lifting lug will do) and the NEG of the battery, see if anything changes.
 

Last edited by Grant Francis; 07-23-2016 at 05:58 AM.
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Old 07-23-2016, 06:40 AM
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Aha, so I'm not alone here, I'll go give the engine a trun, got a socket that fits, done it before, the fact that shes drawing serious current is whats got me puzzled, I'll try earthing the engine too.

Thanks a lot for your advice Grant, it's always appreciated.
 
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Old 07-23-2016, 07:34 AM
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Tried turning the engine, no luck, managed to turn it, but no "clunk".

Took some of the leads off the firewall post, her starter motor is not providing a direct short, thankfully, but her starter solenoid positive lead remains earthed, as does her firewall post... Can't get my head around this one...

If I take a positive to the starter motor positive she should spin right?

Is it possible for a starter solenoid to fail in such a way so as to provide a direct short?

The engine is earthed.
 
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Old 07-23-2016, 07:59 AM
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Originally Posted by NathanDD6 View Post

Took some of the leads off the firewall post, her starter motor is not providing a direct short, thankfully, but her starter solenoid positive lead remains earthed, as does her firewall post... Can't get my head around this one...

Nor I

Are you getting lots of smoke from the post?

If the firewall post was actually earthed you'd be arc welding !

It would be the equivalent of holding the positive and negative battery cables together


If I take a positive to the starter motor positive she should spin right?

One of the heavy cables to the starter is the main 12v supply. If it's still hooked up to the starter (it attaches at the solenoid) then you've got your 12v supply.

The white/red wire from the starter relay also goes to the solenoid. It has 12v with the key turned to 'start' . It 'pulls in' the solenoid to activate the starter


Is it possible for a starter solenoid to fail in sluch a way so as to provide a direct short?

.

I don't see why not. Anything can happen...and an internal meltdown (so to speak) could cause a short-to-ground, I reckon.

But, you'd have smoke

Cheers
DD
 
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Old 07-23-2016, 08:16 AM
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I'm with Doug here.

Take a volt meter, switch it to Volts DC. Black probe to earth. Red probe to the battery cable at the TOP stud of the solenoid, you should see battery volts, so 12v.

Red probe now on the lower stud of that solenoid, you should see 0volts.

Now the tricky bit, Red probe to the solenoid terminal (small) that the Red/White wire attaches to, and get someone to turn the ign to "start". You should have 12v.

If you have 12v in that small terminal, and the solenoid is NOT clicking, then the solenoid has gone AWOL.

If the solenoid does click, and nothing happens with starter rotation, CAREFULLY place the Red probe on the lower stud of the solenoid again (the one you used for the 0v test above), and get that someone to go to "start", and when the solenoid "clicks" there should be 12v in that lower stud, and if the starter still fails to rotate, the starter, and/or the solenoid are at fault.

Whilst you are down in the depths check the cables that attach to the solenoid, as sometimes they can move slightly and short out, BUT, that will give massive smoke due to the short circuit.
 

Last edited by Grant Francis; 07-23-2016 at 08:18 AM.
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Old 07-23-2016, 08:18 AM
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No smoke that I saw, and her engine bay was open when I last ran her.

The firewall post, I don't know, but my volt meter is perhaps having a moment, as it also tells me that the post is positive 12v...

Her starter solenoid wire remains shorted to the engine, continuity regardless of the battery being connected or not.

Thanks for the explanation Doug, makes sense now, any chance I can reach these wires without removing the starter motor all together, maybe even if I just shift her a little so I can get my hands onto the front?

Anyone got pics of the starter motor, so I know what my fingers are touching down there?
 
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Old 07-23-2016, 08:20 AM
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Thanks Grant, your reply just came through as I hit send, the trouble is getting down there, there's a heat shield, how is it secured over the solenoid, I'll have to remove it.
 
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Old 07-23-2016, 08:30 AM
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Originally Posted by NathanDD6 View Post
No smoke that I saw, and her engine bay was open when I last ran her.

The firewall post, I don't know, but my volt meter is perhaps having a moment, as it also tells me that the post is positive 12v...

Her starter solenoid wire remains shorted to the engine, continuity regardless of the battery being connected or not.

Thanks for the explanation Doug, makes sense now, any chance I can reach these wires without removing the starter motor all together, maybe even if I just shift her a little so I can get my hands onto the front?

Anyone got pics of the starter motor, so I know what my fingers are touching down there?
That firewal post MUST be 12v as long as the battery is connected. There is a similar firewall post on the LH side. Sooooo, the +ve battery cable goes from the battery to the LH firewall post, then across the rear of the engine to the RH firewall post, which then has a battery sized cable going to the top stud of the starter solenoid.

The starter solenoid wire will show continuity if it is still connected at the solenoid. The coil windings inside the solenoid go to earth eventually. Continuity can only be checked if the wire to be checked is disconnected at both ends.

Remove the RH air cleaner assembly, then you will have plenty of room to reach in there. The studs and cables etc are all on the end of the starter and facing the front of the car. I dont have any snaps, sorry.
 
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Old 07-23-2016, 08:33 AM
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Thanks Grant, I'll have a go and report back.
 
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Old 07-23-2016, 08:36 AM
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This should help.

Starter heat shield.

V12 starter issues-v12-starter-heat-shild.png

Starter motor ans solenoid.

V12 starter issues-v12-starter-motor.png

That shield is 1 nut, #7 in that first drawing.
 
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