Jaguar V12 Idle Issues - Checking AAV and adjusting idle - How to tune a Jaguar V12 Part 4 

I'm really glad I could help!

Yes he’s a great guy!

Yes it is. One would think that too but they went with 60's and 70's technology. It is very reliable but off course after 40 years they do need attention. It's always a lot more fun to rebuild original items 😊

I'm really glad you enjoy them! Sounds like a great friend that talks you into buying an XJS. Let me know if you need any help

I find the most common reason for the engine quitting is a bad connector on the front of the B Bank ( Drivers side n.america) water temp sensor. It's not the gauge sensor which is on the A bank but this one is for the ECU so that it knows the engine temp and the fuel mix. I've had two V12's and this has been a problem on both. Another slightly less common problem is the ignition module. I think the 1990 has a later system ( Minarelli) but the late eighties used a 1985 Chevy Blazer HEI module inside the box which is about 20 bucks froma Napa store. Third problem maybe a bad fuel pump. I'm just basing my answers on my own experiences but thee are common problem areas.

@@motorcyclementor1785 Would these solutions also work for a stalling Pre-HE V12 after starting the engine for the 2nd time when still warm?

What a score! I do have a few extra ones also. You never know when you'll need a new one. My rebuilt one works very well now

Thank you for watching Stan! I hope a rebuilt AAV will fix your high idle issues

Thank you Chad!

My car was surging as well

You're welcome! Glad you enjoyed it

Yes they do. I plan on showing that when I go through the vacuum lines on the HE. There's a lot of them! Thank you for watching

I'm glad your car is running better now! Hope you can enjoy it on the road soon

O yes, and driving almost every day, my most surprised is corvette and BMW's looking at me, either they saying what a great car, or I'm crazy on maintenance this car

I think they are admiring your car

ok now I know what to look for and test it, thanks

Haha thank you! Have to be sneaky sometimes

Thank you! I have sometimes removed the air box completely, it does make it a lot easier then. Is your new one working well?

@@LivingWithAClassic The new one is working well! Car starts easy and the idle is now set low and nice. I do however have a slighty rough idle, additional work do to :-)

@@Lemuren77 The adventure continues!

Very simple, soak new hoses in very hot water to soften them to flex.

Thanks for watching!

Thank you for watching!

I'm not sure about the factory hole in the hose. What year is the car? He does rebuild them for all the years. He makes new parts and adapts them for the different parts. Hope that you have a good New Year also!

Gene, the "hole" that you are referring to is for connecting the pipe or tube coming from the top of the distributer cap and acts as a breather pipe for the distributer, without this you are risking a explosion in the distributor. The pipe was originally connect to the larger pipe via a plastic/nylon connector, these though go brittle with age and heat and break. However, when mine disintegrated last year, I used a short length of brass tube about 1/4" in diameter, available at your local model shop and some vacuum hose of a suitable size an length. To fit the brass tube into the larger pipe will, I'm afraid entail at lot of fiddling about. I did mine with the inlet manifold already removed but, in you case I expect, it will entail removing the air cleaner and removing the larger pipe from the AAV. Ensure that it a tight fit in the tube, use a smear of "Vaseline" or washing up liquid to help it into the hole if needs be.

@@jongodsell88 Thanks Jon for info my XJ12 is a 1987. I see the hose going under the manifold and hose does not seem loose. I will remove air cleaner and check. I did get a used AAV from local eBayer . A job to install with that rubber elbow..trial n error...hours later success. Jag starts perfectly, perfect cold idle and warm idle too. Now the cat goes like a leaper. Oh the AAV cost me $75 and did kitchen water test like Adam said. Boy we are lucky to have his videos.

@@genemccormick7567 In my ’88 convertible, there is a short rubber extension in the pipe that has been vulcanised in position, almost in line with the distributor, and it is from here were the vac line (I suppose you could call it) runs from the top of the distributor cap. The tube should not, of course, be loose and should be secured to the AAV by a Jubilee clip. To removed mine, I took the easy option and just cut it off! As the was a new one in the water hose replacement pack. A deal of persuasion was required with a broad bladed screw driver and petroleum jelly, was required to make every thing return to their rightful place; the secret I think is to keep everything slack until the AAV is in securely position and then tighten the Jubilee clips.

@@jongodsell88 Jon I did trace that hose from distributor cap and it goes right into air cleaner alloy base. Since I replaced the AAV and elbow rubber the V12 idles perfectly and same when warmed up. On drives perfectly and does not miss a beat. When I removed the AC and non used bellows unit I found two spark plug wires sparking. Replaced them. This was done before I had AAV problems. Thanks to Adams youtube video on the AAV it showed me what had to be done. Adams fuel injector replacement video makes me to inspect the rubber hose on each injector a regular thing. Rockauto have rebuilt injectors for Jaguars by Reman with hose and 'o' ring for $36.78 Canadian or $25.00 US. Of course you would need 12. That injector kit Adam used is very reasonable price wide but' a lot of work.. We see a lot of new vehicle on fires on TV thinking its all that plastic under hood. Well all of todays cars.SUV's and trucks are fuel injected. Too bad they didn't make a V12 with carbs like my 1976 XJ6 I would feel a lot safer. Rule of thumb open your garage doors and after starting V12 get it outside just in case. Thank Jon for your assistance. Gene

Only a very small amount comes out

@@LivingWithAClassic thank you, then i will include it in my winter check up

He sure is!

Start the car from cold, idle should be around 1000-1200rpm, after about 2-3 minutes you should notice it starts dropping slowly, eventually after 5-6-7 minutes it should drop down to 700rpm or whatever it's set to using the bolt on the aav.

I'm very glad you like them! Yes it sounds like it could be an AAV issue. If it is stuck the idle would be too low all the time and especially when just started.

Maybe you have a vacuum leak somewhere? I'd start to check that before messing with the AAV again

Mine was revving high too ( almost 2000 rpm ) and so I removed the intake hose from AAV to manifold and stuck a cork in the manifold. Not an elegant solution but a good temporary measure. It's starts easily and idles perfectly. Just give it a whiff of throttle when you crank it.

Yes, called the AAV on the V12

I will message him now and see what happens. I’ll update you