jeep wont start at times…mostly following driving, i will park, return 15 min to half hour later and wont start
That has two meanings
You turn the key, and nothing happens.
Or, you turn the key, the engine cranks over, but doesn’t fire up.
Thanks…here’s the symptoms:
I drive the jeep, 2006 wrangle Rubicon, manual transmission, 79K miles, for about 15-25 min - or longer. Following turning off the jeep for about 15min or more I return and the Jeep wont start, the engine turns over but wont start. Following cranking for a few min it will finally sputter and start. Thanks for the help I appreciate your help.
Carry a bottle of water in the Jeep.
The next time the engine won’t start, open the hood and pour the bottle of water over the fuel rail(s).
If the engine starts after doing this, the problem is vapor lock.
Dealt with this on my similar Jeep, it is especially bad on the 4.0L engines. They sell a heat shield kit for this problem, I am not sure as to how effective it would be though.
tks…what is the problem you mention??? what will the heat shield protect?
You want to have the fuel pump tested for residual fuel pressure.
Residual fuel pressure is the pressure that remains in the fuel system after a hot engine is turned off.
This pressure prevents vapor lock from occurring, so the hot engine can be restarted shortly after it’s turned off.
To prevent fuel percolation and aid hot- and cold-engine starting, fuel injection systems must maintain residual, or “rest,” pressure when the engine is off. All systems lose residual pressure over time. It’s just a question of how fast and how much before it’s a problem.
Since the entire supply side of the fuel system is normally pressurized, a loss of residual pressure could be caused by a leaking injector, pressure regulator or fuel pump check valve. Determining which involves isolating various parts of the fuel system, saving you the trouble of visually inspecting each component.
In my situation it was what Tester suggested (the “vapor lock” or “heat soak”) but it was also my fuel pump was going out. The heat shield I suggested is found all over. Here is a link to one on Quadratec. https://www.quadratec.com/products/17604_1031.htm?gclid=Cj0KCQiA48j9BRC-ARIsAMQu3WTJd16TBdIs8BOCXTUcMWyFvjJZiLf6d-zS3nsAljTiDhp04hj5-DAaAqAdEALw_wcB
tks for the info…
So are you telling me that that the fuel pump going out was the cause of the vapor lock??? tks for the help??
Tester…tks so much for all the useful info. You give some great starting points for troubleshooting.
Tester…Thank you for that reply…i just saw it. It make the most sense to me.
If lack of fuel or low fuel pressure are the cause of the non-start, the “key dance” is worth a try: turn key to Run (not all the way to Start) and the fuel pump should run for a few seconds. You may hear it. Turn it Off then right back to Run. Each time you are getting fuel and fuel pressure up to the engine. After a few of these steps, turn the key all the way to Start. Good luck!