Rough start after warmup only.
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Joined: Dec 2009
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Rough start after warmup only.
99 F-150 5.4 motor starts great, runs great with no problems except for one thing that I cant figure out or anyone else I know. I have also had Ford run the diagnostics with no help to speak of.
I can always start the truck when cold with no problems. Once the truck is warmed up and has been running for awhile then there can be a issue. If I shut it off, and leave it sit for about 10 minutes or so, I have a terrible time restarting it as it just cuts out and sputters for a couple of minutes before it smooths out. Sometimes it wont smooth out until I keep retstarting it over and over and then it will smooth out and run great the rest of the time.
Weird thing is if I were to shut it off once warmed up and immediately restart it there would be no problem. Its only when I leave it sit for several minutes that there is a issue
Is this a leaky fuel injector thats draining into the cylinder and filling up thus flooding the motor? If so, how do I locate that fuel injector? If not, then I am stumped.
Please, can anyone help that has had a similar experience.
I can always start the truck when cold with no problems. Once the truck is warmed up and has been running for awhile then there can be a issue. If I shut it off, and leave it sit for about 10 minutes or so, I have a terrible time restarting it as it just cuts out and sputters for a couple of minutes before it smooths out. Sometimes it wont smooth out until I keep retstarting it over and over and then it will smooth out and run great the rest of the time.
Weird thing is if I were to shut it off once warmed up and immediately restart it there would be no problem. Its only when I leave it sit for several minutes that there is a issue
Is this a leaky fuel injector thats draining into the cylinder and filling up thus flooding the motor? If so, how do I locate that fuel injector? If not, then I am stumped.
Please, can anyone help that has had a similar experience.
Lead Driver
Joined: Sep 2006
Posts: 7,907
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First item I would check out is the fuel regulator for a leaking diaphram allowing raw gas into the intake through the vacuum line.
Next fuel pressure at shutdown for fast leak down of pressure.
A way to tell if it's excess fuel is to crank with the throttle wide open to see if it starts and clear much faster once started. The wide open throttle shuts the fuel injection off.
If yes, go looking for the cause of excess fuel as above.
Good luck.
Next fuel pressure at shutdown for fast leak down of pressure.
A way to tell if it's excess fuel is to crank with the throttle wide open to see if it starts and clear much faster once started. The wide open throttle shuts the fuel injection off.
If yes, go looking for the cause of excess fuel as above.
Good luck.
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