Runs rich and dies on startup

[crackajack]

This is an intermediate problem that i have with m wifes explorer. Its an 03' Explorer Xlt 4X4, its got the 4.0l Flex fuel v6, very stock. My problem mostly ocurs when it is above 60 F outside. What happens is i start it and if i goto move it within o say 1-2 minutes then it bogs down and dies. After i start it right after it does this then it barrels out black smoke like your rommpin on a diesel. A lot of the time like last summer it would take 2-3 minutes of cranking to get any response out of the engine. I have been told that i have a bad o2 sensor but, the cel light isnt on, and that doesnt explain the endless cranking to get it started in hot weather. Any ideas?

Dont know if this has anything to do with is but i run 5-20w royal purple oil, and the oil is starting to get a little on the used side. its also got 60k on it.


Thanks

 

[Blee1099]

Check the Mass air flow sensor.. It may be unplugged or possibly dirty..

 

[BrooklynBay]

It might be the engine coolant temperature sensor, or the fuel pressure regulator. Check your fuel pressure. Here is a diagnostic chart for the ECT:

 

[JDraper]

I'd also lean towards a bad fuel pressure regulator. It needs to be checked in two ways. First is the pressure to the fuel rail, and the second is to pull the vacuum tube off it to see if there is fuel present in the vacuum tube. If there is, the diaphragm (dang I've typed that word a LOT in the last two days )is damaged and the regulator needs to be replaced.

 

[Lazzman]

If it is the fuel pressure regulator, where can you buy a replacement for a reasonable price. Ford wants like $560 for a new regulator, that includes the baided lines also.

Does Napa sell one?

Also if the the vacum tube does not have fuel present could the regulator still be bad? What is the procedure for using the fuel pressure gauge?

 

[JDraper]

If it is the fuel pressure regulator, where can you buy a replacement for a reasonable price. Ford wants like $560 for a new regulator, that includes the baided lines also.

Does Napa sell one?

Also if the the vacum tube does not have fuel present could the regulator still be bad? What is the procedure for using the fuel pressure gauge?

Napa on-line shows two choices for a fuel regulator for your truck. One at $79 and one at $132. FPR can be bad with no fuel present in the vacuum tube, that's where reading the pressure on the schrader valve on the fuel rail comes in.

 

[BrooklynBay]

http://www.explorerforum.com/forums/showthread.php?t=142801
http://www.explorerforum.com/forums/showthread.php?t=170334

 

[Lazzman]

Thanks Brooklyn.

What is the fuel pressure for a 1998 sohc motor at idle, Vacum line connected?

JD if the FPR was bad would the pressure be lower or higher than normal?

 

[JDraper]

It could be either. Depends upon how it was damaged.