More likely the O ring seal in the bottom part of the oil filter casting area. See this diagram:

Parts 13 and 34
https://parts.jaguarlandroverclassic.../brand/jaguar/

 

Now I am bloody confused, and maybe I need to start drinikng again, NAH.

That idle srew has NOTHING, ZIP NADA to do with COLD IDLE.

That is purely the cut outs of the AAV "mouth" and the gap of the piston when fully down, AKA wide open.

That screw is used to control the air bleed through the cast channel of the AAV once the piston is fully closed.
Read my PDF, I believe I expalin it for easy understanding.

It matters not how many turns OUT it is when at Operating Temp, that is dictated by what the WANTS to run at the revs you desire, nothing else.

As I said, MOST of mine were around the 2 turns out. One was close to 3, but she was a Blonde, nuff said on that.

Remember, I dont run any of this "stuff" on any of mine, I woke up long ago.
No AAV
No Balance Pipe
No Over run Valves
No PCV.
No Aux Air Valve
AJ6 throttle discs
ONE ONLY vac line TO the advance capsule..

ALSO
They were/are Daily Drivers, and I had NO time, less than zero, for this unreliable nonsense, so to work I went, and never looked back. Many have followed, and NO, I am NOT special, just a Grumpy Old Aussie, who did insane kms per year. We be a a HUGE Island, lots to see, and we seen most of it. Last Road Trip, 25000kms, in 2 years in the 85 XJS. Only issue as an Idiot Oil Light Sender weeping, so local Toyota Dealer in Dubbo (Google if to want), and got one for a Corolla, still in there today.

 

nothing to do with the cold idle, yes. i am happy with that, i am only talking about hot.

todays discoverys:
The suspected leak when blocking the filter cases and it keeps running comes from the filter case itself and is bot a problem then. Sealed it with tape for a test and the rngine stalls right away.

I then switched back to the original PCV valve - the old one not the new spare part one. Now i am at about 4 turned out and 800rpm idle. I suspect the spare PCV valve just let in more are. And the ford one does not work and causes major oil leak....wich is also gone with the original one.

So after all that i think i can cross the vacuum leak off the list. The idle is still rough though. I am not sure if its the one injector - you can feel misses on both exhausts.

Anyway, when i replaced my temporary fuel line installation (wich i dont trust for too long) with a decent one i will take it for a long drive through the mountains and afterwards look at the plugs again. When the one from last time is different again it gets a new injector and a new wireing loom. If not - just a new wireing loom.

 

Today i took it for a 200km ride through the mountains and it drives really well. Two things i noticed:

Sometimes it idles almost smoth, sometimes it idles a bit rough. Not as bad as befor i threw the pressure regulator out. But when it idles amost smooth it idles at 950rpm and when its rougth it idles at 800rpm. It feels like after a hot start it runs at 800rpm and then slowly over a few minutes climbes to 1000.

The other thing is: It now starts perfectly when cold...better than every new car. It also starts perfect when hot. Unless it stands for an hour hot and then i try to start it. Then it needs a slightly open throttle to start, otherwise it doesnt start at all. No fuel line priming etc helps there.


EDIT: after reading and thinking and going through the shematics i think it is like following:
On cold the AAV is open, it gets air and it starts fine. When hot it gets most of the air through a vacuum leak and it idles okayish because the hot engine draws a lot of vacuum. The AAV is fully closed (i checked that).
Now when i start it hot the AAV is still fully closed so it needs to suck the air to start through the vacuum leak - and thats not enough since it doesnt build such a vacuum while cranking.

The lower idle and the increase later may come from the Fuel Temperature sensor, that enriches the mixture due to the hot fuel rail.

does that make sense?

I have to get a smoke machine or something to find that leak....

 

The AAV when closed as it should Hot, has, by deign, the Intake air entering via the Idle Screw By-Pass cast passage, and the Idle Screw is the restriictor to give the engine the idle speed required, thats all it does.

