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What can be read from the magic black streak? Context - low miles, ran a couple times a year the past decade, I replaced the air filter about 2 months ago along with a bunch of other low hanging fruit maintenance things (before tackling the big maintenance jobs...). Ran her really hard the last couple of days before shutting down for the big repairs about 4 weeks ago.
1989 XJS Convertible air filter - diagnosing why there's that little black spot after only running for a few miles 1989 Jaguar XJS convertible - outside of air filter baffle and why it's got a smug of black after only being run a few miles (albeit really hard few miles)...
Lack of use, engine is busting to go places, and is breathing heavy.
Sadly, this is common on the V12 cars that, for some bizzare reason, dont get used very much these days.
City diving, killer for the V12, eventually.
Mine all had variations of that theme, but were all daily drivers, and the engine tuning was/is spot on, always.
We had very little, near zero, emissions stuff, so our engines were able to breath fresher air, and not rebreath their one stuff, as some markets are forced to do.
If that inner smudge is at the front, then that is where all the engine breathing ports are, and that would explain it.
So, what I'm hearing is that I need to tell the wife that I HAVE to drive the car LESS in the city and MORE on the open highways at 70+, right
Once my wife and I start really driving the beauty, do you think this will go away, or is it something that will always be there due to the stupid rebreathing effect?
The filters I removed prior to the one in the picture did not have the carbon soot, but that could easily be explained by the fact that the car just never probably got driven much at any speed.
It's coming from either the supplemental air valve (EAC 4161) or the other black hose right next to it which I haven't figured out what it is yet...
1989 XJS V12 convertible - supplemental air valve (top of picture)
Drive it more, and things will clear up over time.
That supplementary air Valve gives it away as the RH side (A Bank) filter.
Mmmmm, not common for muck in that one, the B Bank is usually the gooey one.
Down here that air valve was used for idle "kick up" for the A/C system, and sometimes? for the stupid 15 minute timer extra air, but purely a sucker, no matter the application.
Look back at the plumbing that goes TO that valve, look inside the hoses for oily goo, and keep tracing back. Maybe the PCV system is clogged up a tad, thus giving a back feed??
Ours get new filters every 2 years, and since I sorted the engine breathing even more, apart from good old Aussie Red Dust, not much else. Our driving is different too I reckon, once started, the V12's are usually on the run for at least 2 hours.
No idea what that other hose is, not seen it before.
The black elbow is coming from the air injection pump, I think it does air injection to the exhaust on start-up and then diverts the air to the intake afterwards. My 94 has a clutched air injection pump like an AC compressor, I think the earlier ones used a diverter valve.
Stupid crank vent. Install a catch can and drive it hard.
I accidentally kicked down / red lined my car yesterday onramp onto highway because some moron sped up, I swear it felt better after that black plume shot out the exhaust. Sounds contrary to modern advice but these cars really do need a solid HAMMERING on the throttle to reset things.
I'd be genuinely curious to see a slow city driven engine opened up see where exactly the gunk is collecting.
08-04-2020, 10:08 PM
Indications from an air filter?
