Starting issues after driving for a while

[fuglemonkey2004]

I need help im at a complete loss. About a month ago my 2006 liberty sport with the 3.7 in it started having an issue where when I get in it to go somewhere for the first time of the day or after several hours of sitting it fires right up. However if once I've driven it say 70 miles and its good and warm, after I shut it down to say go into Walmart and come back out it struggles to start. As in I try and it stumbles and dies. Try again same thing. But if I turn the key on,off,on,off,start it fires right up. Im thinking this is a fuel pressure issue but not sure. I've read some other posts on here about the same thing but couldn't really find anything that was a definite reason for this happening. Once she starts tho she runs damn good I will say that. Any advice would be helpful before I go and throw a new fuel pump in it which is what im thinking the problem maybe occurring from. Any help is greatfully appreciated. Thank

 

[lfhoward]

It is a fuel pressure thing. Mine did this many years ago, and replacing the fuel pump fixed it. The short term fix when the engine isn’t starting is to turn the key to “run” instead of start for 5 seconds to let the pump build up pressure, then start it.

My guess is the check valve in the pump is wearing out, so gas can flow backwards in the line towards the tank after you turn it off. This creates a vapor lock condition when the engine is hot. The pump itself always seemed fine and I never lacked for gas on the highway when I put my foot down.

 

[blackhawk]

Fuel regulator..... It can't hold the pressure. If Time to change the whole module or install only a new regulator. As you must pull down the tank is better to install the whole module.

 

[cas123]

It is a fuel pressure thing. Mine did this many years ago, and replacing the fuel pump fixed it. The short term fix when the engine isn’t starting is to turn the key to “run” instead of start for 5 seconds to let the pump build up pressure, then start it.

My guess is the check valve in the pump is wearing out, so gas can flow backwards in the line towards the tank after you turn it off. This creates a vapor lock condition when the engine is hot. The pump itself always seemed fine and I never lacked for gas on the highway when I put my foot down.

Mine was getting weird and I started doing this- turn to run and then buckle my seatbelt while it builds pressure then I start it. My son said I should have been doing this all along. Never knew.

 

[lfhoward]

Fuel regulator..... It can't hold the pressure. If Time to change the whole module or install only a new regulator. As you must pull down the tank is better to install the whole module.

I don't know if the regulator is part of the pump assembly. I know the fuel filter is.

 

[lfhoward]

Just following up. My Jeep has had the trouble starting when hot issue for a while now. A few years ago a fuel pump fixed it, but recently (the last year or so) it was back. Well, I recently needed to replace a fuel injector that went bad and I cleaned the carbon out of the throttle body while I was in there. And funny enough, the Jeep has started right up every time since, including when hot (when I would have expected it to have issues). I wonder how long the fuel injector was on its way out, and if that caused the no-start issue.

 

[fuglemonkey2004]

Just following up. My Jeep has had the trouble starting when hot issue for a while now. A few years ago a fuel pump fixed it, but recently (the last year or so) it was back. Well, I recently needed to replace a fuel injector that went bad and I cleaned the carbon out of the throttle body while I was in there. And funny enough, the Jeep has started right up every time since, including when hot (when I would have expected it to have issues). I wonder how long the fuel injector was on its way out, and if that caused the no-start issue.

I ended up replacing the fuses under the hood right before I started having this issue. Ended up putting the old ones back in and haven't had the issue since. I do have a bit of corrosion in there tho so im thinking that its interfering with the one for the injectors causing them not to actually get power