Hard starting in the cold 4.0l v6

[fordranger?]

K I will try that I mean I can just get vacum caps to from my local auto parts store

 

[fordranger?]

Running fuel pressure this is at idle

 

[Uncle Gump]

Thats not enough...

You want closer to 40 psi.

So when cold... the engine wants a richer fuel mixture... the ECM runs open loop and cold engine fuel strategy. Until it warms up... then the ECM should be in closed loop and base fuel delivery off demands. With 25 psi of fuel pressure you're trying to start the engine lean. Injector pulse width will deliver more fuel at 40 psi then it would at 25 psi.

Looks like you have either a weak fuel pump... or a bad fuel pressure regulator.

When is the last time it had a fuel filter?

 

[Curious Hound]

I was thinking 35psi minimum. 40 would be better. 27 - not so good.

 

[fordranger?]

So I put new fuel filter in it like 2 weeks ago and have ran it for like an hour I drove it today it had 35 when I built up pressure then it bled back to the tank is my guess then it went to 25 when I started it I don't know probably a fuel pump I can hear it run and it's pretty loud to like I can hear it from the cabin of the truck so it probably needs to be changed and the regulator is probably screwed. someone said there's a chek value on the pump???

 

[Uncle Gump]

While running... pull the vacuum line from the fuel pressure regulator. The fuel pressure should increase with the absence of vacuum. Same as you going to WOT. The regulator does that to increase fuel pressure for the increased demands.

I wouldn't swear to a check valve being being on a fuel system with a return line. That wouldn't effect running fuel pressure... just when you shut it off.

 

[fordranger?]

Weres that............

 

[fordranger?]

Found it on the fuel rail by the coil pack I'll try that tom signing off for the night boys see yall tomorrow

 

[fordranger?]

Is this the regulator

 

[fordranger?]

Hey yall is this were the vacum line from the fuel pressure regulator gose to the trottle body rats chewed it off??

 

[fordranger?]

I was thinking 35psi minimum. 40 would be better. 27 - not so good.

 

[Curious Hound]

In your first picture, you circled a screw with a nut on it.

I don't have a 4.0l. So I can't take a picture for you. But that broken line needs to be fixed. There should be another similar piece nearby. Follow it from end to end and connect a new hose to replace the broken pieces

 

[fordranger?]

So where's the regulator

 

[Uncle Gump]

The regulator will be on the fuel rail that your injectors are connected to. Similar to this.

 

[Curious Hound]

So where's the regulator

Near the top of the engine, mounted on or near the fuel rail that feeds the injectors. It should look like this

Or this