Hi Jomo

Could be a Key Fob problem, as I believe you said you lost it and so you would probably need it to disarm the immobilizer

Can't offer you any other solutions until you have found that

 

I ordered another FOB.
I found this on the forum: The Check Engine Light (CEL) is output by the ECU. If this does not remain illuminated after the other dash lights go out when the ignition is turned on then the car is immobilized and will not crank or start. When the ignition is switched on the ECU will perform a number of checks (I don't know the detail or sequence) and security is just one of these. If any of these checks fail the CEL will not be illuminated at the end of the sequence.
Now since my car cranks does this rule out the immobilizer being the problem?

 

Hi Jomo

I have absolutely no idea but I wouldn't rule out that Blue Relay under the Dash, try and find a Silver one just like it and also check if that Relay has a diode

That is what got my Car Started, when everything else had been tried and failed but if you're not getting a Spark at the Plugs, then maybe it is the immobilizer but that is just an educated guess

 

Just as a matter of interest, If you connect the 2 yellow wires together in my picture of the alarm connector, the alarm will auto arm after a few seconds of closing the door. FYI

 

Hi, Let's get something clear. I am asking for free help from a forum of volunteers. I really respect what goes on here. I assure you (everyone who is reading this) that I will try and have tried everything that I am asked or will be asked to try.
To OB, yes I have cleaned the relays, switched the two relays and have actually tested other relays in both positions but there is still the no start condition.
Thanks for every ones help

 

I will look into this tomorrow. Thanks!

 

Hi,
Can someone explain to be how I can check to see if I have fuel getting to the rail? I have a 4.0 engine.
Thanks

 

Hi Jomo

That is very easy

Disconnect the Main Fuel Pipe where it goes into the Fuel Rail (Using 2 Spanners not 1) as you need to counter torque it when you undo it to avoid any damage to the fittings (Ignition OFF)

Petrol will leak out regardless so have a rag to wrap round the joint as you undo it to soak up any Fuel

Just because Petrol will run out, don't take that as any indication that Fuel is getting to the Rail as this is just residual Petrol that was left in the Fuel Pipe

Then get a wider piece of Pipe anything will do and slip it over the rubber Fuel Pipe that you just disconnected from the Fuel Rail and then just drape this now extended Fuel Pipe over the Front Wing/Fender into a Container

Then when you turn on the Ignition, Petrol should come zonking out of that for about 3 Seconds

Do Not Attempt to Start The Car! (only turn the Ignition Key to position 1)

If Petrol comes shooting out of that Pipe, then this will show that had it still been connected Fuel would have been getting to the Fuel Rail

Take all the usual precautions with Fire Extinguishers standing by just in case

But if it were me then I would be looking for a Spark First rather than any Petrol getting to the Fuel Rail

You can see how I did this on Page: 55 of my 'Cherry Blossom' Restoration thread and here is the Link to that page

How I checked for Petrol getting to the Fuel Rail of my XJS 4.0L AJ16 Engine

Also Check out the previous pages Page: 93 and 94

Warning! only attempt to do this Outside in the Open Air and NOT in your Garage or Shop

 

My car is in my garage. I really can't get it outside. Any other suggestion?

 

Hi Jomo

Too dangerous to do this in the garage with all those Petrol Fumes about and so instead I should concentrate on getting a Spark at the Plugs

As long as you can hear the Fuel Pump running, in the way that you normally would then I very much doubt if Fuel will be your problem

 

1. jomo, I have two 1995 convertibles with the 4.0L. I am going to share with you the most common cause of a no start on the AJ16. I had the same thing happen on my red XJS. Ran fine, shut it off and next time cranked but would not start. There was a great deal of misinformation when this happened on the forum as I was told if the tach was moving when I was trying to start the crank sensor was ok. I checked all the basics and trusted my instincts and pulled my known good crank sensor off my other XJS and put it on my red XJS and the car started right up.
2. You are lucky in that you have a 1996 XJ6 so my suggestion is pull that crank sensor off and test it on your XJS. If it works problems solved and if not you will have eliminated that possibility. The magnets get weak over time so not just a mileage issue. If you decide to do this pull the crank sensor on the XJS first so you learn how to get it off and how to take it apart at the connector. The CPS is very easy to get off and you will see it mounted next to the crank pulley as it is reading the signal off the crank pulley. I think it has one wire feeding into it and is held on by one or two bolts on a small bracket. I jacked my XJS on the right side and put a jack stand under the right side cradle as the crank sensor mounts to the right side of the crank pulley area as I remember.
3. Let me know if you have any more questions on this but this is where I would start. The crank sensor runs about $65.00 or so on Ebay so not a big Expense if that is your problem. Here is a link for one on Ebay and I would study the photo of it to see how the connector is holding the male side going into it : https://www.ebay.com/itm/For-1992-19...oAAOSwNOxbnz0X

 

I was thinking about doing just that!. But you suggesting it will cause me to do this first thing tomorrow. It will be great if this works. Thanks for your support!

 

I do have a few questions. If I remember correctly the plug end of the crank sensor is also bolted down to the engine. Can you tell me how many bolts there are? Also after doing this job do you still think it is best going from under the car rather than from the top of the engine? Can you see all the bolts that need to be remove and how long did this take you?
Thanks!

 

Hi Jomo

In the event that you decide to replace the CPS (Crank Position Sensor) then don't attempt to do it from underneath the Car or you could be there all day (ask me how I know or rather don't!)