That Hot fuel Rail sensor simply closes the Vac supply to the actual FPR, B Bank, to raise rail pressure to about?? 42psi, thus aiding the purging of the air that is now in boiling fuel inside the rail. Thats the theory, and seemed to work. For some reason we missed that item, and with 40C and more Summers, we have no issues, or rarely issues. Ageing Fuel pump, EFI loo\m, TPS adjustment, etc all cause issues with Hot starting down here. Putting a small vac hose from the Intake spigot TP the FPR, and see what changes, is simple, and free. If it works better, leave it alone, and tidy up the left overs.

Double check, or more, the throttle disc clearances, and ensure they are 0.002" at the BOTTOM edge.Thanks for the error spotting Greg., hence this edit.
On cars here with an AAV still installed, I set them at 0.003". Ensure they are CLEAN, and I mean CLEAN, as the dredded V12 emissions Goo reeks havoc with Hot idle.

Remember, this is a Double Six, and that requires these things to be balanced as designed, so the 2 engines dont fight each other. Once over 1500rpm, it matters way less.

 

Grant
Bottom edge?

 

OOPS.

Greg is right, and now I owe him another beer.

EDIT DONE.

 

aye i need more or less alcohol, the current level does not work.

i double checked the throttle disks. They are fine - i adjust them that i can pull out the feeler gauge with reasonable force.

Then i really did get hold of a smoke machine from a local oldtimer shop. Filled the inlet with smoke....and found nothing. only thing where smoke leaks out is the distributor cap and the filter cases.
First i thought i am dreaming but then realiced that the smoke got over the AAV in the distributor ventilation.

but no leak to be found in the vacuum section.

 

This is because after a hot stop and enough time, the fuel in the rail evaporates and the injectors do not spray until the vapour is purged - which takes time. Shortening the injector flexibles to minimise the length between the spigots on the rail and the injector helps hot starting enormously; though opening the throttles, as you have found, also helps. This is not a fault symptom, rather a feature!

 

ah yeah the hot start issue.
yes the evapuriced fuel was my first thought as well. but shouldnt priming the fuel rail several times also fix the problem? i tried priming it 5 times without success.

i have a electric fuel temperature sensor btw. - thats the only thing i can think of that the rpm rises after a few minutes instead of falling after a hot start

Im still a bit confued about the PCV since thats a huge vacuum leak. Do you guys agree that engine should run at 400rpm just the air over the PCV? thats normal? I wonder since the PCV is never mentioned in any other thread about vacuum leaks and thats a huge built in vacuum leak.

 

Please explain exactly what you did when you "blocked the filter cases". Which side, both sides and how? And when you say the leak "comes from the filter case itself" what exactly do you mean? For example, if you tape off the throttles, does the engine run?

There is one hose, impossible to see unless the B bank air filter box is unbolted, which is connected to the AAV and the distributor ventilation system. Worth checking if it is intact, or if the ventialtion spigot has broken. See items 4 and 5 in this diagram:

https://parts.jaguarlandroverclassic.../brand/jaguar/

 

ah yeah the hot start issue.
yes the evapuriced fuel was my first thought as well. but shouldnt priming the fuel rail several times also fix the problem? i tried priming it 5 times without success. No, for some reason it does not work. Shortening the injector hoses does work 100% as I have recently proved.

i have a electric fuel temperature sensor btw. - thats the only thing i can think of that the rpm rises after a few minutes instead of falling after a hot start I doubt that makes any difference, but you can prove it by diisconnecting it and seeing what happens.

Im still a bit confued about the PCV since thats a huge vacuum leak. Do you guys agree that engine should run at 400rpm just the air over the PCV? thats normal? I wonder since the PCV is never mentioned in any other thread about vacuum leaks and thats a huge built in vacuum leak.[/QUOTE] No, you have a leak elsewhere IMO!

 

I blocked the filter cases by hand on the inlet. Both inlets with a helper.
The cut between the two parts of the filter case, wich is sealed by the rubber of the filter itself draws air when i block it. But that should not effect the vacuum.

