Hard starts after sitting all night

[Jakemari104]

Hello I have a 02 wrangler tj 4.0l, recently have been having a hard cold start after sitting for more than 8 hours, hard starts and idles rough for a few minutes and then clears out and will start and run good the rest of the day, fuel pressure is at 49psi while running and very slowly loses pressure once key is turned off, will drop down to 10 psi from 49 very slowly in about 4-5 hours with key off , anyone have any ideas what could be my problem, don’t want to start throwing parts and money at it and it not fix my problem thanks

 

[JP_in_STL]

Likely time for a fuel pump assembly. Something is bleeding pressure off when it sits. If you don't smell gas or see any drips then its not a bad line. So either an Injector (do you gain any oil) or its on the fuel pump end. Delphi or Bosch if you can find them. Mopar is no longer made. Depending on rust level, and tool collection, its a 2-3hr job. Tricky part is getting the locking ring on correctly. Prop the tank up on a couple blocks at the ends, so the center sags a bit, then try and install the pump assembly.

 

[Jakemari104]

Hello I have a 02 wrangler tj 4.0l, recently have been having a hard cold start after sitting for more than 8 hours, hard starts and idles rough for a few minutes and then clears out and will start and run good the rest of the day, fuel pressure is at 49psi while running and very slowly loses pressure once key is turned off, will drop down to 10 psi from 49 very slowly in about 4-5 hours with key off , anyone have any ideas what could be my problem, don’t want to start throwing parts and money at it and it not fix my problem tha

Likely time for a fuel pump assembly. Something is bleeding pressure off when it sits. If you don't smell gas or see any drips then its not a bad line. So either an Injector (do you gain any oil) or its on the fuel pump end. Delphi or Bosch if you can find them. Mopar is no longer made. Depending on rust level, and tool collection, its a 2-3hr job. Tricky part is getting the locking ring on correctly. Prop the tank up on a couple blocks at the ends, so the center sags a bit, then try and install the pump assembly.

Do u know what fuel pressure should be at with key off? Should it stay above 30 psi after shutdown within 5 minutes, kind of stuck between it being injectors and the fuel pump assembly

 

[LONGJP2]

Do u know what fuel pressure should be at with key off? Should it stay above 30 psi after shutdown within 5 minutes, kind of stuck between it being injectors and the fuel pump assembly

I believe there's a troubleshooting procedure in the FSM.

 

[macleanflood]

Should be 47 to 50 psi.

-Mac