Just checked with second auto parts store (NAPA) They said the Bosch plugs that I bought from the other joint are correct. Odd the length difference I noted above but I guess I'll go ahead and install all and hope for the best.

 

For the 2002's the owners manual "vehicle care" lists the plug:

NGK PFR5G-11E For both NA and SC engines.


I do not know if the earlier (First) V8 engine used a different plug --- so that could be a confusion if they do .........and someone is just looking at "Jaguar V8" -- but this is only a guess.

My memory is not clear when they went from AJ 26-27-28 and exactly when the steel sleaves started ..... not sure Jaguar knows


Do you have your owners manual?

 

Shorter would not be a problem. Did we ever find out what the noise was?

 

Just finished reinstalling, rechecking all the bank 2 plugs - have done nothing to bank one - and it was running fine yesterday after replacing two of the bank two plugs. Going to replace the coil cover, cross my fingers, say a prayer and turn the key.

 

Yes that is the one... I cleaned mine out with a drill bit also (not attached to a drill of course!)

 

Steve, from vin 853935 and up take iridium plugs, before that platinum.
now lets see if you have the noise. I cannot see that anything you did would cause a knocking issue.
Use a 3/32nd drill bit by hand, and by all meens be carfull disconnecting the tube since its plastic and very prone to breaking

 

Started it BRIEFLY.

Very rough - tap tap tap sound (probably four per second, very regular/rhythmic)

Shut it off immediately.

Next call is AAA to tow it in. Feel free to share your thoughts/condolences/sympathies.

Not looking good. Wishing I'd just left well enough alone after changing the first two plugs.

Brutal - my VIN doesn't look anything like the number you posted - mine ends in YLF06893

 

Steve that goes up into the F's for vin youre supposed to have Iridiums as spec'd from Jaguar. Certainly platinum shouldnt be an issue, but who knows, maybe we should consult jagular, he's proven me wrong before

 

'the old are overall about 1/8 inch longer. "

Where is the difference?

Is the difference from the hex portion to the connector tip?

If so, perhaps the coil is not able to seat correctly on the new shorter plug and you are hearing an arc between the plug and coil.

Say your engine idles at 700 rpm. Every cylinder fires once for each two revolutions. There are 60 seconds/minute. (edit: it did say once for each revolution - but nobody caught it )

Therefore,

750/2/60 = 6.25

Each cylinder fires approximately 6 times per second at 750 rpm.

If one is arcing you would hear about 6 arcs per second, and if 2 then 12 arcs per second, and so forth.

What are the brand and number of the old and new plugs? All of the manufacturers have application books that specifiy all of the important dimensions. It might also point out whether the old plugs are even the correct ones.

side note:

It does not apply here, but there was a remark earlier that differences in length do not matter. In fact it does. If the difference is in the thread length, it will expose either the plug thread or hole thread. Carbon buildup on either one can cause pre-ignition. If the difference is in the seat to firing tip, then a shorter dimension can cause fuel shrouding, and a longer dimension can cause mechanical interference. A difference as described above can cause bad connections. And then there is the matter of heat range which is mostly dependent on insulator dimensions.

 

Old are approx 1/8 inch longer form hex to tip of "firing end"

I can tell you the new are Bosch Platinum Plus 4002

Old were NGK but don't know the model # because they are with the car at the shop.

 

Steve, to rule out the plugs, especially the length difference, I would just take an old one up to NAPA or Autozone, and get identical ones, NGK irridium are very good plugs. Since the coils are a standard length when secured, it makes more sense that a shorter plug is going to cause a gap where plug/coil are supposed to mate. Losing $30 on four plugs is worse than the damage this could cause if ran under that scenario long.

 

Guys. Lets be clear. Noise started AFTER shorter plugs. I would like to hear the scenario that could cause shorter plugs making a noise immediately......

 

At this point the shorter/longer thing is moot. It's at the shop. Verdict expected Monday.

And remember - two of the new shorter plugs worked fine and smooth before I finished the bank. So I'm doubting size matters (in this case.)

Having said that, I still have no explanation for why, when it started it ran REALLY rough - probably would have stalled if I died shut it down immediately - and there was a distinct tap tap tap in the short time it was running.

 

I'm tuned in for the season finale

 

By all means, Steve, let us know the shop's verdict and we'll all pray for a simple solution!

 

We'll keep you posted.

 

the first thing to please do is to invest a small amount.......I moved to CO 5 months ago, my car ran fine for 2 weeks I have a 99 XJ with almost 200k miles...never a major problem.
I took it to so many places and they wanted anywhere from 1500 to 3000 to fix claiming it could lead to a catastrophe. mine was a no 2 cylinder misfire and I needed a new set of heads.
I've had my car since it was new and I know it like the back of my hand...I take care of her and she takes care of me.......I took it to a place and they did diagnostics which must have been one great computer system because they told me I had a bad spark plug boot. Normally you have to get an ignition coil to also get the boot but they found a place that sold just the boots. They changed all 8 of them, dyno'd the car and it's creating 362 hp at the rear wheels and it has never ran faster. Of course the performance chip helps.
keep us posted

 

Had a look at these side by side today:

Bosch 4002/FR8DPX+

NGK BKR6EGP

The stupid blister pack got in the way, but the Bosch does look longer in the gasket to nose dimension when measured through the blister pack.

speculation

If the piston contacts the ground electrode it would close the gap. Possibly shorting the plug. And, there may be residual noise from piston contact even after the initial contact.

Various application charts list the Bosch FR8DPX+ as suitable for the AJ27. But, the plug is physically longer. I like the Bosch, but maybe not in this engine. The center electrode is also completely covered by the insulator except for the tip surface unlike most plugs.

 

So the shop says the problem is two broken air intake hoses which makes no sense - I know I didn't even touch them (unless I bumped the one up top) If I understood him right he said there was one broken "underneath" as well - which of course I was nowhere near.

Can someone tell me with certainty where the air intake hoses are located? And I haven't been told yet the cost for the part or the time - so guesstimates along those lines would be appreciated as well.

What a friggin' adventure this has become - I guess the outcome could have been MUCH worse.

 

Okay - this seems fishy. Shop just called back - said to replace both breather hoses it was gonna cost $400 all in (roughly 80 for the parts and three hours labor)

He said they need to remove the manifold to get one of the hoses in place properly.

Bottom line - does that sound right?