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Thread: XJ8 Not starting, I have spark and fuel pressure.

  1. #1
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    XJ8 Not starting, I have spark and fuel pressure.

    Hi all,

    New to this forum after previously fiddling with older cars (Hoping this is as good and friendly as the highly active 'MG Experience' forum!)

    Several weeks ago I moved my '98 xj8 around the driveway, I only had it running for about 30 seconds before switching it off. The next day it just about started, it sounded like it wasn't running on all 8 cylinders then died almost immediately. It will now crank but will not start.

    I have about 40 PSI of fuel pressure, I checked one of the injectors and there was voltage across it when cranking (approx 6-10V).

    Plugs are VERY tight - don't want to risk removing them for compression test.

    I put a spare plug in one of the leads and it is sparking.

    I'm thinking that running it for 30 seconds has caused the dreaded 'bore wash'. I have tried cranking with throttle wide open (i.e. injectors closed) to clear this but it hasnt helped.

    I cant really put oil in bores to help compression as I dont want to risk stripping threads with tight plugs.

    I should add when cranking it i noticed a 'traction control failure' message on dash - but this could be due to lack of voltage to control unit during cranking (?)

    Also, the alarm started playing up not long before I last drove it (randomly sounding, so I've just left it unlocked)

    It has previously very occasionally been reluctant to start, but would always start after second try.

    Do we agree this sounds like bore washout?

    Many thanks in advance for your thoughts.

  2. #2
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    I had a similar problem with both my S-type V8 (2001) and my XJ8 (1999). If left for any length of time they wouldn't run. They would eventually fire, but immediately die. In both cases it was nothing to do with the dreaded bore-wash. It was because the immobilizer was out of sync as the cars had been left unlocked. I overcame the problem by fully charging the battery (Jags need a good battery) in each case, then replacing them and closing up the car and locking, then unlocking, getting in and turning on the ignition, trying to start it. If it didn't start I switched off, got out, locked up, waited a few seconds, unlocked, got back in and tried again. Kept doing this for 2 or 3 times and eventually they both fired up and ran. I have also solved this problem another way, by connecting the battery to a locked car. If the alarm goes off, and you click the key fob open button, the alarm will stop and the car will then fire up when you try starting it. Try both of these, If they don't work, then you can definitely say it's bore-wash!

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  4. #3
    Senior Member Andy K's Avatar
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    I would start WD40 the plug threads. You will need access on a 1998 jag!

    Maybe leave it a week, and see if you can get it started. Get the engine hot, this helps plug removal a lot and more wd40


    yeah and charge battery!
    XJR 2001 Pacific Blue
    Range Rover Sport 2005 Red 2.7 TD

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    Sounds like bore wash to me. Leave it a few days, charge the battery up and foot to the floor when starting it and keep the foot on the floor.

    I wouldn't worry about the traction message on starting. Mine occasionally does that and the battery is fine.
    Present car: 2000 XJR Platinum Silver 228,000+ miles

    Previous Jaguars: 1977 XJ6L 4.2
    1985 Daimler Double Six V12
    1990 Jaguarsport XJR 4.0

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  8. #5
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    UPDATE:

    Thanks guys.

    I charged the battery and tried the old 'foot to the floor' method with no luck.

    I decided to put oil down the bores.

    I tried WD40, then some penetrating oil to remove the plugs, but neither worked - in the end I just grit my teeth and used an 18" strongarm - fortunately I caused no damage.

    I used a syringe and put about a teaspoon of motor oil in each cylinder.

    With the injectors disconnected, and my foot to the floor, I cranked until it sounded 'compressiony' - I then connected injectors and cranked with throttle about half open - I think it took a couple of goes but it came back to life again.

    Its an interesting point one of you raised about the imobiliser/security system - I didnt see your message until after I had got the car running again, and although It didnt seem to have anything to do with my issues, I have been leaving the car unlocked due to the alarm randomly sounding (I think it may be due to a bad sensor on one of the doors or something...)

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    I had bore wash on my (now departed) 3.2L x308.
    First time was my own ignorance about bore wash when I was moving it around the driveway to wash it.
    The second time was because it stalled several times on starting.
    The third time was caused by a so-called Jaguar specialist who had never heard of bore wash.
    On each occasion I noticed that the engine turned over really very fast (due to the lack of compression).
    All except the first (warranty) I had to pay for. I do my own maintenance these days.
    2005 3.0 S-Type (and 2000 3.0 S-Type)
    Retrofitted: CD Changer, Bluetooth, Voice, Sat Nav

  10. #7
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    Quote Originally Posted by jaidank View Post
    I had bore wash on my (now departed) 3.2L x308.
    First time was my own ignorance about bore wash when I was moving it around the driveway to wash it.
    The second time was because it stalled several times on starting.
    The third time was caused by a so-called Jaguar specialist who had never heard of bore wash.
    On each occasion I noticed that the engine turned over really very fast (due to the lack of compression).
    All except the first (warranty) I had to pay for. I do my own maintenance these days.
    Does a tendency for the bore wash issue tend to suggest an engine is on its way out? I don't know how much it would cost to rebuild one of these, I would do all the labour myself (apart from any machining etc. required)

    I don't want to encounter it again so I am tempted to use a thicker oil at the next change. not sure if this is advisable or not...

  11. #8
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    My XJR was quite prone to bore wash when I first bought it with 160,000 miles on the clock. Since replacing the O2 and MAF sensors it never happens now, and the cars now done 230,000 miles
    Present car: 2000 XJR Platinum Silver 228,000+ miles

    Previous Jaguars: 1977 XJ6L 4.2
    1985 Daimler Double Six V12
    1990 Jaguarsport XJR 4.0

  12. #9
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    Quote Originally Posted by Bob1198 View Post
    My XJR was quite prone to bore wash when I first bought it with 160,000 miles on the clock. Since replacing the O2 and MAF sensors it never happens now, and the cars now done 230,000 miles
    Great stuff, my X308 (the one in OP) occasionally struggles to start and it seems to be when its warm (for example after being in shops). I think this is a crank position sensor issue (I had similar in my Volvo 940).

    Do you think the failing o2 and MAF sensors in your car were causing general starting/running issues which led to the engine flooding and bore wash? I'm just trying to put two and two together how the issues are related..

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