Hi I am new to the entire Jaguar experience. I just bought a 1999 Jag XJ8 4.0 V8. Ran Fine for 800 miles. I go to pick up my girl and I get within 2 miles of her house and it quits. It turns over but wont start. I left it sit over night and I returned to it started. I drove it 4 miles home and parked in my garage and it did the same thing. I took the air intake tube off and poured just a small amount of gas in throttle body. It fired right up then stalled when it used all gas. I let it sit for 1 hour it starts and runs...I drove around block and back to garage. Turned off engine and no start....I can keep doing this vicious cycle...where do I start ????? Any help is appreciated in advance. 1999 Jaguar XJ8 4.0 V8.

 

Problem is in the fuel system. 1. Fuel pump 2. clogged fuel filter

 

any tips on further diagnoses?

 

Do you know the service history of this vehicle and if the primary and secondary timing chains, guides, rails and tensioners have been replaced with the latest versions?

 

if its the fuel pump...someone told me it has 2....is that correct?

 

The XJ8 has one (1) in the fuel tank. The XJR has two.

 

I'm not sure about 2 pumps in an XJ8 but the XJR has 2 so maybe. The quick way to know for sure is to pull the lid on the trunk mounted fuse/ relay box and check for 2 relays.
I replaced both pumps in my recently acquired XJR and am sure one was bad. I also had similar symptoms to yours before replacing them when I pulled a jumper wire someone had installed to connect the grounds on both fuel pump relays to a chassis ground.
I found this the first night the car was in my driveway and pulled it but after that the old girl wouldn't start. I'd crank and it might get close to catching but would stall immediately.
I put the jumper back and she ran. I wouldn't recommend duplicating the jumper but I think the fuse box connections are a little weak. I ended up flashing a thin coating of solder on each of the 5 relay lugs and then plugged them back in without the jumper. It looks as if that solved my issues, after replacing the pumps and everything is running fine (no more restricted performance messages).
I plan on doing this to any suspicious relay I run into in the future prior to throwing any parts at the Jag. It's pretty easy to do although it would be a good idea not to get the relay too hot while coating the terminals. Flaky electrical connections are bears to chase down (IMHO).

 

My 1998 XJ8 Landen Plas w/the 4.0 V8 did the exact same thing about a month ago. I was driving down the highway and the vehicle simply lost power, shut off. I coasted to a stop, waited a few moments, and it restarted. It did the same thing about four more times on the way home. (about 30 more miles to home.) I bought the fuel filter for $12.00 (US) and went to task in trying to find the the fuel filter, which was quite the adventure in itself. You may already know where it is, or may have already changed it before. I'll post a few pics for those that don't know, or haven't changed theirs before.

My 1998 XJ8, Drivers side. You will be using the jack and will be removing the left rear wheel. Be sure to make the car safe to work under, ie: Jack Stands, etc.



With the wheel removed:



If you'll look to the right, (towards the rear of the vehicle), and up, above the Half-shaft, you'll see the filter wrapped in a brace.



A better view:

Another quick note: The fuel filter has "IN" and "OUT" sides to it. My replacement wasn't stamped on the ends like the old one shown in the pic. It was stamped on the side of the filter with an ink. And if the leaked gas gets on that stamp, it will run and disappear on you. Just compare the new filter ends to the old filter if that happens and mount it correctly.



This is a pic of the filter and the brace. Once the fuel lines are loosened and removed from the fuel filter and any spilled fuel is contained, loosen the center bolt of the fuel filter brace. If the filter is stuck to the "vibration dampening" foam rubber, it may be needed to remove the bolt. That wasn't the case for me. Mine was free after loosening the center bolt and the fuel filter slid right out of the brace easily. (See pic pointing at center bolt) Removing the entire brace is not needed. The "vibration dampening" foam rubber is attached to the brace, not the filter. The filter will slide right out.



Don't forget that there may be a lot of fuel pressure still in the line, depending on how long it's been since you've turned on the ignition key, or driven the car. Have lots of rags around to contain the fuel that's lost. There has been discussion about using a valve in the engine compartment to relieve the pressure, if that's the route you want to take.

As a side note, the filter is a Fram Fuel Filter #G3727, available at Walmart and any other reputable auto parts store, since it fits many, many models of GM cars and trucks. About $12.00 (US)

I haven't taken pics of the gas that came out of my filter. I could not blow through the filter, at all. The gas was dark brown with lots of silt and debris. I took a 12 oz. clear plastic water bottle and slipped it over the line coming from the fuel tank and had a 2nd person turn the ignition key on and pump fuel into the bottle, which I was very glad that I did. I was amazed at how much debris came on out of the line that was backed up behind a very plugged fuel filter. At least I will start with a clean line now. I'll try to take pics of both of those bottles, since I saved them, and post those, as well.

One other note. When the car lost power those times, I got a couple of error messages. I know the lack of fuel caused it, but I'll give you the codes for future reference.

Code: P0308
Code Definition: Cylinder 8 Misfire Detected

Code: P1316
Code Definition: No code definition available. (at Oreilly's Auto Parts code tester)

I hope some or any of this helps. I'm sure I made some mistakes in the correct terminology, but the results were successful. It sure made a difference in my XJ8's all-around performance.

firstchoice

 

firstchoice,

Thanks for the phototutorial!

BTW, it's easy to relieve the pressure in the fuel system:

1. Remove the gas filler cap to relieve any pressure or vacuum in the tank;

2. Remove the fuel pump relay(s);

3. Start the engine and let it run until it dies. The fuel system is now depressurized. If the engine won't start, the fuel pressure regulator (FPR) and/or fuel check valve are probably no longer holding pressure.

Don't forget to reinstall the fuel pump relay(s) after you've changed the filter.

Even with the system depressurized, there will still be a little fuel loss when you disconnect the pipes from the fuel filter, so your tip about having some old rags at hand still applies.

Cheers,

Don

 

Thanks Don B!

Myself, when I'm trying to find help on a particular repair, phototutorials are a great help. (to me, anyway.)

Those are great suggestions for releasing fuel pressure. I hadn't thought about the simple removal of the Gas Cap. This is why I like to read and participate on this forum. Lots of combined experience and experiences shared. Thanks!

firstchoice