Hi everyone I have a 09 ranger 2.3 that has been giving me a headache lately. Starts great in the morning and when getting off work but if I make a gas stop or go to the store it is hard to start when hot but not all the time. About 2 weeks before this started I replaced the fuel pump due to the original one being very noisey. 2 weeks later she started giving me problems. Fuel pressure on start up is 60psi. When i shut it off it goes down to 0 within a few seconds. I think this is normal for this type of fuel system in these? I decided to do a tune up including plugs fuel filter air filter aswell as cleaning the MAF sensor. This helped for a couple days but ended up coming back. I have no codes at this time.

 

Welcome to the forum

No not normal, fuel pressure should hold above say 25psi for MONTHS and MONTHS
Yes key on pressure should be 35-45 psi, running pressure 50-60psi

The fuel pump assemble has two parts that cause the system to hold pressure
The fuel pump itself has a Check Valve inside, a backflow preventer
There is also a Fuel pressure regulator(FPR), its a round piece about half have up the assembly
One of these is not working on the new assembly

The fuel filter has 3 ports
IN from pump
OUT to engine
OUT to FPR in the tank

The pump can provide over 90psi pressure
So the FPR is needed to give the system a stable pressure at idle and then at full load pulling a big trailer, lol

Does new assembly look like this: https://www.partsgeek.com/assets/rep...50-1140833.jpg

You can see the pump and the FPR(round part)

This may not be the problem, but it still should hold pressure, and if cold start is OK then this issue would effect warm start less

Try cycling key on and off a few times before starting just to see if it helps

Could be CHT(cylinder head temp) sensor
These were a know issue on the 2.3l Duratecs, not hard to change, its located between cylinder 3 and 4 spark plug boots, need a very deep socket to slide down over the connector to remove this sensor

Looks like this one: https://www.partsgeek.com/assets/pro...5-6GHFSJ9L.jpg

When you shut off the engine, all coolant and air circulation stops of course, the CHT sensor maybe going bad and showing OVERHEATED when you turn key back on, so its not allowing re-start until engine cools off a bit
Just a guess

 

Yes pump currently in is Delphi DFG0883. That’s what I was thinking back flow valve was bleeding off but I did see some guys that also had them bleed off but still started fine. I’ve been having him prime fuel pump every time he starts it last week. New pump is warrantied and will also check temp sensor. I will let you know what I find tomorrow

 

I had that same issue with my 1995 Honda Accord. It ended up being the ECM/ECU computer.module. I originally had changed the fuel pump and regulator. The ECM was bad. Easy fix and affordable. Costed me $150 for a rebuilt ECM. Took 10 minutes to repair. 4 10mm bolts and 2 wire harness had to unplug. My ECM was front passenger side under dash on floor. Hardest part was pulling the carpet back to get to the ECM/ECU on the floor board. This video below was a charm to me.

https://youtu.be/Vg0Qs--jP-M