But if you tackle this Job from on Top you can do it in less than 5 minutes (I did it in much less than that) unfortunately for me it was £50 wasted, as it turned out the Blue Relay was the problem but there you go!

Anyway lest I digress:

The CPS is held in place by one single bolt but getting in the way of that is a push together plug, that I found a Nightmare to undo

But this Plug is fixed to a Bracket which is held in place by 2 bolts, so I found it much easier to unbolt the Bracket while this Plug and Socket were still attached to it, which then gives you much more slack to unplug it

Although you need to be Careful here, as just behind that Bracket is a 'Blanking Plate' that can very easily come off and fall on the ground without you even knowing that its happened

So when you put the Bracket back, be very sure this Blanking Plate is put back in place or you will have Oil Leaking everywhere but once that Bracket is out of the way, then you can get to the CPS that is held in place with one bolt

Its pretty much impossible to see what you are doing although you do not even need to remove the Top Hose

So its more a question of taking a look and remembering what you have seen, then putting you hand down that very small gap with your Spanner and then undoing those bolts

This job sounds a lot worse to do than it actually is and is in fact so easy once you get the hang of it, that if push came to shove you could easily do this job by the Side of the road

When you put it all back together, don't over tighten those bolts as if one happens to snap off then you will have one hell of a big problem to sort out

I've done a Step by Step guide on how to Change the Crank Position Sensor (CPS) complete with all the Photos on Page: 94 of my 'Cherry Blossom' Restoration thread 'Carmen won't Start'

Click Link: Below

How to change the Crank Position Sensor on an XJS 4.0L Engine Page: 94

 

I had the strangest feeling today when I did not want my xj6 to start. I had a strange feeling in my stomach because I always want my xj6 to start but today I did not want that to happen!
Well as you probably know my xjs is not starting and it was running just fine the last time I drove it.
LuvmyXJS' just insisted that I swap my cps between my xj6 and my xjs and after doing that the xj6 did not start. Now that was a great feeling knowing that the sensor was bad. So I just had to put the sensor from my xj6 into my xjs and it started. Yeah! Then I had to take out the sensor from the xjs and put it back into the xj6 all the while making sure I did not mix up the good sensor. The good news is that the xj6 started right up with its own sensor!

A few comments I want to make. I did all the work from the top. First there was this stupid solid pipe in the xjs (but not in the xj6) that made it seemingly impossible to get to the bolt to remove the sensor without removing the upper hose. So I removed the upper hose. In both cars the single bolt came out easily. Both plugs disconnect rather easily. Now getting those plugs off the ***** brackets was the biggest pain in the whole job. In the end I realized that it only took about 5 minutes (4 for the xjs and 1 for the xj6) to get the plugs off it brackets. I guess knowing that it should have taken about three seconds for both cars was getting to me. All in all yes you can easily do this on the side of the road. Just have a long extension and an 8mm socket.

1 last thing. I do not know how to check a cps at all, but I do know one thing- If the tach does go to about 200 when starting the car it does NOT mean a thing! My car did this AND it had a bad sensor. Possibly if the tach doesn't move then the sensor may always be bad, but if the tach does move you gained no information regarding whether you have a good or bad sensor.

Thanks for every ones help, especially LuvmyXJS'! I will order the new sensor and report back with the results.

 

Hi Jomo

The Tacho moving is not meant to be a definitive Test, its only an indication of what might be

 

Great to hear you found your problem. Always nice to have a good CPS to test and either fix the issue or eliminate the possibility. The CPS failing as yours did is enough of a issue on the AJ16 that many of us in the know carry a spare with us just in case. As I stated this does not seem to be as big of a mileage issue as a time issue as the magnets get weak and without warning work and then next time simply do not.

Most importantly is getting the word out that if your tach moves when you are cranking does not mean the CPS is good. Years ago when it happened to me the vast majority thought that this was the case but I thought it very strange that it ran fine and then next time cranked over but would not catch without any prior drive ability issues . The CPS is not always the problem but many many times it is simply the CPS has stopped reading the signal off the crank pulley.

Keep in mind that there is a vast amount of knowledge on the XJ6 forum relating to the 4.0L AJ16. Many times when I have been stumped on something related to the AJ16 I have found my answer in discussions related to the 95 to 97 XJ6. There were many more XJ6' produced and many more driven every day with high mileage compared to the XJS so more feedback available at times on the XJ6 forum.

I am happy to know that you can get the CPS switched from the top side as who knows might have to put my spare on one day in a parking lot after dinner etc.

 

OB, that is just my point. If the tach test isn't definitive then what good is it. Now if it said that 90% (or some other percentage) of the time if the tach moved that meant that the cps was good then that would mean something to people.
It just seems that on the forum it says that if the tach does not move you should really check your cps and if it does move then check for something else. It is just my opinion but I feel that as a forum we all could do better with this.

 

I found the cps for dirt cheap ($21!) on amazon. If this works I will get two more to keep one as a spare in each of my Jaguars! Here is the link to amazon.

 

I got the sensor today (6 days earlier than expected and two days after ordering it) and literally had it installed in 3 minutes(30 seconds to bolt it down, 2 minutes to get the plugs connected (and I have very small hands) and another 30 seconds to pin the plug to its mount)
The car is driving well. Unfortunately the cel is on and I guess it is because of a (previous) bad cps sensor!