1983 Jag Xj6- engine shuts off odd and abruptly. Bad ignition switch maybe?

Howdy all,

So while messing with my ac relay I had the car on and idling great to test for blower fan activity. While that issue is discussed in another thread of mine on this site, my car did something unexpected. It just abruptly shut off. No starving for fuel, no clangs, no gut wrenching sounds or shakes, it just shut off as if i flipped the key. After that It took me 6-8 key turns to get it back on and idling, once again at a great pace with no fluctuations in rpms. It idled for 8-10min then died in the same manner again. To not risk more damage or killing my battery I have not tried to start it since.

I suspect the electric ignition switch, but was wondering how to test or if their might be other possible issues?

I can say all fuel injectors are new, pump works great, fuel filter is good, and i get fuel return to the correct tank. When i try to crank the starter engages normally. It just will not go.

Ideas?

Thanks!

**
In short, Nikolas - it cranks but wonā€™t start?

If so; jumpwire from battery ā€˜+ā€™ to coil ā€˜+ā€™. This will bypass the ignition key - just to see what will then happen. If this does not eliminate the problem - it gets more interestingā€¦:slight_smile:

Just keep your battery chargedā€¦

Frank
xj6 85 Sov Europe (UK/NZ)
**

Yes sit cranks but has trouble starting. Ill try you idea this afternoon.

Aye, that is my favorite. Jump 12v to coil +.

Another. when it quits. Get the meter or test lamp. With the key on, probe for volts at coil +.

Iā€™ve noted the You tube mechanics have neat probes for _ or - !!!

All beat he way we did it way back. + to ground to get a spark!!!

Carl

Carl

So I just found out from my Grandfather in-law (original Car owner) that the ignition coil on the car is the coil from the dealership in 1983ā€¦ So i tried jumping as you all have said nothing happened. regardless of it it is the coil being the issue or not, I do believe its time for a replacement. Ill report when the new coil comes in next Tuesday or Wednesday and I can get it installed!

**
That the engine quits instantly when it quits does indeed imply an ignition failure, Nikolasā€¦

Connecting a spare spark plug to any plug lead, is the common ign test with a non-start. No spark while cranking, no ignition - but the cause may be variousā€¦

But the jump says your ign key is not the problemā€¦

Frank
xj6 85 Sov Europe (UK/NZ)
**

Nikolas,

donā€™t rush it! Iā€™ve replaced what is likely the original coil of my 1975 car just last week and Iā€™m not even sure whether it is broken. Chances are you bin a high-value original Lucas part for a low-quality and cheap replacement part with a fancy name and brighter color ā€¦

My money would be on the spark as well, but the ignition lock is safe for me, as you write that you operate the starter right after it stalls. If the ignition lock is failing, the starter wonā€™t turn, even the relay wonā€™t click

You have to try 6-8 times for a restart? Then address spark! Have you checked dizzy cap, contacts and HT wires? Sudden death also indicates either power out (intermittent loss of +) or intermittent loss of ground. Check all ground connections - also a standard remedy for all kinds of electric issues ā€¦

Good luck

Jochen

75 XJ6L 4.2 auto (UK spec)

So changing the coil did not lead to the car running again but it did help me confirm a bad distributor cap. will be changing as soon as I can get a new one!

So spark from the coil wire, but not to any spark plug? Brilliant, very happy for you!

Yep! Made me happy too

Nikolas Faust,
Fighting Texas Aggie Class of 2019

So looks like my distributer is stuck. Is it more time efficent to just buy a new one and slap it in (only because it seems like the common price for one is 50 bucks on ebay) or is it better to try pulling it, cleaning, and putting the original back?

If cleanings the way to go does some one have link to a step by step video or guide for dummies lol!!

Thanks!

Nikolas,
What do you mean by ā€œthe distributor is stuckā€? I donā€™t understand how it could get ā€œstuckā€. Are you saying that the distributor doesnā€™t rotate when the engine is cranked?

Paul

Yes thatā€™s a better description. I guess you would say in better terms that it is siezed.

Nikolas Faust,
Fighting Texas Aggie Class of 2019

Hard to imagine what would break or make the drive shear, please pull that thing out (the bolt that goes through the bracket into the block) and have a close look.
If it doesnā€™t rotate when cranking something has gone horribly wrong - or it popped up and is no longer engaged; can you turn the rotor by hand?

No canā€™t turn by hand. Ill pull it out later this after and see.

Nikolas Faust,
Fighting Texas Aggie Class of 2019

After it cools down does it RESTART?
If so go straight to the spark box/ bad diodes
Everyone is right, chack spark at the plug instead of ripping everything else apart.
IF YOU HAVE SPARK ITS FUEL, i DOUBT
Good luck, the spark box is very common after 3 million miles and 40 years of service.
gtjoey1314
A seized distributor? I doubt unless it was a petronixā€¦inside joke.
Its keyed one way and to the oil pumpā€¦go back to spark box.

Gotcha will do.

Nikolas Faust,
Fighting Texas Aggie Class of 2019

When you say ā€œspark boxā€ do you mean ignition control module? The 1 ish inch thick black box that the electrical component of the distributer plugs into and that also has positive and ground cables going to the ignition coil?

I was also suspect of this but was not sure of its role in the ignition procedure of the car so i did not want to replace or mess with until it was identified as an issue. I know the plug on the module that goes to the distributor was corroded ( I have cleanded it now, it still has a no start). If thatā€™s a more likely culperate than the distributor to cause my no start issue. I can focus on it.

I only used the term ā€œstuck distributerā€ originally because i was not sure how else to describe whatā€™s not getting fire into my plugs, and because the rotor is currently not turning when I turn the key and turn over the engine.

Nikolas Faust,
Fighting Texas Aggie Class of 2019

Ok, your not stuck, you have no firing, from what your almost trying to say.

  1. forget EVERYTHING and do thisā€¦
  2. put everything back where it was as if you were going for a drive.
  3. pull 1 spark plug and see if you have spark, either by a spark plug adapter tool or some one holds it close to the head.
  4. No spark, go to the module and replaceā€¦that box just unplugs, its the brain in a way for the distributor .If you have spark its something else.
    good luck
    gtjoey1314

Thanks so much for the advice.

Being the start of this issue was the car just shut as if i turned the key off. NO grinding. NO whining. NO terrible sounds or shakes. Just a smooth, non intentional power down (It was also running great and idling when this happened.) Iā€™m not inclined yet that something on the gear end of the distributor is sheard.

But after i do some checking we will see

Sorry for the bad descriptions of the issue everyone. Thanks for trying piece it all together!

Nikolas Faust,
Fighting Texas Aggie Class of 2019