I've got a 2003 XK convertible with 86,000 miles on it that has - what seems like - a fuel starvation issue. I just recently purchased the car, and previous to my ownership the car had sat almost entirely unused for almost three years. I first noticed the issue driving it back home, about 90 minutes after I bought it!

The symptoms are rough running, loss of power, and sometimes complete stalling of the engine... pretty much exactly like what you might experience after running a fuel tank completely dry. The car does this fairly reliably after about 40-90 minutes of driving, but sometimes it takes as long as 3 hours. When the issue occurs, it sometimes can be nursed along on very light throttle, but dipping into the throttle will cause the engine to stumble and oftentimes stall. Once the issue begins, it can often be impossible to drive the car: Every minute or so the engine will begin fumbling, and then quit. It will sometimes re-start and run perfectly, or sometimes not start at all, until a period of time (say about 4 minutes) has passed. Otherwise the engine pulls amazingly well - clean and smooth and all the power you'd expect. The next day, the car runs great... until the issue is back again.

Okay, well, seems like the fuel pump is a good place to start, right? Yes... took it to the dealer, they diagnosed a failing fuel pump, after testing the system hot and under load, and they found only 6psi in the fuel rails. They replaced the fuel pump and fuel filter. At the time I also replaced the spark plugs and the serpentine belt.

Except, after the repair, the same issue recurred after about 3 hours of highway driving.

Okay, a different dealer (at my final destination) diagnosed a fuel pressure sensor as the culprit (pulling codes P0191-P0193). In fact, the engine wouldn't start when I dropped it off (the first occurrence for that, after a mere 15 minute drive). Repairs: New fuel pressure sensor, fuel injection cleaning, and also replaced relays for the throttle control, and ignition coils (after finding faults for the throttle control).

Except after the repair, the issue recurred essentially identically to all of the earlier instances, after about 2 hours on the road.

Back to the first dealer, and they diagnose a failing fuel pressure sensor, again! I have it replaced (free).

And yet here I am, and the issue is still recurring time and time again, after roughly 40-90 minutes of driving. I can nurse the car back home on super light throttle, occasional stalls, check engine light coming on, etc.

My thoughts: the issue (whatever it is) seems to be somewhat 'heat related', in that an electrical component works for an amount of time, and then fails partly or completely. I am also wondering it it could be fuel contamination (some water in the tank?) or some blockage in the system, although I have no idea if that would cause codes to be thrown in the manner they are, and if the symptoms would only manifest after a period of driving...

I've searched through the forum and couldn't find a similar thread, so I'm hoping someone has some advice or thoughts. Thanks in advance!

 

Not sure what is going on but this might help you get closer to the problem. Go out and get yourself an OBDII code reader that you can plug into the car. Most will work find but you can find several recommendations on the forum. I have one that I leave in the car and it cost around $30.00. Plug the OBDII into the car and then drive the car until the problem comes up when it does copy what comes up on the dash like restricted performance, failsafe etc. At that time get to a safe place and read the codes that are on your OBDII reader and jot the codes down. A temporary or intermittent code will not set a hard code for the reader to see after the fact.

Post the codes and the info from the dash and we will try to help.

 

I assume you drained. Cleaned. Then refilled the tank?

May sound daft but hows your battery? You get the most weird symptoms when your battery is on its way out. Just google it and you will see what I mean.

 

Gus -- Good advice! I'll track one down and report on what I find. Thanks

 

frankc -- Hmmm... good thoughts. I didn't replace the fuel pump myself or fuel filter myself, so I can't speak to whether the tank was drained completely, but I doubt it... I can check with the mechanic and see what he says. Yeah, supposedly the battery is new, but it seems I should just replace it on principle at this point.

 

You should know if your car goes into restricted performance it will not allow the car to go over 2500/3000 RPM.

Gus
www.jagrepair.com

 

+1 on Gus' recommendation of an OBD reader.

What the dealer has replaced are all candidates for a car that has sat for 3 years, but you will empty your wallet at a scary rate if you're relying on him to keep the car in good health. I suggest you find a good local independent for the work you're not comfortable to tackle yourself. The good folks on here will likely be able to recommend one in your area.

 

Evan, You might want to have someone check the "Fuel Pump Driver Module"...It's in he Trunk up below the Fuel Tank....It tells the Pump when to pump and how much....It's made by VDO.....could be the problem! Of course you can't get a new one from Jaguar...….eBay...eBay...eBay!

Billy Clyde

 

Bill -- Thanks! I looked it up, and yes, that's just the sort of component that would escape the usual investigation. I'll order a new one this morning on ebay.

By the way, Grrrr... that is a nice looking XKR you've got there!

 

Evan,
Let me know how this works out for you....Was it the problem? Did it help? What do you think? eBay seems to be our new Jaguar Parts Store.....

Billy Clyde

 

As already suggested, get an OBDII reader, even a cheap ELM327 from eBay/Amazon. On the '03, fuel pressure is available over OBDII so you can read/record the pressure real time with an app like TorquePro. That pressure should be close to 55 psi at all times.

