Fuel pressure regulator and hard start when cold

[Pete71]

Hola,

I am about to get my 2004 4.0 XLT Explorer back. My daughter had it. Anyway, it has had a check engine light on for the last five years or so. When I had it checked it was the fuel pressure regulator. I've never changed it. Well now, when it is cold it will not start. Could this regulator be the problem or is it probably something else. The full problem description is it will not start when cold. If you wait a bit it will start and run fine. Very rarely it will lose power and sometimes die while warm. I really want to turn this into a fun off road vehicle (nothing extravagant) but need to work on making sure it is reliable first. Any ideas?

Gracias

 

[J_C]

We might need more info. What OBD2 (or Ford specific) code was set?

If there is a fuel pressure sensor it could read out of bounds but then it can't yet be determined if it's the sensor or the pressure is actually low, until you measure fuel pressure, and then, if pressure is low it could be the regulator, or the pump, or filter.

If it is cranking over good, it certainly could be a fuel pressure problem so again the codes should be pulled with a scan tool and check the fuel pressure, OR it could be some other problem. If the fuel pressure isn't low and no set codes seem related, then I'd want a scan tool showing realtime data, for not only when it won't start but also when it's running. Come to think of it, if it won't start cold then how do you ever getting it running again?

You really shouldn't leave the check engine light on long because then it fails to alert you of some new, more important problem that needs more immediate attention.

Low fuel pressure tends to manifest itself most when the engine is under load, if/when you get it running. If it's not conspicuously doing that, I'd wonder if you have a vac leak somewhere, but no need to speculate when you can measure the fuel pressure. Many auto parts stores have fuel pressure gauges as a free loaner tool (just put down a deposit on it).

 

[Pete71]

We might need more info. What OBD2 (or Ford specific) code was set?

If there is a fuel pressure sensor it could read out of bounds but then it can't yet be determined if it's the sensor or the pressure is actually low, until you measure fuel pressure, and then, if pressure is low it could be the regulator, or the pump, or filter.

If it is cranking over good, it certainly could be a fuel pressure problem so again the codes should be pulled with a scan tool and check the fuel pressure, OR it could be some other problem. If the fuel pressure isn't low and no set codes seem related, then I'd want a scan tool showing realtime data, for not only when it won't start but also when it's running. Come to think of it, if it won't start cold then how do you ever getting it running again?

You really shouldn't leave the check engine light on long because then it fails to alert you of some new, more important problem that needs more immediate attention.

Low fuel pressure tends to manifest itself most when the engine is under load, if/when you get it running. If it's not conspicuously doing that, I'd wonder if you have a vac leak somewhere, but no need to speculate when you can measure the fuel pressure. Many auto parts stores have fuel pressure gauges as a free loaner tool (just put down a deposit on it).

I will get the code read again and see exactly what it says. I have done it a couple of times but that was more than a few years ago.