hi
i have recently joined jec
i have 1974 xj12l just been put back on road after 27 years in storage
alls fine apart from when driven and reached running temp
switch car off will not restart until cooled down
any ideas to rectify
thanks
non starter when hot
Moderator:LJR
Re: non starter when hot
Hi Molly,
Welcome to the club, and especially the XJ 12 L Series 2. The same model as mine.
The problem you have is occasionally experienced by me. Over time you will become familiar with the various starting problems and learn to cope with them.
There are several aspects to this when both hot or cold. For the moment I'll address the when hot problem. Based on the shear mass of engine the under bonnet temperature seems excessive but this is normal and as a result expansion of fuel takes place. So when you come to start there is a mass of surplus fuel. To start I turn the key and at the same time give it some throttle, that usually works. If that doesn't work do not keep grinding away on the starter cos it won't start.
Ideally as you say, leave it for a while, however if that is not an option, push the throttle to wide open and hold it there and crank the engine. You will note that the cranking speed will increase and with a lot of black smoke burst into life.
Why, you might ask does this situation arise. Now, do you have a proper Jaguar workshop manual. If so, look for the fuel pump layout in the boot and work out the way the system works
you will see that there are two solenoid valves these ensure fuel returns to the correct fuel tank.
Early Series 2 had solenoids that both closed when the ignition was switched off, therefore no escape for expanding hot fuel so a flood situation occurred. The arrangement seems right and proper but did not accommodate this fuel expansion problem. The solution on later models was to replace the solenoids with ones that remained open when the ignition is switched off.
I've owned mine for about 40 years and periodically promised myself to get some later solenoids but never quite made it
So, as a start you need to establish which solenoids you have fitted
I hope that helps a little , come back if you need more on this subject
Oldtimer
Welcome to the club, and especially the XJ 12 L Series 2. The same model as mine.
The problem you have is occasionally experienced by me. Over time you will become familiar with the various starting problems and learn to cope with them.
There are several aspects to this when both hot or cold. For the moment I'll address the when hot problem. Based on the shear mass of engine the under bonnet temperature seems excessive but this is normal and as a result expansion of fuel takes place. So when you come to start there is a mass of surplus fuel. To start I turn the key and at the same time give it some throttle, that usually works. If that doesn't work do not keep grinding away on the starter cos it won't start.
Ideally as you say, leave it for a while, however if that is not an option, push the throttle to wide open and hold it there and crank the engine. You will note that the cranking speed will increase and with a lot of black smoke burst into life.
Why, you might ask does this situation arise. Now, do you have a proper Jaguar workshop manual. If so, look for the fuel pump layout in the boot and work out the way the system works
you will see that there are two solenoid valves these ensure fuel returns to the correct fuel tank.
Early Series 2 had solenoids that both closed when the ignition was switched off, therefore no escape for expanding hot fuel so a flood situation occurred. The arrangement seems right and proper but did not accommodate this fuel expansion problem. The solution on later models was to replace the solenoids with ones that remained open when the ignition is switched off.
I've owned mine for about 40 years and periodically promised myself to get some later solenoids but never quite made it
So, as a start you need to establish which solenoids you have fitted
I hope that helps a little , come back if you need more on this subject
Oldtimer
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