A couple of weeks ago, my 2004 XJ8 failed to start for the first time. The engine turned over fine, but would not fire up.

Then it happened again a couple of days ago.

The only common condition between the two occurrences was the extreme heat outside (96+) sitting for four hours in the sun.

Both times, I waited, then after pressing the accelerator multiple times, the car fired up. No problems at all after the car started.

I haven't had to press the accelerator on a car at startup since the carburetor days, so I thought that was a strange thing to have to do.

The problem seems to be fuel starvation in extreme heat.

If that be the case, where should I start looking?

 

Interesting. When I bought my x308 several years ago, I discovered that it would not start either after sitting out in the hot summer sun. But mine would not do anything, like the electrical system was totally dead. It took a couple of turns of the key before it would come to life and turn over. I found the work-around was simple enough. Now I make sure to always put a foil shade in the windshield, leave the sunroof tilted and four windows cracked about an inch. Its been several years now and never failed to start on the first try as long as I follow that procedure. My theory is that some critical component, perhaps in the instrument cluster module, would get hot enough to malfunction in the Texas sun.

I'll be interested to read if you find the cause.

 

My '04 XJ8 is still failing to start about once or twice a week.

Here is the sequence of events today:

Started my car a couple of times this morning to drive short distances.

After the second time, I noticed a strong gasoline smell outside of the car.

Tried to start a third time, the starter turned over but the car would not fire up after a few tries.

At this point, I am not sure if it is flooding (because of the brief fuel smell) or starving for fuel. I read somewhere in this forum that if flooding is the issue you start with the gas pedal fully pressed closing off the fuel supply followed by gradually releasing the pedal. I tried that this morning with no success. Next I tried pumping the gas pedal while starting. That seemed to work in the past. No success there either.

So I left the car alone and worked on some other Saturday projects. After about 20 minutes or so I tried to start again. This time it started right away, stuttered a few seconds, then ran fine the rest of the day.

I'm sure the car will run fine now for the next 4 or 5 days or so. That is what is so frustrating.

Before I take my XJ to my independent mechanic and start the per-hour clock ticking, I thought I ask you folks if you had some ideas.

Many thanks,
Wayne

 

Hi Wayne,

There are probably several potential causes, but at this point we can only guess. I think it is likely that the kind of failure-to-start you are experiencing might trigger one or more Diagnostic Trouble Codes (DTCs), which are stored in the memory of one or more of the car's electronic control units (ECUs).

So my first suggestion would be to have the car scanned for codes. Most auto parts stores will scan the car for free, but their OBDII/CAN scanners can only read the P (Powertrain) codes. Those alone may be helpful, but it's possible you also have B (Body), C (Chassis) or U (Undefined, mostly network-related) codes. To read those requires a Jaguar dealer-level diagnistic system, or a high-end third-party system such as AutoEnginuity with the Jaguar extension. There are some DIY options, but before you go to the expense and trouble, have the car scanned by your local auto parts store to see if there are any P codes that may be helpful, and we can go from there.

And two more question I can think of:

1. How long has it been since your last tune-up? Fuel fiilter, air filter, spark plugs, MAFS cleaned?

2. Have you had any indication of low battery voltage or poor battery charging? If the battery voltage falls too low while cranking the engine, the Engine Control Module (ECM) will not trigger the ignition to fire (which could explain the unburned fuel you smelled).

Please keep us informed.

Cheers,

Don

 

Thank you, Don, for your thorough response. I'm overdue for filter and spark plug changes, so that's where I'll begin. The battery seems ok, but I'll have it checked anyway.

Thanks,
Wayne

 

I would also swap out the fuel filter. Its an easy job to do.

https://www.jaguarforums.com/forum/x...ge-how-119351/

 

Sorry, for the delay in following up with the solution to this issue. My independent mechanic replaced the fuel pump. I have had no starting issues since.