Intermittant starting problem

[bryanharper57850]

Am seeking some words of wisdom from some like minded people please!
My Jaguar will start, run fine, everything working, no problems.
Then having stopped and switched off, turn the ignition and nothing happens (save for all the dash lights come up as normal).
And, to make it worse, it is intermittant - sometimes it happens, sometimes it doesn't.
So far, always starts again if left for a period. But not much good when you've stopped at a filling station or outside the shops!!
Any suggestions gratefully received.
Thank you.

B.

[Dave Eynon]

I had a similar problem with our VW T5 (auto) which I eventually traced to be caused by the starter motor. I fitted an exchange unit and problem solved. Not a Jag I know, but some things are the same whatever the make. The fault started at a very young age / low mileage so I lived with it for ages thinking it was gearbox inhibitor switches etc. A bit expensive though if it turns out not to be the root cause.

[bryanharper57850]

Thank you Dave, appreciate your thoughts. Everything helps!
I had exactly the same on an old Freelander and that was fixed with some wizardry in the steering column and the addition of a push start button in same. Since it was done, I have never had to use it.
I will invetsigate what you say, and report back!
Thanks again.
B.

[andypryce]

If nothing at all happens, not even a clicking noise, then likely to be starter solenoid rather than the starter motor, if you get a repeated clicking noise that is the solenoid trying to activate the starter, in which case it is either starter motor or poor battery. Many are combined as one unit I believe. Looks like SNG Barratt do one for the XJ40, would be worth replacing that before replacing whole starter motor.

https://www.sngbarratt.com/English/#/UK ... eBranch=UK

[bryanharper57850]

Thanks Andy, very useful!
Yes, no clicking or sound at all. I will be looking into what you say.
Thanks again.
B.

[ptjs1]

Bryan,

If there is no clicking from the solenoid, I would start by looking earlier in the circuit. Look for an output from the starter relay upon cranking. It may be that the relay or relay holder is losing integrity when it's warm.

Also check that the autobox rotary switch is functioning correctly and not stopping the starter circuit. If it fails to turn over, try putting it in Neutral rather than Park and see if it makes a difference.

Also, when it fails to turn over, check that the brake lights are working. I believe that the CPU will prevent energising of the starter relay if the brakelight circuit switch is failing.

Good luck

Paul

[bryanharper57850]

Thanks Paul for your thoughts. Will be checking these things out!!
B.

[bryanharper57850]

Have had to wait a bit for the fault to manifest itself again. But, did so again today, this time from cold, and which is a change. Anyway, tried putting into neutral as you suggested Paul. And it worked!
So, gives me something solid to go back to the garage with now.
Thanks to everyone who has responded to my initial post. First time I have used the forum, and am really grateful for the collaboration.
I will share the outcomes as I go through the fixing process.

[ptjs1]

Bryan,

It sounds like

a. you might now have some form of contingency to get the car started when the problem arises
b. it seems like the rotary switch or it's wiring, or the selector lever might well be the first place to start investigating the cause of the problem.

Good luck getting it sorted

Paul