Starting problems

[EriEvan]

I have a 1997 R reg XK8 with 103K on th clock. I've had the car 4 years and ever since I've had it there has been a problem when the car has reached normal running temperature and then has been left standing for between 0.5 and 1/3 hours. When I try to start the car it rarely fires first time and cranks over excessively. I generally switch off and try again when it will start although sometimes hesitantly. From cold there is no problem or if the car has been left standing for less than 0.5 hours.

The car has been back to the local Jaguar garage who say they can't find anything wrong and to an independant specialist who is also baffled. The water thermostat has been changed and all the solinoids but these changes have made no difference.

Anybody had a similar problem or any ideas of what else can be done.

[RMA37]

I've searched the forum for a thread covering starting problems and this is the only one that details exactly the fault my car has. I also note that the OP had no replies since posting in 2008.

My car is a 1997 XK8 Convertible 4.0 with only 31K on the clock. It has exactly the same problem as described by EriEvan, but when I remember, I put my foot on the accelerator when turning the key and it starts quicker. Does anyone here have an answer? Thanks

[Astromorg]

From the description it sounds like it maybe a fuel vapour lock in the line caused by heat soak from the hot engine while it's sitting there. Was that the thinking behind the new thermostat, I wonder? Or it might be a 'vacuum lock' caused by a fault in the fuel tank vent system. Next time it happens, open the fuel filler cap and see if there's a notable rush of air to the tank.

I would check that all the heat shielding, (if any) between engine/exhaust and the fuel lines is present and correct.
I'd check fuel pressure, either with a gauge on the schrader connector or with a scanner.
Check the operation of the fuel pressure regulator as follows (From JTIS)
Make sure the vehicle is in Park for vehicles with automatic transmission.
Apply the parking brake.
Place suitable absorbent material around the schrader valve to absorb any spillage when connecting the gauge set.
Remove the protective cap from the schrader valve.Depending on the design of the gauge set, there may be a drain valve and tube. Make sure this valve is closed, and the drain tube placed in a suitable container BEFORE connecting the gauge to the schrader valve.
Connect the gauge, using adaptors if required.
Remove the absorbent material and dispose of safely.
Disconnect and plug the vacuum hose from the pressure regulator. Start the engine and record the fuel pressure reading. As a guide, the fuel pressure should be approximately 3.0 bar (44.1 psi) with the regulator disconnected.
With the engine still running, reconnect the vacuum hose to the pressure regulator and record the reading.The pressure should drop to approximately 2.6 bar (38 psi) when the vacuum hose is reconnected.
Switch off the engine.

[RMA37]

Thank you for your reply and suggestions.

I did think it might be due to vaporisation and I'll check the fuel lines. I don't have the equipment to check pressures etc. Vacuum lock is interesting and I'll check that next time out, although I won't be using the car for the foreseeable future due to the present situation. Filled the tank yesterday after taking for a run and now laid up!

Hopefully we'll all be able to enjoy our cars for the summer. Take care everyone.

[alamn2]

Thank you for your reply and suggestions.

I did think it might be due to vaporisation and I'll check the fuel lines. I don't have the equipment to check pressures etc. Vacuum lock is interesting and I'll check that next time out, although I won't be using the car for the foreseeable future due to the present situation. Filled the tank yesterday after taking for a run and now laid up!

Hopefully we'll all be able to enjoy our cars for the summer. Take care everyone.

hi did you ever get a solution for this ?

i ahd this when the engine was hot and if i went to neutral then to reverse or drive would stall and not start until it cools. happened every time engine was hot

a replacement coolant temp sensor and its been 2 years not had the problem again