Can't start the car

Hi there,
My 1986 XJ6 can’t start… When I turned the key all the way the car sounds like when you shift to Drive and try to start the car, but I have already put it to park. The oxygen sensor is on, and the emission is trying to pull gas out (try to find a better way to describe it but basically it’s just like you put it on d and start the car). I have a video but unfortunately I don’t know how I can share it here. It happened before but it went away and ran well for a while up until now so I don’t know what to do with it… I just changed the battery and the alternator was fine. Tried to jump start the car but it didn’t work either.
Anyone who has any lead or know what to do with it? Thanks guys

In ‘Drive’ the starter relay is disabled, Keith - the starter will not run to crank the engine. Ie is the problem that with the ign key to ‘crank’, ‘all the way’, there is no cranking? Clarify…

If so, there are six possibilities; ign key failure, start inhibit switch failure, failed connection between switch and ground, starter solenoid failure, starter relay failure - or starter failure.

Locate the starter relay - then we can tell you what to do…:slight_smile:

xj6 85 Sov Europe (UK/NZ)

Engine won’t crank checklist:

Engine cranks but won’t start checklist:

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Have you checked the inertia switch?

The inertia switch will not interfere with cranking, Aristides - except that later V12 did indeed have this feature. However, the inertia switch certainly will prevent starting…

xj6 85 Sov Europe (UK/NZ)

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Make sure it’s in P so you don’t run yourself over and jump power directly to the starter solenoid. If that gets her going it’s got to be the neutral safety switch or the relay on the bulkhead.


Really? I can not speak for the V12. I can speak for my two present cars. If the sifter is in any position except P or n, the engine can noyt be carnked.

teh inhibittor s at the shifter. It governs the ground leg of the start relay.

Carl si

My loump has an emergency crank wire in the engine bay. touch to battrry + and it will crank. And as you say, must be sure the trans is in either P or N!!1

Decades ago, the inhibtor in my IHG went bonkers. I jumped it. for decades my reflex id to put the trans in neutral, then cran. it worked, no surprises…

The inertia switch only kills the fuel pump, not the starter; the neutral safety switch gives ground to the starter relay so it only disables the starter (although I believe the starter relay also powers the pump? But that doesn’t matter here)

I ran over my foot once. No start. Jumped to the solenoid as you said. Instant start, had to run after it once I had my foot back!


Inertia switch, not inhibitor. yu, fuel mpump, not starter…

In souta delete my miseading post.


that sounds very much like the inhibitor switch at the shifter quadrant - I think the V12 works like the XK in this respect. Before you turn anything apart and get your hands dirty, keep the patience and check out the wiggle factor moving the shifter, maybe even pressing the shifter high up in P while you turn the key to provoke contact. If you confirmed that it is just the inhibitor switch, remove the shifter quadrand, fix, i.e. relocate, the switch. It seems to get moved over time.

Good luck


75 XJ6L 4.2 auto (UK spec)

Certainly, Carl - the start inhibit switch, working correctly, is there to break starter relay ground, preventing cranking in any gear. Function can be tested at the starter relay…

And added feature on the later V12s also positively prevents cranking if the inertia switch is tripped - a bit ‘belt and braces’…

xj6 85 Sov Europe (UK/NZ)