I'm wondering how many others have encountered this on their XJ..... On warm starts, the car starts right up only to drop rpms, sputter and die. Seems to lend itself more often after a spirited drive or having done multiple errands. Let it sit for awhile and the car starts up like normal without issue. Heat seems to trigger the fault. Initially I thought maybe a fuel pump failure but now I'm not so sure..... The link to the thread below nearly describes my same exact scenario.....

https://www.jaguarforums.com/forum/x...-starts-52254/

Unfortunately, it was unclear whether they ever found the culprit. In my case, it does not always sputter and die on warm start-ups but it has progressively gotten more pronounced. It cranks and starts just like it should but then when the rpms go down, they go wayyyy down and it doesn't always recover. When it does, the car performs fine, no surges, no stalls, the idle is very stable and smooth which is why I don't feel like it's a fuel pump issue.

Also, whether this is related or not I've always have had a problem filling the tank past 3/4. Whenever I try the nozzle clicks off as if the tank is full when it's not. I've had this problem long before the warm start issue surfaced so I'm uncertain whether there's any connection there.

Any guidance/suggestions/feedback would be greatly APPRECIATED.

Tym
09 XJ Pearl Gray

 

If the fuel pump is good, it sounds like vapor lock. Try a different brand of premium gas.

 

I think it may be venting issue within the fuel system..... There's been mention of a "purge valve" that can make refueling a challenge. That still doesn't explain the hard starts when the engine is warm. I don't get a check engine light so there aren't any codes to refer to. Perhaps a clogged charcoal canister? I believe that would give similar symptoms.....

Any other suggestions?

 

Vapor lock does not give you a code. Purge and canister systems are NOT your problem.

 

Seems like vapor lock is prevalent with carbureted vehicles but not so much on fuel injected engines. From my understanding the V8 fitted in the XJ has a "returnless" fuel delivery system unlike many other FI engines. Would this make the XJ more susceptible to the vapor lock?

I've always filled up at Chevron exclusively for the past decade or so without issue. I will try another brand and see if there's any change in behavior.

What about the inability to easily fill the fuel tank past 3/4?

 

I was wondering dribbly injectors but I think then it would be tough to start at all.

Have a look with OBD at the temperature sensors (ECT, IAT) as it adjusts fuelling using them and needs them fairly accurate.

With a cold engine they should start near enough the same then ECT should rise past IAT.

The other thing you might watch with care is the open/closed loop status. Does it act up just as it tries to go CL? That's when it trusts a bunch more sensors etc. Something that's a bit off at the wrong time can cause grief.

 

My car has done the same thing a few times the past couple of weeks. I start the car a second time and it performs with no issue.

 

I've tried switching fuel vendors but noticed no change in behavior.....

I have noticed that if I prime the fuel pump(turn key to position 2 for a couple of seconds) before actually starting the car it does lessen the occurrence. In my case, when it does act up it will not always "catch" on the second re-start attempt. Revving the engine doesn't always help either......

I haven't had a chance to check temperature sensors as JagV8 suggested.....

 

I suspect a sensor going...maybe the common throttle body issues, (sensor on them goes bad) do some searching here, see if that's a common result.

 

are you getting misfires? it could also be what is basically the PCV valve on a jag engine.

 

No misfires.... Whatever it is it's definitely temperature sensitive.

I have noticed that when it does act up and I'm finally able to get it to start without it stalling the idle rpm's are lower than normal.

I feel like maybe it's the maf sensor?

 

Post #6 is cheap to try.

 

Sounds pretty much like the condition described in this bulletin.

Cheers,

 

Thank You! I think this is spot on with the issue I have.....

Looks like I'll need to make a trip to Santa Barbara soon(nearest dealer).

 

Mine's done this since I've owned it (five years this month), but only a few times a year. After it dies I start it and keep the RPMs high for about 30 seconds and it's good to drive. This topic was discussed in this forum a few years ago and one possible conclusion was the winter blend gasolines. I've noticed mine only does it this time of year, but it may be coincidence and all in my head.

If we take our cars to the dealer for this service bulletin are we charged or is it covered? I think I know the answer but had to ask - I'm part Irish and today's St. Patrick's Day so I'm feeling lucky.

 

Interesting. You realize why winter blend gas with ethanol causes this? It has a lower flashpoint that causes....wait for it...vapor lock.

I've run into this many times with many engines since they started adding the ethanol. It's always on hotter than normal spring days, when the gas companies miss-forecast the hotter temps.

Oh, one thing that can also exacerbate the fuel problem is if the check valve and/or regulator are not working right, so fuel pressure at the rail drops after the engine is shut down. These engines have no return line, so the vapor from boiled fuel has to purge through the injectors, resulting in false starts and rough idle until the bubble is purged completely.

A dirty fuel filter doesn't help either. Might be worth replacing it if it hasn't been changed in a few years.

Also, avoid 7/11 and no-name gas stations. If you can afford a jag you can afford decent gas...The car will thank you for it.

That's all I got...

 

If it's as per the TSB, that should fix it.

 

Did anyone get to the bottom of this problem, because I have a Jaguar XF that's started doing this same thing

 

Could be not enough high test gas sold, & water from condensation mixes in with the gas.

Try to use a station with a lot of traffic, indicating a possible quicker turnover time in high test fuel.

I've had good results with Costco's gas, place is almost always busy.

 

PrinceRandom,

The TSB about ethanol is for real in my opinion. I have experienced the exact symptoms you describe. I live in New England and it happened to me several times this past winter. 08 XJ8 would run fine and would always start right back up unless it was like a 5 to 10 min time period before I tried to start. 2 minutes no problem, 20 minutes no problem. And when it did do it the car will always restart and I could throttle it and it would eventually smooth out and run fine.

I found the TSB and was about to go to dealer and have reprogramming performed and Spring/Summer arrived (different fuel blend) and low and behold I have literally not had one instance of the problem in 5 months now. As in I did not have it done and the car has been fine. We had the hottest July on record here where I live and the car never sputtered once. (and she got warm a few times)

Because it is happening to you now, check the ethanol content from wherever you are purchasing fuel is my suggestion.