Separately, that ELM327 will help you read the OBDII codes. This problem could be as simple as a massive air leak from a cracked intake or from the many hoses on the heads. Codes will point you in the right direction.

Last, this ELM327 will also let you read the fuel trims, very helpful in chasing down air leaks, if any.

Have you tried any of the more reputable fuel system cleaners? Some swear by Techron. Make sure you follow directions, as more is not better (these products make rubber swell like crazy, do not overdo it).

Best of luck, keep us posted.

 

+1 on Techron. I had some fuel issues after my car had essentially 9 month old gas in it. A few tankfuls of Shell premium with Techron added smoothed things out a fair bit. A cheap thing worth trying (and probably worth doing anyway). You could have gelled fuel gumming up your filter or lines (or both). I'd be willing to bet your fuel is just garbage from sitting that long.

Potentially also worth inspecting and/or having the injectors refurbished. Ones that sit for a while can have their filters rust (I saw this happen when I got used injectors from an XJ8 to refurb and install into my 4.0). That's a third thing to try.

When fuel sits for that long, it breaks down, and additionally water can condense in the tank and further contaminate the gas. Obviously not your fault in this case, but I learned this the hard way last year.

 

Fmertz -- Wow, great insights there! I had no idea you can get real-time fuel pressure readings... amazing. I'll be able to grab a OBDII reader online today, so I'll keep you guys posted.

I've used some fuel cleaners in the past with my old MGB (it has over 300,000 miles on it by the way) and it solved some recurring issues that I thought at the time were ignition problems, so yeah - I'll find a good one and make sure I follow the instructions to the letter. I very much appreciate all of the support from the forum members. Thank you!

 

Also, to add onto the OBD reader suggestion (which I 100% agree with), if you want to shell out a little bit, you could get the Blue Driver bluetooth unit. You can use it to monitor real time readings (fuel trims, temp, etc. Really up to you), and it'll give you a freeze frame of what the readings are at the time a fault code is triggered. It's a bit pricey, but I got one and it's been somewhat useful with intermittent but persistent issues.

Edit: I missed fmertz's suggestion...oops! Either are worth a try (though admittedly if I had to do this over, I'd probably go with his suggestion over mine).

 

Another thing, check the cables to the battery. They sometimes fail internally and create major ground/supply issues. These cables should not be hot to the touch after a drive. Hot = resistance, not good. Also, check the ground strap between the chassis and the engine block. If you have poor ground, nothing electrical will work properly. Last, double check the supply cables to the various fuse blocks. Some have reported these cables being loose and causing random issues.

Another cheap thing is to clean/replace the air flow meter. They are pretty cheap for our cars (tons of cars use the same model). Look for a Denso 197-6030. 5 min to replace.

 

Sandwhich... The car was sitting in a garage in Oklahoma City (as far as I know). I suppose ambient humidity wouldn't make much difference to rusty injectors if the gasoline was contaminated with water, would it?

But yeah, the more I think about it, the more I wonder about the quality of the gas - and whatever else is in there - still floating around. Hmmm. Obviously water and other junk can sink to the bottom of the tank and get randomly stirred up, and yeah, I've had plenty of experience with old gas. Its just horrible. I've driven the car about 2,500 miles since it essentially sat unused for 3 years.... I'm gonna guess that's about 6 or 7 tanks of fuel. That'll help a bit, but other junk is going to need more drastic measures.

Anyway, okay... next fill-up it's Shell premium with Techron added! And the one after that, etc.

I've used a product called Sea Foam in the past to render any water in a gasoline tank 'inert' (forgive my chemistry misappropriation), which worked fine, but that was on an old carburetor-fed car with 8:1 compression, yadda yadda. I'll read up on it and see how that might work in this case.

 

You have to check in your particular area, but around here we have methanol in the gas for a good part of the year. My superficial understanding is that these "water in the tank" issues are mostly from the past. Methanol loves water, it's probably hard to keep water in there even if you wanted to. To a point of course. With 6 or 7 tanks, it is hard to see fuel quality as still a problem, though.

Is your check-engine light on?

 

fmertz -- I'm putting a new battery in the car tomorrow, so I'll have a good chance to check out the ground cables and so on... I've already poked around the fuse boxes (replaced the fuel pump fuse simply as a 'might as well' measure, even though it looked fine) and all of the boxes are in great shape, including the supply cables, thankfully.

Okay, a new airflow meter! Got it. Thanks!

PS -- I'm a little slow on the uptake, but I just figured out how your fmertz relates to your avatar. (smile)

 

fmertz -- Those gasoline fill-ups have included stops in OK, TX, NM, and CO... at big chain stations and at little places in dusty towns, so even if I tired, I couldn't tell you if methanol was in the fuel or not.

The check engine light is currently 'off', but the last big drive (60 minutes) it came on for the last 2 minutes. At that point it did the usual, staying on for the next few stop/start cycles, but then has stayed off.

 

Yeah, I agree. I didn't realize you'd been through so many tanks. If it was primarily a fuel thing, I'd think it'd be resolved by now.

Now that I think of it, if you had such low psi in your fuel lines, then the injector suggestion I made earlier doesn't really make sense.