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The mkiv Supra Owners Club

Jag XK8 issue


Kirk

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Heres 1 for you guys!

got a jag xk8 of my mates dad, been running perfectly, start 1st time everytime.

Anyway he goes to start it next day, wont fire. So i get a call from him and i go round and see what it could be. cranks it, wont fire, so im guessin hes probly flooded cylinders. Had 1 more try and then the thing popped through the air box with enough force to split it in 2!

So i pulls plugs out, gives it a pretty good blow out, pulls the pump fuse crank it a few times and then pop a new set of plugs in, crank it.... wont fire, checked for spark, got a spark but it just will not go!:banghead:

Pops again, a bit louder this time, so i called in my mate to plug it in, comes back as crankshaft position sensor fault!

So i go and pull that out, its pretty beat u but interestingly enough its had 1 before, how do i know? well lets say the lazy bastards couldnt actualy be bothered to remove the old 1 from its clips and left it dangling and instead routed the replacement a different way.

So i replace that! brand new from jag, suprisingly cheap, put it all back together, cranked it......... NOTHING! now its realy getting on my tits!!:angry:

Im just wondering when it went pop the 1st time its managed to throw the timing out or maybe bent something? i cant see it of doing personaly but you never know, im gona compression test it tomorrow and see whats what but anyone have any ideas what it could be???:shrug:

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OH DEAR my friend, i work for Jaguar so i will just explain a few things..

 

Ok right, im guessing you have a early XK8, about a P reg ??

 

In 1998 the xj8 and xk8 engine bores had Nikasil linings, The Nikasil was vulnerable to erosion by the sulphur in petrol

 

Jaguar recognised this as a problem and have been replacing engines up to 5 yesrs old, or less than 100K miles (whichever earlier).

 

Im sory to say this but from the sound of things you need a new engine..

 

If this is the case Jaguar are still kinda doing a deal on this, they will pay contribution to the engine if you want to go down that road but to be honest its prob not worth doing now..

 

If you want it started, do the same thing, clean the plugs, dry them out and put a drop of oil in each chamber as you have lost compression and it should start with a big cloud of smoke...

 

I think you can check by the last 6 of your vin to see if you have that type of engine...yours will start like 003456 or A09456

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or...

 

You could have a snapped cam or secondary timing chain. Ive had that before on an early 4.0 XK

 

Take the Cam Cover's off, weirdly the 3 car's that have done it for me, have always been on the passenger's side bank, BUT it could be the other side

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I wouldnt go buying a new engine just yet, these cars had a flooding issue. Once they were flooded they were notoriously hard to start. The AA/RAC had a note sent out exactly to this effect.

 

When mine did this (a couple of times) it took the RAC guy ages of cranking over with the foot to the floor (make sure you lift any mats etc) he even had to put some leads on from his van as it flattened my battery, but it eventually spruttered into life.

 

One tip, never ever start one of these, move it 2 or 3 feet then turn it off.

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Yeah they do flood, But if its got enough pressure back towards to blow an airbox, then i dont think its flooded.

 

You could just pull the Relay (in the boot fusebox, next to battery) at the top, the middle one... They're layed out like a T Shape, Crank it untill it starts, then let it cut out, slap the relay back in and it should start - if it's flooded

 

God, the ammount of these and XJ's we had on the back of a flatbed was unreal, Easy money though :D:D:D

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cheers for input fellas. it is an r reg XK8

gonna check the compression shortly with me mate, had a few cranks again this morning with plugs out, definatly compression there. once its been checked ill know for sure. if not then ill start pulling the timing covers off. It just seems so strange that all of a sudden its just happened. He's rarely had an issue with it since he's had it. Just doesnt make sence at all.

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Let us know how you get on, i know where my money is im affriad but i hope its something simple for your sake, Its just we used to get this all the time in our dealership, wont start, blows the airbox up..all the tail tail sighns

 

When the Tecs here a bang from a old xj or old xk8 they all shout ENGINE!!! LOL

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Compression numbers as follows

Bank 1 (drivers side)

cylinder from front to rear

number 1 - 79

number 2 - 0

number 3 - 81

number 4 - 85

 

bank 2 (passenger side)

 

number 1 - 78

number 2 - 78

number 3 - 75

number 4 - 80

 

very low number and very inconsistent... doesnt look good

Im gonna check the timing marks with TDC, im thinking chains jumped personaly

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well i checked the timing, a wopping 10 degrees out... :blink:

i know it probly is just nackered but i thought id give it one last go.

ive retimed the engine to spec, pulled plugs and cleaned them up, there drying as we speak, blown out the bores and that let it all dry out over night.

Ill drop a bit of oil in with the plugs before hand and give her 1 last try.

such a shame, is a rather nice motor, hate it when you cant fix something when asked cause its that badly gone but the owners a sound guy and is prepared to bite the bullet should it not go, hes paying me for all the time ive spent on it so thats an upside :)

cheers for the input guys, ill let you know how it goes tomorrow!

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well i checked the timing, a wopping 10 degrees out... :blink:

i know it probly is just nackered but i thought id give it one last go.

ive retimed the engine to spec, pulled plugs and cleaned them up, there drying as we speak, blown out the bores and that let it all dry out over night.

Ill drop a bit of oil in with the plugs before hand and give her 1 last try.

such a shame, is a rather nice motor, hate it when you cant fix something when asked cause its that badly gone but the owners a sound guy and is prepared to bite the bullet should it not go, hes paying me for all the time ive spent on it so thats an upside :)

cheers for the input guys, ill let you know how it goes tomorrow!

 

Cant see the timing being out if it has not been touched as its timing chains but yea keep us informed how it goes mate

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Well after all my hard work and effort she sprung into life, breifly, its gone.... such a shame realy

I understan where yourr coming from mate, dint make much sence to me either but i checked and verified, 10 degrees out.

On the bright side ive spoken to jag and there going to do a 50/50 with the owner for a new engine!

help and as advice truely appriciated!

cheers guys :)

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No probs mate, thats the problem of geting a early xj8 (308) or xk8, a large portion of them had this problem so make sure you get the later ones or make sure that its had a replacement V8..

 

You want the new XKR 5ltr..500bhp mate, there are quick! lol

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