XJ6 & XJ12 Series I, II & III 1968-1992

1978 Series 2 V12 Engine Mis-Fire

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  #61  
Old 02-02-2016, 06:06 PM
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Oh, isn't THAT the truth, Grant... all that race car crap, just doesn't belong here.


Did a couple more adjustments. Engine runs very nice, for about 10 - 15 minutes of low speed in town. Then starts it cutting out ( no fuel ), crossing to over fueling. Lean out the MPS, so it will idle again... and the cutting out ( no fuel ) gets VERY aggressive.
EVERYTHING about this condition, points to big gulps of air within the pressure side of the fuel system.


I may have found an affordable part in the States. I'll check.
If not, we should see what your Australian money will cost me ? !
 
  #62  
Old 02-02-2016, 06:15 PM
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OK may i ask ,have you measured the fuel pressure before and after the FPR, regulator??
 
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  #63  
Old 02-02-2016, 09:46 PM
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GRRREAT question, Ron !... and good idea.
I will do that tomorrow.
 
  #64  
Old 02-04-2016, 03:17 PM
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pic of my pump& filter setup, 1/2" aluminum hi-pressure lines,Aeroquip, and 3/8" return line low pressure back to tank.

on my system you can barely see the low mounted fuel/ air seperator tank, the small line lets rising air bubbles return back to the main fuel tank, pure fuel is drawn from the bottom of the small tank, its Jags idea.

my pump and system is way overkill, but thought back 20 odd yrs, i may turbo/supercharge the V12 and need a hi/volume system! may as well do it while the money was flowing!

also pic of FPR (fuel pressure regulator) adjustable. fitting for gage on the front of left fuel rail, barely see it,(quick connect).
 
Attached Thumbnails 1978 Series 2 V12 Engine Mis-Fire-trunk-xjs-fuel-system-union-jack-001.jpg   1978 Series 2 V12 Engine Mis-Fire-jag-strut-brace-mom-ridin-shot-gun-v12-exhuast-mani-009.jpg   1978 Series 2 V12 Engine Mis-Fire-jag-strut-brace-mom-ridin-shot-gun-v12-exhuast-mani-001.jpg  

Last edited by ronbros; 02-04-2016 at 03:21 PM.
  #65  
Old 02-05-2016, 05:02 PM
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Sorry for the delay responding, Ronbros....
I'm still trying to comprehend what you've got going on there. Makes me feel VERY inadequate !


BTW, looks like it's confirmed. I find no symptom / problem with this car, other than the fuel "foaming up" within the pressure side of the system, after the engine runs for more than about 10-15 minutes.
 
  #66  
Old 02-06-2016, 10:29 AM
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i have seen that very sympton occur when there is a restriction at the beginnig of the fuel system, like a partialy plugged pickup screen or crushed fuel line!
basicly any form of restriction can suck air into the system from a microscopic opening that is before the pump!
 
  #67  
Old 08-21-2016, 10:15 AM
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Default August 22 2016 update

Sorry for the delay, people. I seriously put this thing on the back burner for a while.


HOT fuel
shielding missing underneath... where the fuel line is 1" away from the exhaust head pipe.
Made a shield.
A/C system is not charged, or operating at this time. I by-passed the return through the A/C "log".
HHMMM...
a bit better.


Disassembled the distributor. Found a problem, where the trigger board had been "contacted" by the three fasteners underneath... and had made their mark.
Re-mounted it slightly higher.


It appears that it is finally fixed.
No more chasing the MPS setting.


I'd still like to replace that trigger board though.
 
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  #68  
Old 08-21-2016, 10:23 AM
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Kudos:

At long last, the end of that trail.

Enjoy the fruit of your labors.

Carl
 
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Old 08-21-2016, 10:37 AM
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thanks, Carl...
unfortunately, it looks like I have to sell it now.... along with three others.
 
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Old 08-22-2016, 09:28 AM
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Acquired another set of wire wheels, and installed them.
 
Attached Thumbnails 1978 Series 2 V12 Engine Mis-Fire-1978_jaguar_xj12l_blue_wire_wheels_aug152016rfup35.jpg  
  #71  
Old 08-24-2016, 12:04 AM
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Well, I drove the car a bit more. Yes, it's pretty good... but.... when it gets warmed rigt up on a hot day, it acts up again.
So, I got focused, and searched. I mean REALLY searched !

AHAH !!!!!!!!!!
I FOUND ONE !!!!!!
A GENUINE JAGUAR, BRAND NEW........... 4 WIRE TRIGGER BOARD !!!!!!!!

Ordered today, should be here in about a week.
Unfortunately, it cost me almost as much as the car did....
ok, so I'm exaggerating... a bit anyway
wow
lets not damage THIS part
 
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  #72  
Old 08-24-2016, 09:29 AM
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Aw: But, is not four VC12 Jaguars far more than one man can handle?


So, you can sell off three, pad your depleted pocket book and have one left to "enjoy". Not all that bad....


Carl
 
  #73  
Old 08-24-2016, 11:03 AM
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That's the plan, Carl. Can't sell the "C" though.
I hadn't mentioned... I acquired this one a couple months ago:
 
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  #74  
Old 08-30-2016, 06:36 PM
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Default FINALLY... Ready to go

I received the new 4-wire trigger board today. It came with a new rotor as well.
VERY carefully installed it, making sure the rotor was the correct distance above the board ( .030 to .090"... mines at about .062" )
the magnet on the new rotor, was much stronger than the old one.


anyhow


done
It's as it should be.


A couple photos:
the old and new part
and, the underside of the new part.
 
Attached Thumbnails 1978 Series 2 V12 Engine Mis-Fire-dsc000062.jpg   1978 Series 2 V12 Engine Mis-Fire-dsc000032.jpg  

Last edited by XJ12C_Driver; 08-30-2016 at 06:38 PM. Reason: forgot the photos !
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  #75  
Old 08-31-2016, 07:08 AM
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Well done.
 
  #76  
Old 08-31-2016, 10:38 AM
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How many of those gorgeous cats roam your part of the world???
That red one is a beauty.


When do we get to see the "C" and your attention to it's needs?


Carl
 
  #77  
Old 08-31-2016, 12:23 PM
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Well, Carl, here in Alberta, with the exception of this summer ( I believe to be the worst on record ), it's a pretty dry prairie environment. Two long time, Jaguar dealers, and the cars survive pretty well. So, there are some around. However, solid series 2 cars, especially V12's. are pretty scarce.


The maroon one is not as nice as the photos suggest... though it IS my favourite colour on these cars. Lots of chips, scratches, minor little dents, and some rust. Drives as new.


My "C":
Had a 3.31 open rear... I installed a 2.88 power lok.
( originally a 4.2... getting a late '93 6 litre )
If I can swing the 5 speed manual conversion, I'll install a 3.31 power lok.
 
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