Friends though this has been addressed many times before, I am posting this just in case there is something peculiar to the 1998 XK8 and this can help someone else. Normally she starts every single time. Once in a long while I find I have to cycle through the ignition sequence once or twice to engage the starter motor. Everything lights up, seems OK, just can't engage the starter. Moving the shifter does not help. I always suspected this was related to battery charge level, yesterday I think I proved it. I was having a particularly bad day of these symptoms, it took 4, 5, or 6 tries to get the starter engaged, but it always did. I immediately put her on a charger when I got home, couldn't help but notice how many amps the fan was drawing after shutting the engine off. Well it showed full charge in short order - now not a single problem with the starter. Given the time it took to reach full charge, the battery was not very low at all, but she is working perfectly now. There must be a relationship-hope it helps you someday. John

 

The starter solenoid is a moderately high current device, it closes the circuit with the starter motor and engages the drive gear, together they pull around 400 amps! What is possibly happening is that there is not sufficient current to close the solenoid contacts and the motor is not being activated. The other typical problem is the not-in-park microswitch in the shifter is failing. If this microswitch is not working consistently, the car thinks the shift is not in park and it will not let the starter turn. If the switch is failing, slapping the shifter in and out of park a few times might rejuvinate it temporarily.

 

oldmotts, thanks for the idea but way too many high current items engage when I shift to run (fans, radio, headlights) for us to diagnose it as not enough current to trip the starter relay. Good news - she still starts perfectly. I hope I don't find out the hard way that these microswitches heading towards failure mode are voltage dependent. As I think about it that doesn't make any sense anyway right? A switch is either open or closed, its mechanical action has nothing to do with switched voltage. Well I'm sure I am over analizing it, thanks for your advice. John