I hope someone has an idea about my situation.
I was driving the car then it just stopped (luckily I was not on a main road or freeway), I could not restart the engine, I tried turning it few times but it would not start, I had to push it into a parking space. Next morning I cranked it few times without luck in the end I tried one more time, it then started. It's been working since then but no answer as to why this happened, my mechanic changed the temperature sensor on the left side, I think it has to do with ignition control (not sure). (Lucas Ignition)
If anyone has an idea please let me know

Thank you.

 

Does it crank without firing? If so, could possibly be the fuel pump on the way out. If you have an in-tank pump (I think 1989 might still be external), open the fuel cap, have someone turn the key to position II, and listen for its whine. If you have an external, that's easy to replace. Fuel pump relay is another place to check. And I'm sure some actual experts will offer you better advice.

 

Thank you. I will check.

 

Hi HM10

1989 XJS V12 has an external Fuel Pump, so easy to change if needs be

The Coolant Temperature Sensor which your Mechanic Changed was very likely to have been the cause of the problem, as if this was faulty then the engine won't start, so looks like replacing that has now got that fixed

 

Couple things. Key on fuel pump cycle was a good tip, it tells you if the ECU is alive and thinks it's ok to start. If you can get a timing light you can clamp it around a spark plug wire and see if it flashes when you crank. That tells you if the spark system is ok.

There is also the fuel inertia cutoff switch right inside the driver's door hinge that may have tripped and needs to be reset. I don't think it would start occasionally if it is tripped.

 

Thank you for the tips.

The car starts regularly, this happened a couple of times before that was after turning the car off for ten minutes, then it started after a few tries and I had to keep the RPM up until it took off. This time I was driving when it shut down, it did not start soI had to keep it overnight, next day started after a few tries, I took it to mechanic but he could not see anything wrong and changed the sensor. Its working as usual now. I worry it would happen again.

 

If a Lucas car, I would hazard a guess that the ignition am is starting to fail when hot. If you want the car to be reliable, I would replace it.

 

I'm afraid you'll have to diagnose it when it happens. You can check spark very easily with this tool (Spark tester) . You'll have to pull a wire off a a spark plug and plug this in between the plug and the wire. It will flash to let you know that the speak is happening. It might melt the tester if you just leave it in place.

Was the car not starting when the mechanic looked at it?

 

What is ignition am

Thank you.

 

When the mechanic had the car it was starting normally, that's is the reason he had problem figuring out issue

 

That should have been amp. He missed the P. Otherwise known as an amplifier.

Jack

 

Then that's why you'll need to diagnose b it when it happens again.

 

Thank you.
I am going to change the amp. fro the time being.

 

I agree with all that has been mentioned.

HAve a read of my stickie at the top, No Start..........

I strongly suggest adding your car details via the CP tab at the top, and especially the LUCAS notation. This will help everyone with advice.

Good luck.