Jaguar XK8 turns and won't start - no spark - Solved... kinda
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I haven't still. I told the mechanic to get the car out in the cold and wait for it to stop starting, again 
and they are gonna test it. But I don't think that is the case, because as far as I know it should cut the fuel too, which is not happening.
and they are gonna test it. But I don't think that is the case, because as far as I know it should cut the fuel too, which is not happening.
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So... We got the car out of the garage and 2 nights later it again stopped starting. So there is definitely a temperature component to this issue. I did a quick test by taking the ECU back home with me and letting it get to room temperature (23-25C) which is way more that what it got inside the shop. But it didn't work. I did assume so as the spare ECU didn't work also and the chance of both having the same issue was slim, but still.
When taking the ECU I forgot to test the inertia switch as I though the mechanic already did it, when I asked him like 5 times to do it
But when the ECU test failed I tried the switch.
It still doesn't make full sense, but I think it might be the switch. If I am reading the manuals correctly if the switch is up it is tripped. But as I said I do hear the fuel pump working and have checked the fuel pressure. Also the car locks and unlocks fine, which I also read shouldn't be the case with the switch tripped.
But the switch was up
Also I couldn't get it down. Tried even starting the car with the switch pressed, and all other combinations. The most I got to was 1 hiccup, which gave me hope
Now I am gonna go try take the inertia switch from my donor car, if the other mechanic hasn't left the guard dogs unchained, and the car is unlocked Otherwise I will take it tomorrow and try swapping them.
When taking the ECU I forgot to test the inertia switch as I though the mechanic already did it, when I asked him like 5 times to do it
But when the ECU test failed I tried the switch.It still doesn't make full sense, but I think it might be the switch. If I am reading the manuals correctly if the switch is up it is tripped. But as I said I do hear the fuel pump working and have checked the fuel pressure. Also the car locks and unlocks fine, which I also read shouldn't be the case with the switch tripped.
But the switch was up
Also I couldn't get it down. Tried even starting the car with the switch pressed, and all other combinations. The most I got to was 1 hiccup, which gave me hope
Now I am gonna go try take the inertia switch from my donor car, if the other mechanic hasn't left the guard dogs unchained, and the car is unlocked
Otherwise I will take it tomorrow and try swapping them.
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From: Spencer, NC
Kainy, that looks just like the Ford switch I put on my Triumph Spit6, even the same plug. They should just push down with no problem, so maybe you will have better results with the replacement .
Good luck.
Wayne
Good luck.
Wayne
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Weirdly enough the spare one from the other jag, also does not click in place when pressed. Is this something that happens only when the ignition is on or something? I am still going to replace it, just have to move from the one shop to the other
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No luck 
Acts the same way, and the switch doesn't stay pressed. I might be operating it wrong, thou. I don't know. I did get couple of more "hiccups" (always only 1 per try), but nothing more. I will probably move the car tomorrow to a more specialized shop.
Acts the same way, and the switch doesn't stay pressed. I might be operating it wrong, thou. I don't know. I did get couple of more "hiccups" (always only 1 per try), but nothing more. I will probably move the car tomorrow to a more specialized shop.
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The engine coolant temperature sensor is also absolutely fine. Gives 5.2kOhms with 2C outside (5.9kOhms should be at 0C). When I short the plug it goes to “H” on the dash, so the wiring is fine, too. Still no start. Will be checking if any fuel gets inside the cylinders now. But I am running out of ideas
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We were barking at the wrong tree. There is negative signal on the coils. The injectors do not have negative during turnover. They get one pulse on ingnition start and one on cut off
I then started heating up with a heat gun the security module in the trunk. More pulses appeared But it couldn’t start. Tomorrow I will bring my spare security module and hopefully it will fit.
what else can be cutting off the injectors?
I figured out the inertial switch and it is not tripped - to plates pop up and the button puts them back together, while it stays always up.
I then started heating up with a heat gun the security module in the trunk. More pulses appeared But it couldn’t start. Tomorrow I will bring my spare security module and hopefully it will fit.
what else can be cutting off the injectors?
I figured out the inertial switch and it is not tripped - to plates pop up and the button puts them back together, while it stays always up.
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I don't think fuel pressure is available over OBD on a 97??
