Hi All, Any help/advice appreciated, really pulling my hair out now!

From the Beginning! Jag had been stood for 3-4 months (not started) so decided to get her going for some trips away, went to the car, wouldn't open as my key fob battery had gone flat, so I used the key instead to open the car manually, alarm beeped until I put the key in the ignition which then cancelled it, tried to start but the cars battery was flat so put on a booster pack and everything started up fine as it should then after approx 3-5 seconds she just cut out (almost like it had stalled). The fuel was low but showing 28 miles range so should be more than enough to just start up and idle??

So I tried to restart the car only for it to just crank over but not fire, figured I may have either flooded her or the battery was still too weak? So I charged the battery up over night went back to her the next day and still wouldn't start even though battery showing good charge. I assumed she may be flooded so talk all the plugs out dried them off, foot right to the floor, she turns over and sounds like shes going to fire but doesn't happen!

Since then I have checked every relay and fuse (swapping and testing with the spare horn relay) to see if any faults there, just one fuse had blown a 25 amp one which I have replaced still wont start!

Took off the crank sensor which did look quite mucky and gave that a good clean with electrical contact cleaner, refitted still wont start.

Put a load extra fuel in, still wont start.

I then had some advice to try disconnecting the MAF which I did and after nearly a minute of cranking she fired up and ran very very poorly (rough, shaking excessively) unaided then after approx 1 min or less she cut out and would not restart!

Since then I have changed the fuel filter and checked that I have fuel at the fuel rail which I do, good pressure too it seams squirts when trying to crank.

Ive tried wiggling the gear lever in park as heard that can sometimes help start??

Spark plugs have spark and they arent very old and only done 1000 miles or so but they are quite black to be honest?? Would this make a difference?

Also on opening the door with just the key no remote fob the alarm no longer beeps until I put the key in, infact the alarm makes no sound at all now whether you lock or close the car?? Is this related, is it the immobilizer?

Any Help really appreciated!


Not sure what else to try now, I have fuel, air and spark it seems but no start!

 

I do not know much about XJR but does the key fod have a transponder in it for the immboilzer.then the dead battery in the fob would be next to change.

this is just an educated guess btw

 

Yeh I think it does as you have to have it coded to the car to work, not sure if that just effects the frequency though? I'll try that tomorrow see if makes any difference!

 

Did you fix this problem and if so how? I have the same problem with the car not starting.

 

if the revelations i have had recently are anything to go by i would check you have not got condensation on the ecu. it caused a huge problem for mine until i removed it and dried it out on the radiator. its in the drivers footwell in front of the door. just tyhinking its been very cold/wet lately so its worth a punt

 

Fixed! see "1996 XJR will not start" thread

 

Mine is actually on the passenger side footwell. Just an FYI for others.

 

Dan, that would be because you are in the US and the original poster is in the UK!