rough running problem

[monkeydude3]

Hello all

I have a 1994 explorer XL 4.0L OHV... manual trans.... she's running rough on the low end and I hear a popping/spitting sound out of the exhaust.... I checked the fuel pressure and it is 30psi... spec is 35-45 psi... could this be causing my trouble.... could the cause be the fuel pressure regulator? any ideas would be grand! thanks!!

GEORGE

 

[MrShorty]

It certainly could be the fuel pressure regulator. Try this:
1) Key on engine off, ground the fuel pump test lead in the self-test connector. This will activate the pump.
2) What is the pressure? Presumably it's the 30 psi you've indicated. In this low pressure state, can you hear fuel being returned to the tank (indicates that the FPR is allowing fuel through at too low of pressure)? If you can, I think that pretty much means the regulator is shot. If you can't, then there's something wrong on the pump side of the regulator that prevents pressure from building (clogged filter or line or weak pump).
3) If you start the engine, what does the pressure do?

 

[monkeydude3]

EXCELLENT idea mr. shorty... I will try that tomorrow, possibly... I have a crammed tight work schedule to work around which is why this problem is taking so long to get fixed, and I'm glad to hear that I am on the right track... do you have any places online that you would reccomend me to get a FPR from? As in a good price... the autozone by me can get it to me for $100.... thanks a ton!

GEORGE

 

[monkeydude3]

Also Mr. shorty... which tester lead would that be? Thank you !!!

 

[kdogg212001]

hey i also was told that ton my 94xlt it could be the fpr , my symptoms: while in park if i reved it i would get a gas smell, also sometimes while idling at a stop light i would get increase in rpms, idling at about 5 or 6hundred then jumping to about a 1k , does this sound like a fpr related issue??

 

[MrShorty]

Also Mr. shorty... which tester lead would that be? Thank you !!!

In the self-test connector, the fuel pumptest lead is the outermost lead on the short end of the connector. A good manual, or even Chiltons (see the vehicle repair guides fuel section at www.autozone.com), will have a diagram of the connector showing the fuel pump test lead.