Hi, My name is Derek and I have just got a very nice jag
Its the 3.2 xj6 on a p plate
It seems to start ok and run fine but if I park it when hot its pot
luck wether it will start or not
sounds like vapour lock to me? (this worked on my Ser III XJ so I
guess it’s worth a try) Put the tranny it in anything but P or N and
turn the ignition key as if you were starting it. The fuel pump will
run but the engine won’t crank. Fresh (cold) fuel will circulate if
you do this for awhile (say 15 secs or so). Then try starting it and
see what happens.
In reply to a message from stagcar sent Sun 30 Apr 2006:
when you crank it and it wont start do you smell gas? if you dont
smell gas its most likely a fueling issue. repl the fuel pump relay
in the trunk under the floor. if you do smell gas its a spark
issue. pajtas–
jaguarjoe 54 XK 120 rdstr 1961 MKIX 94 XJ6
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In reply to a message from stagcar sent Sun 30 Apr 2006:
Derek,
Had a similar issue on an AJ6 engine - I guess your 3.2 is
the same mechanically. Found that, when hot, the fuel system
was not maintaining the ‘hold pressure’ in the fuel rail
when the engine was shut down, ready to facilitate the next
start. That usually is attributable to a faulty fuel
pressure regulator or a defective non-return valve in the
outlet from the fuel pump, either of which will allow the
fuel to return to / drain back to the tank.
The rapid loss of fuel pressure in the fuel rail (mine
dropped from 40 + psi to zero in a few seconds) coupled with
the increasing heat in the engine when it is first shut
down, causes a sort of ‘vapour lock’ when the fuel ‘boils’.
You can determine if that is the case on your car by
employing the ‘key cycling trick’. When you anticipate a
hot-start problem, turn the ignition ON-OFF-ON five or six
times in rapid succession WITHOUT engaging the starter until
doing so immediately after the final ‘ON’.
That procedure takes advantage of the half-second priming
burst from the fuel pump that occurs every time you turn on
the ignition, and multiple priming bursts will generate
enough pressure in the fuel rail (if you are quick!) to
start the engine, which will then continue to run OK.
If that procedure cures the problem, you need to get the
fuel pressure checked to determine which component (the
regulator or the pump) is faulty. If you need the method,
let me know and I will e-mail it off list.–
The original message included these comments:
Its the 3.2 xj6 on a p plate
It seems to start ok and run fine but if I park it when hot its pot
luck wether it will start or not
It seems to turn over fine but will not fire atall
If you then leave it for about an hour it will start fine and run
for hours with no problem
In reply to a message from stagcar sent Sun 30 Apr 2006:
There is a TSB for the X300’s concerning the fuel tank pressure
control valve allowing the tank to overpressurize when running.
When you restart before the pressure has had a chance to diminish,
the additional pressure actually floods the engine at start up by
allowing too much fuel to exit the injector during its open pulse.
If you know where it is, test the valve by seeing if it will hold
vacuum, otherwise, remind your technician about the TSB.–
The original message included these comments:
It seems to start ok and run fine but if I park it when hot its pot
luck wether it will start or not
It seems to turn over fine but will not fire atall
If you then leave it for about an hour it will start fine and run
for hours with no problem