Hi, I wonder if anyone can help with this intermittent problem I have on my 2002 XKR 4.0litre - Every so often, it may be a once in a hundred starts, then every 3rd try for a short time, I turn the key to start the car and the lights on the dash come on, the check reports no issues, but on turning the key there is no activity from the starter motor maybe 2 or 3 times, then suddenly it fires up as normal! If this was all that happened I wouldn't bother because it always goes in the end, but a mildly exasperating additional problem makes it a bit more worrying - every now and again upon turning the ignition key there is a graunching sound from over my right shoulder, either in the boot or somewhere in the cavity under the soft top, like a relay shorting-out kind of sound, and the car briefly loses its electrical supply, no lights on the dash, no power whatsoever to the car, resetting the trip computer, disconnecting the (aftermarket) stereo and necessitating re-inputting of all radio stations etc. The windows also need to be reset, and they have been playing up for a while, needing a reset every few starts as though the supply has momentarily cut out from the battery.
I removed and cleaned the earth connection to the battery and thought that had cured it (the battery is brand new) but it recurred soon after. I have changed the starter relay in the boot and that made no difference either
Any ideas welcome! Thank you.

 

It sounds like a bad connection. I would check the large fuse connection under the panel in front of the the boot. If the windows continually need to be reset it sounds like total loss of power. I would probably check battery post connections first for being loose or corroded.

Jack

 

Check the MEGAFUSE where the positive battery cable goes to the fuse holder.
I think there are two 250 amp fuses in the plastic holder assy.
The holder is forward of the spare wheel and battery.

The contacts are copper but look for loose or corroded connections.

 

What Bob said ^^^^^

Also check to see if your cables are heating up when you are trying to start it or hear the noise. That’s usually a pretty good indicator of a deteriorating cable. Good luck and let us know how you make out.

 

Thanks for your suggestions, everyone, I have removed and cleaned the connections on the Superfuse block and sprayed everything in sight with contact cleaner, also I removed and thoroughly cleaned up both battery terminal connections and the earth strap to body connection from the battery. I did notice one of the superfuse nuts wasn't very tight, but they all are now! since then, so far, so good, I have started the car a dozen or so times and it seems fine, and I haven't had to reset my windows (yet!), so I will report back again later, either way, when enough usage has proved whether or not that turned out to be the problem - Thanks again!

 

Well done....

 

Sometimes big problems aren't so hard to remedy I'm sure you're feeling a whole lot better. Awesome, fingers crossed.