Hi All,

I just tackle a spark plug replacement last night took me about 2.5hrs. I also replaced the coolant reservoir as the sensor was going bad. Taking out the reservoir to tackle this job I think is key getting out the spark plug in cyclinder 5 was definitely a challenge even without it in the way.

Anyway, i just wanted to ask about the condition of my spark plugs. I believe they look pretty normal from the research and videos I've seen. I think my fuel mixer maybe rich, but I'm just speclating.


hi

 

Nothing unusual and they look good. Did you use the correct factory replacement plugs?
Factory says 100K miles and your at 117K miles so not bad on mileage either.
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Yea, I definitely pushed it a little bit, I was starting to get a bit of a rough idle. That with the coolant tank pushed me over the edge to do it. Those plugs were sitting my garage for over a year funny enough. but other than that the replacement were NGK Iridium plugs I got off rockauto.

Any concern about the discoloration around the white part the coil would sit on ?

 

What if you do not use the OEM plugs? I did not use the factory replacement plugs I used DENSO 4712 Iridium TT; Pre-Set Gap: 0.040" Info from from Rockauto
Could this be the reason my engine has knocking noise ?

 

You mean the ceramic insulator?

 

Rust on the porcelain is normal.
I use factory plugs unless there is a reason not to? Jaguar made the car and specified the plugs.
Will others work? Maybe but I don't need to find out because I used the right plugs.
I try to eliminate problems not create more.

Why did you change from factory?
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These looks normal for me too.
Some ignition coils are very sensitive for the sparkplugs. Newer understand why so, but good exsample is certain year of Fiat Punto. Add Bosh, NGK or Motorgraft with same temp value than original Denso. Misfiring and rough idle. Insert original Densos and running smooth again.
Back "old" days of distributors, you got spark or you did not get a spark.

 

All the computer chips make the cars picky and high maintenance

 

Vasara know this if you want to talk about picky? The old stuff (Distributors) were WAY worse! Don't even think about points.
Give me a nice digitally controlled ignition system with individual coil on plug setup over that old crap anytime!
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Those plugs look very good to me with almost zero electrode wear and no sign of damage, running lean, running hot, running rich, wetness etc.
The slightly darkened tips are undoubtedly due to a small amount of carbon build-up, mostly on one plug out of six - the top plug in the first pic - and not caused by running rich.
The factory spec NGKs are at least as good as if not better than any other plug you could find and there is zero good reason to change from them.

 

You are absolutely right on this. Modern ignition systems are far less problematic and last miles than nothing back then. I remember too well the innoying adjustment of points. (donīt even want to think about manual valve clearance check in every service)
Only nowdays some electronic ignition coil modules are very sensitive for what spark plug is inserted, when old systems did not care at all.