Hello,
This is my first time on this forum.I have a big problem.The engine dies while driving. After that, when trying to start it, all I could hear was a ticking sound from the pump relay and EGR valve. The starter turns the engine over, but it doesn't start, The technicians checked everything, but they didn't solve the problem.Has anyone had such a problem?
Please help me
Thank you very much

 

When you try to start it after it has died, check for:

1. A spark, and
2. fuel spraying from the injectors.

That will give us a place to start the diagnosis.

 

Kpetras,

As Greg has said, you either haven't got spark at the plug ends or fuel coming out of the injectors when the engine is cranking.

You mentioned that the technicians have "checked everything". But if they haven't told you which of the two conditions above aren't happening, then they clearly haven't checked the very basic 2 elements, That's very disappointing if they just haven't checked the obvious. It doesn't sound as if they don't really understand the XJS or it's electrical circuits.

I would start with some basic diagnosis in this order:

1. From ignition off, get someone to turn on the ignition to Pos II and listen to see if the fuel pump immediately starts buzzing. It will only run for about 2 seconds so be in the boot and able to listen for the pump IMMEDIATELY the ignition is turned on. If the pump runs briefly, go to Test 2. If the pump doesn't run for this short period of time when the ignition is turned on, then you have a fuel pump problem. It could be the relay or it could be the pump. Go to Test 3,

2. From Ignition Pos II, turn to Pos III to start the car, and check that then pump runs again whilst the starter is operating. If the pump doesn't now run, you possibly have an ecu signal problem.

3. If the pump didn't run in Test 1, check for voltage output from the fuel pump relay on Terminal 87 - the Blue & Red wire on the relay holder. If no voltage output when the ignition is immediately turned on, then check the rely mount in the holder. If it seems ok, check that there is voltage into the relay holder on Terminal 30 - the Brown & Red wire. If you see voltage in but not out, then change the relay. If you don't see voltage in (unlikely), that implies a failed input which is unusual. If you have voltage in and out on Term 30 & 87, then check for voltage at the wiring plug of the pump where it enters the tank (you need to strip the boot trim etc out of the boot. If you have voltage there but no pump running, then it sounds as if the pump has failed.

4. If you have the pump running on Ignition on and then again when the starter is operating, then pull a spark plug and conform that the plug is sparking when the starter is operating. If it doesn't, again you possibly have an ecu signal problem.

With the symptoms you described of the car just dying when driving and then not restarting, I wouldn't think it's a failed ecu. Far more likely to be something else such as a crank sensor.

Good luck, let us know how you get on. Don't change anything unless you've diagnosed that it's the problem. Otherwise, you'll be chasing shadows.

Cheers

Paul

 

Thank you very much for your response.I'll try to explain in more detail what's in my car.When the ignition is turned to Pos 2, the fuel pump relay and EGR valve start to rattle.It means that the fuel pump relay and EGR valve are not turning on normally.They turn it on and then turn it off again.They seem to have weak voltage.The 12V voltage is good and the starter turns over perfectly, but the fuel pump does not work because the fuel pump relay is not working.Maybe it's an ECU problem?

 

Have you tested for 12v into the fuel pump relay and if so, tried replacing the fuel pump relay?

 

I replaced the fuel pump relay, same result.But the EGR valve is not working either.

 

The fuel pump relay has 12 V

 

Does it have 12v on Term 30 with Ignition on? What voltage does it have on Term 87 when it is cranking?

A failed ECU is not a common problem. Especially as the problem happened whilst you were driving.

Paul

 

I'm out today. I'll check everything tomorrow and let you know then.Thank you very much for your efforts to help.

 

Before you do ANYTHING else, check the Heated O2 sensor fuse.
I had what appeared to be the same problem in my 94 XJS 6.0 and could not find the problem.
This issue lasted me over 6 months until a Jaguar Master Mechanic went home and studied the wiring diagram.
Next morning he told me to check the fuse that was in the boot.
The fuse was dead, and the replaced fuse solved the issue.
I'm not even sure if the 4.0 has the same electrical components but you would save yourself a lot of replaced parts.
ALWAYS check the easiest/cheapest things first.

 

Good day everyone,
I am writing about the measurement results.
Pin 30 of the fuel pump relay receives 12V directly from the battery even without the ignition on. Pin 86 receives 12 V when the ignition is turned on..When the engine is cranked, pin 87 receives 3.0V (it should receive 12V).Between pin 85 and ground it shows voltage pulsation from 6.72V to 11.81V (in my opinion the resistance should be 0). My understanding is that there is a bad signal from ECU contact LI 189-19. What could influence the emergence of such a signal?
I have checked all the fuses and they are all good.

 

I'm assuming you've pulled the ECU to check for corrosion, which is a common problem. You'll see some crusty green stains.

 

Good day everyone,
As I understand it, there are no other opinions, do I need to look for another ECU? Although when I open the ECU, I don't see any signs of corrosion.Do I need to look for exactly the same ECU, LHE 1410 DD or could it be some other last two letters? Or maybe try to repair it? Could you recommend someone who could do this in the UK?
I am waiting for any information.
Petras

 

Petras,

Before you condemn the ecu, I would:

- Confirm that you have a spark plug actually sparking when the engine is cranking. Remove a plug, earth it against the block and actually confirm it is sparking when the engine is cranked.
- Check the output signal from the ecu to the fuel pump relay is 12v from L189-19. Check it at the output pin of the ecu, not just at the relay.

Good luck

Paul

 

Paul,
There is no spark in the spark plugs. Contact LI189-19 must give a negative signal for the fuel pump relay to operate. The 12V relay receives 86 contacts. It produces a pulsating voltage (6.7-11.8V), measured at pin 85 and pin LI189-19. The resistance between pin LI189-19 and pin 85 is zero.
Petras