Since cold increases resistance and hotter temperature decreases resistance, I would check the connector that plugs onto the crank position sensor at the front of the bell housing at the bottom and clean the connector. Take the torx screw out to remove the sensor to inspect the condition. The connector and the visible part of the sensor are black in color on my 99. There is an additional sensor at the rear of each intake (upper)cam on the inside of the bank with the connector close to the throttle body. All three send signals to the ECM that affect the ignition.


Just my opinion, but since the very cold weather coincides with the start of your problem, I think the weak spark is due to high resistance causing a weak signal, causing a weak spark. The question is which connection. Clean the ground connections as well as has previously been suggested in this thread. These circuits are very sensitive to voltage changes, so a small voltage change can cause a lot of trouble.

 

Do you have a spare key?


See if it will start with the spare key. The key has a chip in it and can abruptly fail. That happened to my friend. He took a long trip and when he returned home, he could not restart the car. It started with the spare key.


So, rule that out since it was such a weird occurrence.

 

Actually, resistance of a conductor increases with temperature.

 

Although I disagree with Mike about the resistance as a indirect function of temperature; his point about the key is well taken. I had that problem: would not start with one key, but would with the second. Needed both reprogrammed.

I do agree weather is playing here, somehow. Maybe the temp sensor is failing to tell the ECU to enrich for cold start.

but yours is cranking, correct. Tends to indicate it is not the marriage of the chip in the key and the ignition ring.

Still, no harm in cleaning the sensor connectors.

What did you fine when you checked the tensioners? Still too cold?

 

Looked at every connection today, ran all my tests over again.

Finally got really angry and went old school. Got some starter fluid and made it run on that. Eventually cleared out and ran on its own. After it got up to temp I took it to the gas station put in some dry gas and filled it up.

Drove it about 20 miles and started it a couple times.

We'll see what happens in the AM after it cools down all the way.

Mystery not completely solved but....

IT LIVESSSS!!!!!! "que frankenstein lighting"

Cross our fingers for the AM. I expect the same result but... I won't take anything for granted after being shipwrecked for two weeks.

WOOF!

 

Mr. Eck
I assume you came to the forum to hear others opinions, so I will offer mine. You jumped to a conclusion about spark without valid data, and these cars are not known to normally succumb to "weak spark".

You have not actually replied to the implied question about chain tensioners. NO ONE with any knowledge of these cars would discount the need to change your secondary tensioners if they are not already done. NO ONE! Plenty of argument about the primary tensioners, but none about the secondaries from knowledgeable folks. Capiche?

You also previously stated you did not have water in the gas. How do you know? Frankly, your symptoms still point to that as a strong possibility.

My point is that these cars have a few quirks, and most problems can be attributed to just a few weak design issues. And diagnosing them by parts replacement can get expensive very quickly. It is much better to do data based troubleshooting and not jump to hunches which can lead you away from the actual problems.

I suspect your car will start fine in the morning and you have cleared this little disturbance. Good luck and keep us posted, that is how we all learn!

 

Mr. Ross

I agree with your claim on non-reply for the tensioner problem. I was unable to check the aforementioned tensioners because I was in fact out-doors. I felt strongly that the weather was not conducive to begin the dismantling process involved in checking for timing. Despite my personal inability to withstand working in zero to sub-zero temperatures. I think that would be something you and I would agree on.

To address your claims of properly testing my fuel system. I removed a sample of fuel from my fuel rail on two separate occasions. One which I talked about in my first post and a second time yesterday before using starter fluid. This being said the water could have been in the system post rail. I however, had many indications that I was receiving fuel. Which I also stated in previous posts about my plugs being wet.

I would also like to address your strong sentiments about ones opinions and my solicitation of them. You are correct I did arrive at this forum and solicit the opinion of the entire community. Which you've made the conscious decision to post. In no way am I required to pursue or invest in the said opinion of any specific individual. It is my responsibility to adjudicate an action based on the information that I have over a wide spread field of input. Of course that information is seldom perfect.

As to your claims of jumping to a conclusion. I believe that "weak spark" is at best interpretive and subjective. Without one actually seeing it in action, there is now way to properly come to a reliable conclusion.

To your implication about my "diagnosing them by parts replacement can get expensive very quickly"... Throughout this process the only thing that I have actually purchased was a compression tester and a $4 bottle of starter fluid. We can rule that out.

In conclusion, I have addressed this community with kindness and respect, and reading your last post I felt attacked. I apologize to anyone following along if this feels abrasive or brash but I felt the need to defend myself, and my instincts regarding this problem.

I am a new user and jumped in with both feet. If I have offended anyone by naïveté I do apologize, I am not experienced in proper protocols.

New news- The car fired and drove as it should first thing this morning; It has returned to its usual habit of having no reportable issues.

Mr. Ross, you are correct this is how we learn.

Thank you all for you help and opinions. Your support and analytical powers have been unquantifiable in resolving this issue. If any of you do not own a repair manual for this car I have a 3,000 page document (98-03 XJ8 *electrical included) in a zip folder that I will happily dropbox to you or email to you. P.M. me for arrangements.

