Hi, I have an annoying issue. After running errands on a fairly nice day, my 2004 XJ8 started sputtering after it had been sitting for about 20-30 minutes. Start up car, engine starts sputtering, give it gas and drive and it goes away. Eventually, check engine light came on and codes were P0300, P0301, P0303, P0305 and P1316, which I was told was various misfires. Jaguar dealership recommended three part fuel system cleaning procedure and I scheduled it for the next day. Went to start the car the next morning and car would crank, but not fire until finally on the fourth or fifth try. Drove it an hour to the dealer and had the procedure done. On the way home, I stopped at a store to do some shopping, came out 20 minutes later, started car and sputtering returned. No check engine light came on this time and I have not seen it return yet. A few days later though, the crank/no fire problem returned. Following the advice of the posters here, I have been able to get it started using the hold the gas pedal down, release about a quarter of the way and the car will eventually start, albeit with a cloud of smoke from the exhaust. Brought it back to Jaguar and they mentioned that there was a code concerning the fuel pump and the service manager believes replacing it would solve the problem. I don't have a problem getting it fixed, but I'm trying to figure out if it really is the fuel pump. He didn't sound very confident in the diagnosis and I'd hate to throw away $1200.00 only to see the problem return. My question is that if it really was the fuel pump, wouldn't I be seeing constant issues? I can start the car on the first try about 2/3's of the time, but there's that one time where it wont kick over. I believe he said that there was pressure on the rails, which also makes me wonder about the pump. The times I've had trouble firing it up is after it's been sitting all night. Once I get it started, I can start it later that day with no problems, and sometimes it will work for two days straight. I've resorted to starting the car late at night and letting it warm up with a short drive in hopes that it will start in the morning. This worked Monday and Tuesday mornings, but this morning it did not. Any insights?

 

Multiple misfires on four cylinders, and diagnosed to fuel system cleaning and now a fuel pump? What do you know, all on the same bank too! I'd be looking at that passenger bank more carefully before going fuel pump crazy. Could be coils...electrical harness on that side, maybe even an O2 sensor. There are easy diagnostic procedures that can eliminate any and all of them one at a time before dropping $$ on parts replacement. May I suggest a second opinion, perhaps a good, independent mechanic with jaguar experience?

 

Last time I had random misfires it was a tank of bad gas. A little water in the gas wrecks havock with the diagnostics!

 

Thanks guys - appreciate the feedback.

H20boy - the Jaguar service manager mentioned something about that when the car sits, the fuel in the system starts draining back to the fuel tank and when you try to start it later, a failing pump may not push the gas forward as well. Also, the guy that pulled the codes originally was an independent guy and he wanted to replace all 8 ignition coils with used ones ($98.00 ea), and replace all 8 plugs ($14.35 ea) for a total, with labor, of...surprise! $1200.00 (what do these guys do - confer with each other!) My dad has a guy that he swears by so I'm going to bring it over to him and see what he says.

cjd - I thought that may be the case as well. When I picked up the car it was pretty much on empty so I filled it up at a Phillips 66 and drove home with no issues. The next day is when everything started happening. The previous owner swears he never had any issues with the car, but of course, what else is he going to say? That being said, I have filled up the tank three times since then, had the 3 step fuel system cleaning, and also put in a bottle of Chevron Techron fuel system cleaner as well. Would bad gas still be affecting it after all that?

Had a little bit of trouble this morning as well, but started on the second try. I guess my late evening drives aren't really helping.

 

Doubtful it's bad gas after 3 tanks.

The fuel rail on this car is not supposed to lose pressure. If it does leak down you will get a vapor lock in the rail. This is easy to check, as there is a pressure fitting to check the pressure on the left side of the engine under the plastic cover. Unlike other engines, there is no fuel return to the tank. A vapor lock has to be purged through the injectors.

 

agree

I see it all the time. Is the fuel pump check valve, which is integral to the fuel pump. The fuel is draining down back to the tank because the check valve is supposed to keep fuel at the rail. You still see "pressure" because the pump works, and is pumping air, but if you press the release on the pressure tester you will see air comng out for a bit, and since the system doesn;t have a return line it has to pump air through the injectors. Tell your mechanic to test for fuel pressure and hold the release on the tool, he will see air for a bit and then fuel. Then he will sound more confident and you'll feel better.

