I wonder if any of you guys can help me with a relatively minor, but slightly concerning, issue with my 2001 308 XJR.

I have owned the car since October 2013 and it has always started pretty much on the turn of key, hot or cold. However, recently, it has been reluctant to start and turns over for 2 to 3 seconds before firing up, with no warning lights. Once started she runs like a dream and performs as you would expect a good XJR to do. Run her around to get warmed up completely, turn off the ignition and on again, results in the almost instantaneous start as before the ‘fault’ appeared. But leave the car for about half an hour, i.e. still warm, and the 2-3 second turning over before starting comes back again. Odd or what?

So I trooped off to my local independent specialist - Keith of many many years experience with Jags - plugged in the diagnostic kit. Which found no faults whatsoever. A bit of head scratching ensued after which Keith suggested the spark plugs were replaced as they sometimes 'get tired', even though the car has covered just 55k from new.

Spark plugs replaced. Made no difference.

I have subsequently changed the battery. No difference, apart from turning over faster. I have also changed the batteries in the key fobs just in case it was a weird problem with the immobiliser or something like that. Made no difference.

Have anyone experienced this problem? Any ideas what might be causing it, or suggestions of what I or Keith should try next?

Your help is very much appreciated.

 

Hello and welcome to the forum....

Couple of things to check, the XJR has 2 fuel pumps, you could have a failing 'start' pump and the car switches the 2nd pump (which chimes in at 3000rpm). Search for XJR fuel pump and testing in the forum for more info.
A number of cars have been cured of hard starting by replacing the water temp sensor, if this is failing the ECU will not know what fueling to deliver on crank.

 

Thanks Sean. I'll try the coolant temperature sensor first.