Thanks,

Mitch Eckler

 

Mitch:
I am sorry that you feel "attacked". I did not mean to make you feel that way, but only to show my strong opinion about the process for troubleshooting and maintaining a modern high performance car, and to get your attention about the tensioners. Your problem could have very well been that, and it would have rendered you with a very bad opinion about Jaguars! I will try to be less obnoxious in the future. I certainly understand the lack of interest in freezing your *** off. Stuff like that is why I have several cars, so I can work on them when I feel good and ready.

You gave extremely detailed and valid information along the way that shows you are analytical and knowledgeable about mechanical stuff, but I will remind you that early on you made reference to "seeing about a new ignition module". You were also not so specific of what you had done and how you came to your conclusions. I have learned to not go with hunches if there is a way to actually diagnose what is wrong. In the end, you got it figured out without too much pain and $$. Congratulations!

BTW, one of the peculiarities of an X-308 is that the gas filler is located in a well, and depends on a small drain tube to discharge the water than flows in there. If that tube plugs up from leaves or other debris, water can get into the tank pretty easily if the filler cap seal is not perfect (the tank is under a small vacuum!)

 

Well, good news finally. So we are now assuming it was water in the gas: most likely. So that implies iced injectors or inadequate flow on the rails: wait, four plug sample were wet (?). obtw, nmbrd 1 - 4 right side, 5 - 8 left side. Wet plugs implied flooding or irregular enrichment (given it was so cold, I would suggest next time an eye dropper of oil down the plug holes will rule out bore wash quicker than a compression test. For all the time it took to change the plugs, you could have wrenched off a handfull of 5/16 nuts to check the tensioners.

-7*F was important data pt; so was fact it stalled (provided in a PM) so was (and still is) that it has plastic tensioners (provided in a PM).

Some lessons here: everything is important when troubleshooting; the value in the forum is the forum, lots of folks, some good, some less so, but helpful given the data; to a man, we think you are damn lucky the tensioners weren't the problem when the cranking and starter fluid started it up: as soon as it warms up, please CHANGE THE TENSIONERS, you are on borrowed time.

 

Thanks fellas. I'm sorry about my reaction.

Ross- Copy that on the filler cap. I'll be making sure that clicks from now on. Thanks for dealing with my craziness. Can I offer you a copy of the manual? Or pm me your address Ill send you a check, buy you a beer... I appreciate your help.

Jim- I promise I'll look at the tensioners. I think you are absolutely right about me being on borrowed time. The last thing I want is to be back in here again looking up info on a mill swap. I would like to help you as well. Buy you a beer or a manual copy?

On checking the tensioners... I'm removing the valve covers? I understand I can see the chains on top, along with the VVT solenoids, but from that point I can see the tensioners down below? I thought they did a factory recall on the timing tensioners from 01-03?

Info: I bought the car late march a year ago. It was living in south jersey. Single owner, and garaged. The cars condition is clean to very clean. I have no maintenance records other than what I can see.

As for what happened I agree, I think it was crap gas. I can't see any other way around that. If it ran on ether it couldn't be anything else. ...?

Now that its running. One of my rear calipers is a little frozen from being laid up so long but, I'll remedy that soon enough.

Thanks Fellas.

 

I hope it warms up soon.

You may well find metal tensioners when you open it up, but if plastic, replace. Buy the secondary kit from christophers in NJ, they will ship with the shorter bolts (or your local Lincoln dealer). You will see the tensioners as soon as you raise the cam cover (right side is easiest because you don't need to wrestle with the dip stick. Even if they look good, the blind side will likely have a crack (mine was 5/8'' right side 1/4" left side, looked brand new from the rear). Lots of good threads on replacing the secondaries. If the plastic "shoes" the chains run over are worn out, you will likely need to replace the primaries, too. Way more costly. When ready, either start a new thread for additional assistance or grab onto a later one. You will get more advice, mostly good, plus some interesting debates between the real pros (who tend to be purists) and the DIYers.

Calipers are easy. Lots of threads.

My next task is to replace front rotors -- just sure the 15mm and 17mm bolts are going to be completely ^^^^ing frozen!

Thanks for the offer for the manual, but I have it already: plus a couple of Gigs of stuff I pirated off this and Range Rover forums.

 

Mitch:
The secondary chain tensioners are much easier to replace than the primary tensioners since they can be done through the valve covers. Few, if any piston crash failures are reported due to primary tensioner failures, since they apparently put up a racket before the chains jump. So, although it is probably wise to do both, make sure to deal with the secondaries. Many years ago, a fellow challenged the forum to show a case of primary chain tensioner failure bending valves and got no takers.

I imagine i have the documents, and there is certainly no need for repayment since we all learn from others experience. As I mentioned earlier, these cars have a few significant design flaws and many common problems revolve around them. I believe you have a NA car, so besides the tensioners, the other main item you can do anything about proactively is the A drum in the tranny. Have a look at the archives.