QuestionMy 2001 S500 won't start if it is hot. Cranks very quickly, all dash lights come on. Recent problem, only last week. Starts perfectly if you wait about 2 hours. And if you try to start right after turning it off, no problem, but 5 minutes to 2 hours, nothing. Runs perfect once started. Not overheating, no other identified problems. Good oil pressure, and all dash lights, etc. come on with key. 102,000 miles.
AnswerRon,
Have you changed anything with the vehicle, service, repair, have you changed fuel providers or fuel octane rating? When the tank gets down to 1/8, I would get some Techron additive in the black bottle and add that to the tank then fill up with the manufacturer recommended octane fuel. Make sure that your fuel cap ratchets or is on tight.
I would also change the air cleaner element, if it has not been serviced recently.
The fuel pump charge the fuel lines and fuel rail just prior to startup.
If the control valve is leaking then the pressure drops and you have places for vapor bubbles to form. These non liquid areas become over heated and vapor lock can occur.
Also, if the injector are not kept very clean, The orfice seat and valve can leak down. The leaking injector can cause a similar fuel delivery problem.
A way to help determine if this is a fuel supply or electrical problem is to use a little starting fluid. You will need to remove the air cleaner cover and have some one try to start the vehicle during one of the no start period, As soon as it come up if possible. While they crank over the engine. Spray a little starting fluid into the intake.
If it is electrical the vehicle will not attempt to start at all. If it is fuel related, it will try to run for a couple of seconds and quit, indicating that the engine is running on the starting fluid only.
You don not want to use this starting fluid too often, as it tend to wash of cylinder wall lubrication.
Good Luck and let me know what you find out.
Rob
