hi all having a problem with my wife's 2000 xj8 100015 miles. problems started with a coolant leak .the octopus hose. left the car parked for a week while getting hose. then the car would not start just kept turning over. the fuel pump had gone, so I replaced that. now I have fuel pressure but still not firing. changed spark plugs as they were dirty from turning over and not starting. I have a weak spark. it still will not start. there are no codes coming up so I do not know where to go next. any thoughts would be helpful thanks jrb53
Merry Christmas to all

 

Hi jrb,

Sorry to hear about your starting issues. Probably the number one cause of starting issues on a Jag is a weak battery. Since the car sat for a week, it could be that your battery was depleted enough to cause problems. If the voltage falls much below 11V while cranking, the ECM will not trigger the ignition to fire.

Have you tried jump starting the car with another vehicle? If you do, allow the battery in your wife's car to charge up for about 10 minutes with the jumping vehicle's engine running. For some reason, this seems to help. Jags don't seem to always respond to a jump start unless their own battery is charged above a certain threshold.

Other possible causes of weak spark are the ignition coil relay or corrosion in its socket. It's mounted in a row of relays on the right side of the engine bay and is the fourth relay from the left (as viewed from the driver's seat). You could try swapping it with the A/C clutch relay, which is the one on the far left end of that row.

Corrosion on ground points and battery power connections can cause problems - it might be worth cleaning the Engine Management System ground point in the center of the bulkhead/firewall and the false bulkhead battery power connection (disconnect the battery negative and positive cables before working on the false bulkhead connection).

Thinking of your coolant leak, it is possible that one or more electrical connectors in the engine bay were contaminated. It might be worth flushing all the connectors you can access with zero-residue electrical contact cleaner spray, allowing them to dry, then reconnecting them.

Hopefully others will have more ideas.

Cheers,

Don

 

Start with the battery, I let mine sit for 3 weeks while I did the timing chain job, and the battery was completely gone. I'd suggest jumping it and replacing with a Duralast GOLD battery. They run about $180

 

Thank you for your fast response Don .I will be checking everything you suggested on Saturday. I had put the battery on a charge the day before but I will check that again
Merry Christmas jrb

 

Merry Christmas to you and yours, jrb!

Cheers,

Don

 

Cylinder wash is something else to consider.

 

thanks Don B for the advice .switched over Ignition coil relay and lo and behold the car started. then I went about cleaning all electrical plugs. now I can get on with changing the Octopus hose . thanks to Jaguar Forum members yet again I am back on the road jrb53