I was driving onto I-15 when about a quarter mile onto the freeway, I started losing power. I knew something bad was going on so I pulled off the freeway onto the shoulder. The battery light went on right when I started losing power. After turning it off (or the engine turning itself off), I could not re-start it. It was definitly trying to start so I don't think it was the battery. The tow truck guy put gas into it and it still didn't start. I never thought it was out of gas anyhow.

I recently-

Replaced the transmission fluid
Replaced the coolent
Replaced the spark plugs and spark plug wires
Did a fuel system cleaning

It ran fine after all of these things were done.

Any ideas?

 

Sorry to hear that, Steve. What a bummer. Alternator and battery is the first thing that comes to mind, but I shouldn't think that the battery would have enough juice to turn the engine if it had been drained down by a spent alternator. Do you have any fault codes on the VCM?
Scott

 

Hi Scott. My friend who's a car geek said alternator too. That was without looking at it of course. I could live with it being the alternator because at least that is simple and not some specialized "Jaguar problem".

 

Sorry to heat that . I suppose there is a fuel pressure problem with your car from my hayseed opinion

 

Sounds like a fuel problem to me but I would check to see if the plugs have a nice Blue spark before starting on fuel system diagnostics.

 

Hi Steve,

See my thread, Roadside repairs for a check of the simple things. An excerpt from Haynes may be found there.

If you don't have a Haynes, get one and read it. It is an indispensable tool for troubleshooting.



You didn't jar an electrical plug/connector somewhere while doing maintenance, did you? Please explain "fuel system cleaning"?

1. The first thing I would do is check the condition of your battery. At least take it to an auto parts store like Advance and have them run diagnostics on it. A battery can be good enough to crank an engine, but not have enough voltage (due to high internal resistance) to run the XJ40's sophisticated Engine Management System (which is voltage sensitive).

2. Check the condition (both ends) of the battery wires and connections.

3. Having done that and still NO START, you've got to determine if it's a "fuel" or "fire" problem. I strongly advise you not to just throw money at your car because you think it may be this or that. Following that philosophy is expensive and frustrating.The results of these simple tests will determine what you should do next, ob.

WARNING: Excessive cranking of the starter motor can overheat it and cause serious damage. Never operate the starter motor for more than 15 seconds at a time without pausing to allow it to cool for at least two minutes. - Haynes

 

Guess what-The Auto Service place said it was some of the ignition wires coming loose. They re-attached them and were able to start the Jag and drove it around their lot. The last time any maintenece was done on it was 2-3 weeks ago. It drove fine since then until Tuesday. I don't know what made the wires come loose. I also didn't know "ignition wires" are the same as "spark plug wires". The Auto Service place ordered new spark plug wires. The spark plug wires that came loose were ordered by a Kragen Auto parts employee and are only 3 weeks old. They were installed at a Valvoline. I wonder if the Valvoline guy screwed up. The new spark plugs were also supplied and intalled by a Valvoline place.

Any thoughts on replacing the spark plugs? In other words, should I trust the ones Valvoline put in there? I don't see why the spark plug wires need to be replaced if it was a Kragen Auto Parts place that matched them to the Jag.

 

I like to use good quality (not Champion) Platinum plus spark plugs in my cars. In my Velomobile Lithium Polymer Cobalt gives it the fire of desire to get down the street.

 

Steve,

Yes, Haynes' "Roadside Repairs" does say to check all connections, does it not?

To me, ignition wires mean something else. The Brits call spark plug wires, HT leads. Who knows?

The Kragen Auto Parts' spark plug wires should be under warranty. If they are only 3 weeks old and if they fit your plugs, loosely, tell them you want a free replacement or you're gonna take your business elsewhere.

Check your wires to see if they are loose now. They should be snug and tight. When fully seated they should even click.

In the past, I've had wires so tight I now smear a little dielectric grease around the inside of the sparking plug boot on new wires. Why? Because when it comes time to replace the plugs, you don't want to break the wire when pulling it off, now do you? Then you'll have to buy a new set of wires.

I think the Valvoline guy forgot or just didn't push the HT leads fully on.

I would remove one spark plug and check to see:

1. if it's the correct plug for your car,
2. if the gap has been set correctly and
3. if they put anti-seize on the threads. If they didn't put anti-seize on the threads I would strongly suggest you pull them all and do so.

Steel and aluminium threads don't mix with water and will corrode and rust weld together. If this happens, you'll wind up destroying the threads in the head when removing the plug and a hel-coil will have to be installed to restore the thread. This is not cheaply and easily accomplished. It's better to put the anti-seize on now.

You're learning about the high cost of unskilled labor.

Glad to read you're on the road again ... and not behind a tow truck.