Good hint with the distributor ventilation line. When blocking the filter case it can get air over that line into the filter case.

I blocked the whole filter case because i noticed blocking the holes inside does not proper seal them because the filter case has a double backplate where air still leaks through.

 

This will not block any vac or other leaks which will all be unaffected by the hand over the intake trumpets. The filter boxes themselves are not that airtight.

 

To clarify:
If the PCV is ONLY connected to the crankcase with no leaks in the system, the car will not run.
If, however, there are leaks in the system (eg flexible hoses, pig snout seal, etc etc) then as the PCV tubes are connected to the manifold inboard of the throttle butterflies, then the engine might run.

 

The PCV is in a chamber at the air filter case wich is connected to the crankcase and has a hole to the airfilter. The PCV can always freely breath through the airfilter and therefore is a huge vacuum leak no matter in what condition the hoses of the crankcase breathers are.

Thats why i asked...how much air gets through there highly depends on the spring load and type of the pcv. the two original ones i have from jaguar are basicly a 8mm hole right through without much resistance.

 

Just reread the thread. Am I correct in understanding that:

• there is no longer a vac leak and that the high idle is because of the PCV valve?
• Secondly, the stronger PCV valve causes the engine to stall and the oil to leak?

 

Ok so there are three ways for air into the Engine. First the Throttle bodies, then the AAV and the PCV.
So today i put off the filters and sealed the Throttle disks with tape. Then i put out the PCV and replaced it with a plug. And last but not least i put off the input pipe from the AAV and put a plug in. It should be a sealed system then.
I put the vacuum hose off the Vacuum switch and put my pump with smoke on it.

I found three very minor leaks. One at the vacuum connection at the top of the right throtte body, one at the knee hose between AAV and manifold and one between balance pipe and manifold. The last two leaked between the pressed in pipe and the manifold....not at the rubber hose. So i sealed them with a engine gasket sealent and put everything back together.
I also noticed that the throttle shaft seals are leaking smoke. maybe i have to replace them? or do they seal at vacuum and just dont seal at positive pressure....or are not 100% air tight anyway?

So afterwards i put the plug out of the AAV, unsealed the throttle bodies. I regapped them a bit more to the thight side and started it. The AAV is open there - i checked with a mirror.
It did not start without the PCV. So i put back in the PCV and started it. It idled at 700rpm cold with the idle screw all in. So i adjusted the idle to about 1100rpm and let it warm up. I looked at the AAV several times and it closed completly when getting warm....surprisingly without change in rpm.

so i put the idle screw back in all the way and it gets down to 800rpm. The AAV still takes some air through it - not much but when i plug the inlet the idle drops about 100-200rpm.
When i block the PCV it drops about 400rpm. When i block both it stalls.

So two things puzzle me....why is there no change in rpm when the AAV closes? it seems like the piston has no effect at all. I can adjust the idle cold with the screw and warm. And why is most of the air going through the PCV and not the AAV?


edit on your question: i put in a PCV valve that closes at high vacuum and that drops the rpm by 400rpm and causes oil leaks yes.

 

That summary of yours seems to me to indicate the engine is working perfectly!

The AAV is open when the engine is cold; and this allows air through the AAV in two ways: i) via the thermostatically controlled cylinder and ii) through the idle speed adjuster channel. As both the engine and the coolant are cold, the engine has more resistance to turning over, so extra air is needed to overcome this resistance.
As the engine warms up, the resistance lowers and the AAV cylinder gradually closes, progressively reducing the extra air as the engine resistance to turning also reduces.
If this happens as it should (and as yours is, from what you have described in the above post) then the idle stays the same.

The PCV is designed so that, in conjunction with the AAV, the idle level is as it should be.
So this seems to have solved the problem?

 

But i thought the cold idle should be higher? at about 1000-1100rpm?
And i reach the hot idle at 800rpm only with the screw all in.