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It is available. If I remember correctly it was 3.7-3.8. Also the mechanics checked it manually at the rail and the pressure is fine. The ECU is not telling the injectors to fire. As I mentioned there is a single pulse on the negative wire (hardly seen on the video) when the turnover starts and one more when ignition is switched off.
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Sadly, no real progress has been made yet I do have only may be a month left to find a solution for this, as March the temperature will start staying consistently and rising above 10C
The latest update is not very promising. The car is at the local Jaguar dealership, and has been there for more than a month now. They did actually work on the car only for the past 2 days, thou
Still what they could only confirm for now is:
1. The ECU is not sending ground signal to the fuel injectors - no idea why
2. The ECU is not sending ground signal to the ignition coil relay - no idea why (the original issue of this thread, circumvented with ground from the body)
- once the coils are powered up through the relay, they do receive ground signal through the Ignition modules and are being fired up while cranking with seemingly correct timing
3. The car does start normally 1-2 hours after being taken inside a garage
4. They cannot find out if the car has a transponder module or not
- their current dealer diagnostic tool is not particularly good with older jaguars - basically works only for the ECU and TCM. It does not detect a transponder module
- their software claims all European cars should have one, where the US one don't (97' car).
- they are waiting on an older Ford dealer diagnostic tool to hopefully read more stuff
5. The crank shaft sensor was changed, but nothing changed.
Still the question remains - what can be telling the ECU, not to fire up the injectors and coils, but still crank the engine? And then when the temperature rises to start working (possibly due to bad ground connection?)
I do have only may be a month left to find a solution for this, as March the temperature will start staying consistently and rising above 10C The latest update is not very promising. The car is at the local Jaguar dealership, and has been there for more than a month now. They did actually work on the car only for the past 2 days, thou
Still what they could only confirm for now is:
1. The ECU is not sending ground signal to the fuel injectors - no idea why
2. The ECU is not sending ground signal to the ignition coil relay - no idea why (the original issue of this thread, circumvented with ground from the body)
- once the coils are powered up through the relay, they do receive ground signal through the Ignition modules and are being fired up while cranking with seemingly correct timing
3. The car does start normally 1-2 hours after being taken inside a garage
4. They cannot find out if the car has a transponder module or not
- their current dealer diagnostic tool is not particularly good with older jaguars - basically works only for the ECU and TCM. It does not detect a transponder module
- their software claims all European cars should have one, where the US one don't (97' car).
- they are waiting on an older Ford dealer diagnostic tool to hopefully read more stuff
5. The crank shaft sensor was changed, but nothing changed.
Still the question remains - what can be telling the ECU, not to fire up the injectors and coils, but still crank the engine? And then when the temperature rises to start working (possibly due to bad ground connection?)
Last edited by kainy; Feb 1, 2019 at 03:51 PM.
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The crank sensor is reading out the RPM properly. I did have a spare and made them change it anyway. I did gave them the cam sensor to but forgot to ask if they tried changing it too. Still both are reading out fine on the diagnostic tool. I will however, ask them to double check
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The live data seems fine. If I remember correctly it is registering 150rpm while cranking.
I just spoke with the mechanic and his next step is to look into the transponder module if the car has one. If she doesn’t than the starter has some input in talking with the ECU instead of the transponder module basically registering the use of the correct key.
also he noticed that the key barrel is not locking back properly after the key is taken out and if hit lightly will click/lock? back.
Also, fingers crossed, he will try to reset and update the gearbox, as officially jaguar is not doing that on older cars now/doesn’t support them anymore not related, but can be one good thing to happen to it in the past three months
I just spoke with the mechanic and his next step is to look into the transponder module if the car has one. If she doesn’t than the starter has some input in talking with the ECU instead of the transponder module basically registering the use of the correct key.
also he noticed that the key barrel is not locking back properly after the key is taken out and if hit lightly will click/lock? back.
Also, fingers crossed, he will try to reset and update the gearbox, as officially jaguar is not doing that on older cars now/doesn’t support them anymore
not related, but can be one good thing to happen to it in the past three months
As for the key transponder if you look in and up at the drivers side fuse box in the fascia you can see the plug for the transponder. It would seem to me that if your car is not equipped with an exciter ring at the key cylinder then you do not have one. As for the clicking after your key is removed that is the gate for the key that is sticking open just spray it with a good lubricant and work the key in and out.