I do most of my own maintenance and repair work, as the nearest dealer is 200 miles. I have replaced head gaskets, timing chains and tensioners, water pumps, etc., so I am confident I can do most things on the car. However, recently my wife's 98 XJ8 VDP has developed a problem. When attempting to start it the first time in the morning, it takes at least three tries to get it going. The first try the engine will crank and sometimes catch but not really run; it just "sputters". The second time. it will usually catch, but again "sputters". The third try. the engine will finally start, sputter just a second and then smooth out and run fine. Once the car has warmed up, it starts just fine first try. It will then start OK the rest of the day, but does the same thing next morning. I have changed the fuel filter, spark plugs (needed them), cleaned the throttle body, cleaned the mass air meter, replaced the air filter (needed it) and checked the fuel pressure (OK). I am concerned that it may leave her stranded sometime. Any ideas or suggestions, please???

 

Some of the control modules are very sensitive to low voltage. The starter will sound great, but no start.

It has been getting cooler lately.

So ...

1. check that the battery is in top notch condition
2. check and clean all major power feeds including the main cable run junctions, one you might miss is the high power module on the back of the trunk ... take out both fuses and clean all copper surfaces. Usual caution of removing battery cable first applies in spades on this one!
3. check and clean all major ground points ... especially the ground strap between the starter mount and body ... the attachment point at the body is not really great

All of the above is pretty much standard preparation for a trouble free winter anyways

 

If all that checks out that was mentioned above you may have the beginnings of cylinder was. I'm not saying that is exactly the problem but this is how it all started with my '98 VDP.

 

I checked all the above and everything checks out OK. It does not really feel like it is an electrical problem, as the starter works just fine. It feels more like a fuel problem or maybe computer, as the starter engages fine and the car tries to start but is "sputtering" or missing so badly that it will barely run. After the third try, the car starts up and runs normally, as it will do the rest of the day. This only seems to happen first thing in the morning. Any other ideas? Thanks.

 

If you installed new plugs, I'd be inclined to go back and check your install, sounds like a weak connection to 1 or more coils/plug boots.

What is OK in your mind for fuel pressure?

What's OK to you for a battery? anything under 12.5V will cast ghosts in the machine, 14V+ off the alternator.

Other than that, have you an OBDII reader, see what it says while doing it's 40-a-day start-up impression.

Have you done an oil change? what oil thickness? maybe time to go up a weight as it could even be loss of compression overnight with a thin oil.

 

ICW fuel pressure I would measure the fuel rail pressure first thing in the morning before attempting to start.

What is the pressure after overnight leak down ?

No need to try to start the engine, just turn the key on which will run the pump for 2-3 seconds. What is the pressure now?

Key on again, pressure?

Couple issues posted recently about pressure leaking down due to a failing back flow valve in the pump. Rev Sam went so far as to add an 8 second relay operated by the key fob door unlock to prime the system before the first start of the day.

 

First thing, if you were talked into platinum or split-fire spark plugs, get rid of them. You need the original type iridium spark plugs.

Beyond that, what you describe sounds like more than cylinder wash. I don't feel that would be as consistent as this. It sounds more like carboned up piston rings. See your friendly GM dealer and ask them for their product called top engine cleaner. It will come in a a bottle something like fuel stabilant, it has a measuring compartment on it. Get a length of rubber hose you can put a small funnel in and will fit into the spark plug holes. Put 1 1/2 ounces of the top engine cleaner in each cylinder and let it set overnight or a little longer. Then lay some heavy rags over the cam covers and crank the engine to expel and catch any liquid left in the cylinders. Put it together and go run the dog poo out of it for a few minutes. Then immediately, REPEAT, IMMEDIATELY change the oil and filter. Again take her for an aggressive drive and call it a day.

The piston rings can get coked with carbon and cause cold compression loss, that makes for hard starts, sputtering and stalling. But once it's running, it's usually good for the day. I've done this on several cars originally thought to be worn out. One of them got another 40,000 miles before hard starting showed up again.

It's a little work, but easy enough to do that it is easily worth a try.

Good luck!

 

Hl, If you used Bosch plugs that may be your problem. I recently did my 100,000 mile service on my 2006 XJ8 and puy new Bosch plugs in. About one month later I got in the car in the morning and just like yours, it occasionally sputtered but never started. End result was that the Bosch plugs have a problem apparently on the XJ and XK models. The local Bosch rep finally admitted that they do have a problem with their plugs on the two models quoted. After installing NGK plugs, all is well.

Peter 2006 XJ8 VDP

 

Peter,

Thanks for chiming in! I just can't repeat enough that sometimes that's all I do to repair a Jaguar, remove the Bosch Platinums. They get all the press, but they are not always the answer.

I feel a little vindicated by your real world experience.

Cheers,

 

I installed Bosch in my S-Type at 66,000mi and in my XK8 the second time at 110,000mi and to date no problems. I guess if it is a daily driver it makes a difference.

 

I would reccomend a cold compression test. When the engine is cold soaked, have a cold compression test done with the fuel delivery system disabled. If your compression is good, you can eliminate the gas wash and carboned rings as the only cause of your starting problem. It should be done after your car has been brought up to normal temp as you would normally do before you park it overnight. Then the next day, disable the fuel delivery system to prevent gas wash while you do the compression test.

This could take much of the guesswork out of your diagnosis. If the compression is low, add about a 1\2 teaspoon of oil to the cylinders and retest. If the compression readings are now much higher, you can confirm that you have an engine wear or the Nikasil syndrome or maybe even the carboned ring problem that was mentioned. I just found another thread with a similar subject. "
99 XJ8 Crank no start, wet plugs
John Fox

It's about 20 down from yours. "Gus" has a reply near the bottom that contains a link that very informative on the Nikasil and starting problems.

Please confirm my opinion with other more experienced Jag techs before you follow any advice I give.

Good luck,
Joe

 

Talk about coincidence........

One of our owners just showed up today, that had the treatment I spoke of in post #7. He had a no start/hard start/rough start in June of 2009; just like the OP tcbjaguarxjr talks about. We suggested we try the top engine cleaner business and to return in two weeks; if he saw improvement that we then wanted to put in new iridium spark plugs since he was at 100K miles.

Well, he didn't come back until today. Now it looks like we'll be doing a throttle body repair for TPS failure, an ABS Module solder repair for the C1095 fault, and those spark plugs. My writer asked about the starting and he's had no issues since the procedure. The car is at 111K miles now and is used semi-regularly all year, except when snow is on the ground.

Works for me!