Let us know!!

 

I will daxter - Thanks!

 

A few more questions.....any tips to get it started when this happens besides what I'm doing now? How long can I wait to get this fixed? I just purchased an extended warranty, which would cover this, but they have a 30 day, 1000 mile waiting period.

 

If you still can, I would return the extended warranty. I have about 20 customers that bought it and are not happy with it. They will repair anything that doesn't break...

To my knowledge there is no easy way you just have to keep cranking it until it goes... Anybody knows a trick?

 

The only trick is to turn the key to "on", pause for a 3 count and then crank. That just gives the pump a chance to compress the vapor lock so it will purge faster. If no start after about 5 seconds of cranking, turn the key to off and repeat till it does start. Don't wait more than a 3 count, as the pump turns off as a safety feature if the engine doesn't start.

 

Thanks guys - I will give it a try.

dax - I can cancel at anytime and get a refund (pro-rated after a certain amount of time) so I guess I will give it a try for awhile and see if I have any issues when/if something else goes wrong. It's through Carchex, which seems to be rated as one of the best.

 

Fuel injection systems don't vapor lock.

 

Not if they are operating properly. Reread the posts above and you will see the tech believes the pressure is dropping on Darkman's rail. The boiling point of any liquid is related to pressure. In a good system you are correct, the fuel will not get hot enough to boil at 60psi. If the pressure drops when the pump is shut off, it most certainly can boil when the pressure drops to nothing.

 

Sorry for no updates, but I finally had the XJ8 towed to Patrick Jaguar of Naperville on Saturday and apparently it has stumped them as well. Had a helluva time starting it up Saturday morning and it wouldn't turn over. Finally gave up and called a tow truck to bring it over to the dealer. Waited about two hours for the tow truck to show up and decided to try it one more time before he hooked it and of course it fired right up. Had him bring it to the dealer anyway and when they went out to try it yesterday morning, it started and showed good pressure on the rails (50 psi). They tried it again this morning and it wouldn't start easily, but I guess they did get it started eventually, but again, they couldn't find any issues because it started up. They are keeping it again overnight tonight and have supposedly "hooked it all up" so they can see what it does when it doesn't turn over tomorrow after sitting overnight. I tried telling them what was suggested by cjd and daxter, but I don't think they like hearing opinions from message boards, no matter the level of experience (just my opinion) Anyone have any ideas of what I should offer up, or how I should present it, to them if they cant find anything tomorrow? Supposedly they are seeing engine misfire codes and one about the fuel pump (hello?) but again, he didn't sound too confident about a diagnosis yet. I'm starting to get a bit peeved, as I just want to enjoy this car!

 

Here's the latest. Fuel pressure before start is fine, 35 psi, and during crank, pressure jumps up to 60 psi so they believe it is not a fuel pump issue. There were several misfire codes, but the jaguar dealer does not seem to think it's coils or plugs. He wants to try a crank sensor from a known working car and try that. Frustrating part is that they have to leave it sitting for 8 hours each time to simulate the issue. Does this sound like a valid plan of action or should they be looking elsewhere?

 

They changed out the crank sensor and no change. Apparently they are now waiting on a call back from the national Jaguar hotline or something. They are stumped.

 

May be a bad ECM.

 

Tomorrow will be a week since it's been at the dealer.....no contact from them today at all.

 

The Thomas J, you may be onto something, but I thought the ecm was up front? Finally got a call from the dealer today and they seem to think that the electronic control module (?) in the trunk got wet and is the likely culprit for this issue. They said its a $900.00 part and an 8 hour job for a total of ~ $2200.00. I asked them to look for a used part and I'd get back to them. Does this sound kosher to you guys? I just want my car back so I don't really care about the cost, but I want to make sure that this will solve the issue and they're just not guessing at something to get me out of the shop. Any input would be welcome.

 

Sounds highly suspicious to me!

AFIK there are no modules in the boot (trunk) which are involved with engine management.

The ECM is under the dash and 8 hours to plug a module in!!

If it was my car I would take it off them ASAP.