Hi. I apologize for multiple posts but I seem to not be posting in the correct area. I have a 1997 XJ6L with 106,000 miles. When I first got the car a year or so ago I was getting about 19 mpg. Now its dropped to 17. A couple of months ago I noticed the heater blower had developed a deep annoying noise which increases each time the car comes to a stop. When the car begins to move the noise would quiet down and the fan wouldn't blow as hard. Not much heat was coming out either. It was not a very cold winter and had not used the heater much. I have now developed other issues which may or may not be related. As I posted in several places(didn't realize I was an X300) I have recently been dealing with the car not starting and it actually stalled while I was driving. I had to let it sit a half a day before it would start. I then started it and moved it a couple of blocks. When I tried to start it at the end of the day......didnt start. Came back the next day and it started and have not had any problems since except 1 hesitation start but started on the next turn of the key. I don't want to turn my head and pretend that all is well. I did have the battery and alternator tested and both passed. Usually like clockwork right after it starts I will hear the fuel pump (not sure how to explain this noise) dip down and then come back up to the normal sound. At that same time the volts on the battery gauge drop. (If this is normal please don't laugh) I am far from being mechanically inclined and do not have any friends that are either. Sorry for the book, just wanted to get all the info so some wonderful person may be able to help me. I have fallen in love with this machine and feel so privileged I don't want to abuse it. I for sure do not have the budget for this luxury but any help on keeping it happy would be awesome! Thank you in advance!

 

Many possible causes. Might be as simple as a clogged air filter. Has the "check engine light" been coming on?

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A couple of months ago I noticed the heater blower had developed a deep annoying noise which increases each time the car comes to a stop. When the car begins to move the noise would quiet down and the fan wouldn't blow as hard.

Blower motor/blower fan noise is often something caught in the fan itself, or impending failure of the blower motor bearings.

Normal for the blower speed to increase a bit when the car is stationary then decrease when the car is moving. The blower is vehicle speed sensitive be design. Mine does the same thing (so are the wipers but the difference is very subtle)

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Not much heat was coming out either. It was not a very cold winter and had not used the heater much.

To clarify, the air wasn't very warm or the volumn of heated air was low, or both? If the former, it's often just an engine thermostat causing the problem----the engine coolant doesn't get hot enough to heat the air. Is your dashboard temp gauge reading on the low side of teh scale? If so, there's your sign.

I might add that the engine running too cold is one possible casue of your drop in fuel economy.

If the volume of output thru the vents is low it might be related to a faulty blower motor...the one that is making noise. If a blower motor is starting to seize from a faulty bearing or such, it won't provide much air flow and will be noisy.

The climate control has a self diagnostic mode that will display faults codes on the little screen. You have to push the right combination of buttons to enter this mode. I can't remember what the right combination of buttons is but someone will come along and let us know.

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I have now developed other issues which may or may not be related. As I posted in several places(didn't realize I was an X300) I have recently been dealing with the car not starting and it actually stalled while I was driving. I had to let it sit a half a day before it would start. I then started it and moved it a couple of blocks. When I tried to start it at the end of the day......didnt start. Came back the next day and it started and have not had any problems since except 1 hesitation start but started on the next turn of the key. I don't want to turn my head and pretend that all is well.

You also mentioned previously that the fuel pump was getting loud.

Previous advice was that the fuel pump itself and/or the crank position sensor might be to blame. Both good guesses, both common culprits. The only way to know for sure is to test them in failure mode. Lacking that, if you wanna take a stab at something, go with the crankshaft sensor.....less money to replace.

However, to clarify, when you say it won't start do you mean the engine cranks over but won't actually start....or do you mean it doesn't even crank over.....likea dead battery?

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I did have the battery and alternator tested and both passed. Usually like clockwork right after it starts I will hear the fuel pump (not sure how to explain this noise) dip down and then come back up to the normal sound. At that same time the volts on the battery gauge drop. (If this is normal please don't laugh)

Not sure what you're hearing; not sure if it's the fuel pump but, then again, you've mentioned a loud fuel pump before. The volt gauge won't typically drop and bounce back as you've described.

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I am far from being mechanically inclined and do not have any friends that are either. Sorry for the book, just wanted to get all the info so some wonderful person may be able to help me. I have fallen in love with this machine and feel so privileged I don't want to abuse it. I for sure do not have the budget for this luxury but any help on keeping it happy would be awesome! Thank you in advance!

A qualified mechanic....preferably one experienced with jags....will be able to help.

Cheers
DD

 

Hi Doug,
Thanks for such an informative response.

'Might be as simple as a clogged air filter. Has the "check engine light" been coming on?'
No but the transmission light came on when it stalled last week. It went off shortly after.


To clarify, the air wasn't very warm or the volumn of heated air was low, or both?
I want to say both not much volume and very little heat.

However, to clarify, when you say it won't start do you mean the engine cranks over but won't actually start....or do you mean it doesn't even crank over.....likea dead battery?
It turns over just fine, just over and over and over. Got stranded again tonight. After no problems driving every day 40-60 miles per day since Saturday. Very frustrating! I have been watching the battery gauge when I start the car and typically it will be about a 1/4 of the way maybe a tad over 9, but tonight it was way up at 14. I thought this to be odd Not sure if this helps. I will wait to see if any one else wants to chime in on this. Either way I will most likely have to take it to the shop. What is involved with replacing the crankshaft sensor? Is that something I could do myself?
Thanks again.

 

By the way the air filter is new.

 

Yes you can! Very easy, see post #51 here:

https://www.jaguarforums.com/forum/x...s-66536/page3/

I was fitting Andy's improved performance bracket, but the process is the same. You can see how the sensor comes out, probably can just replace the sensor without even pulling the bracket off since you are not changing that bit. It probably depends how much "gunk" is on your sensor.

 

Well had the car at Jaguar shop all day with no luck, of coarse it would not duplicate the "no start" issue. I have been thinking... As you can see by the photo that at home I park on a slight hill. I have never had it not start at home. The two places it has not started are flat. I know this is a long shot but the only two things in common are that and the fact it starts fine when it is cold. Its usually after it has been driving and then sits for a while. Could it be something like a thermostat or sensor?

 

As for the crank sensor That is a bit expensive (200.00) to be guessing so I decided against replacing this just yet

 

Weird things can happen but IMHO I wouldn't make too much of the slanted versus flat parking






Thermostat, no.

Sensor, yes, possibly. Or a faulty relay, or loose wire, or corroded electrical connection....or....or.....

In a situation like this you'll either have to spend some money on guesswork replacements or hope the symptom becomes worse (in your case, more frequent) so that your mechanic has a better chance of identifying the fault.

Or....pay him his hourly rate to do some intensive examination and exploring....which still may or may not reveal the exact cause of the problem when the symptom is absent.



Good luck
Doug

 

Today was the second time that it stalled while driving. I was able to get it to Jaguar in time for the issue to be diagnosed! Im happy to report it was not the fuel pump! They have determined it is the crank position sensor. Thank you to all that helped with suggestions.
I will be back with some cosmetic questions once I get back on the road.

Thanks!