Support the Airforce with a little help...

[bigslow]

I'm a staff sargeant in the USAF and I have had a problem with my X stalling since about 3 months after I bought it. I thought I had it resolved as I did some sensor cleaning and swapping. I have replaced the IAC, and the EGR pressure sensor. I have cleaned the MAF, I have checked for vaccuum leaks and put in a new PCV valve. I have sea foamed it a few times and cleaned the throttle body. I have the following codes, P0171 and P0174. Which means both banks are running lean. So I don't think it is the 02 sensors.

I pulled my EGR valve off the other day but I don't have a vaccuum tester. I also pulled the EVR solenoid to take a look at it. Problem is, I think my Chilton manual has a mis-print on how to check the EVR solenoid. Should I be able to blow air thru it if there is no 12VDC power supplied to it?

I also read a thread talking about the EVR solenoid and it said it should have little or no vacuum applied at idle. I pulled the vacuum line going to the EGR while idling and there is a bit of vacuum. I thought this was it at first until I was driving home from work today.

My truck totally crapped out on me in the middle of the road. I threw her into park and turned it over, she started up and died again. I decided to check something and disconnect the vaccum line to the EGR and then try to start it up. No luck, it did the same thing. After about 10 minutes of just waiting my truck fired up and got me about 100 yards from my house and then died again. Same symptoms.

This usually occurs when I have been driving at higher speed for awhile then I come to a stop. When I pull away from the stop at around 20 mph it hesitates and then the idle drops off to about 300 rpm. Sometimes she will rev back up and take off, other times she just dies on me.

I am thinking it may be the fuel pressure regulator, but I don't really feel like blowing 70 bucks on a part when I don't know it is bad. Any suggestions would help, I have been doing a good bit of research here, all of which has been helpful but I haven't been able to locate my problem.

 

[mrd]

I am thinking it may be the fuel pressure regulator

I was told you can tell if the regulator is going bad by pulling the vacuum line off it and checking for any fuel in the line - tap it or whatever. I did this and no fuel came out of the line, but looking inside the end of the line it appeared a bit wet. I replaced it and it solved my problem of an unsteady idle.

I also replaced my fuel pump recently - at a rest stop during a long trip, I heard the tell-tale buzzing noise coming from the gas tank, and noticed weaker throttle response. I've read of someone with a bad pump with similar symptoms as you, though I believe they said it was driving very weakly (wouldn't go over 25mph) for a bit before it completely went.

BTW, I'm a PFC in the Army Good luck!

 

[bigslow]

HUAA!

Thanks for the information. I do remeber hearing about disconnecting the vac line, but I forgot all about that. But I think from what it sounds like I'm going to have to change my fuel pump. Going to do a little reading on that then head to the auto hobby shop on base.

I will let you know if it all works out.

 

[bigslow]

Ok went and bought a fuel pressure test gauge and hooked it up. I am running at about 30 PSI at the rail which is just a little low. While I had the gauge hooked up I pulled the vac line on the fuel pressure regulator and my fuel pressure remained the same.

I hooked the line back up and a few seconds later I got my hesitation problem and fuel pressure took a hard drop. I think it is the FPR but I want to be sure.

My Chilton manual says in chapter 5-6 figure 12 of fuel pressure test chart down at A5, "disconnect the fuel return line." "Is fuel being returned during low pressure condition?"

I think I know how to test this, but is 5 PSI out of tolerance really considered low?

I think I'm gonna go play with her a little more and see if she doesn't give me a better clue what is going on.

 

[Katmandu]

I'm a staff sargeant in the USAF and I have had a problem with my X stalling since about 3 months after I bought it.

I am thinking it may be the fuel pressure regulator, but I don't really feel like blowing 70 bucks on a part when I don't know it is bad. Any suggestions would help, I have been doing a good bit of research here, all of which has been helpful but I haven't been able to locate my problem.

Welcome aboard Sarge!

BTW, I am a "recently" (2 years ago) USAF Retired MSgt. Did my 20 and hung it up. REALLY do MISS the Force.

Anyways....... You're way off base on the Fuel Pressure Regulator thing. They rarely go bad nowadays.

Your issue is MOST LIKELY bad intake "O"-Rings. These O-Rings sit between the upper/lower intake. Th is a VERY COMMON RECALL on the 4.0 SOHC engine.

The Recall is Campaign # 00M12.

Check out this thread......

http://www.explorerforum.com/forums/showthread.php?t=61152&page=1&pp=20

STAY BLUE!!

 

[bigslow]

I have read about this problem but I have a 96 4.0 and it has the OHV push rod. Is it possible that this could be the problem still?

How would this affect the fuel pressure at the rail? Because I had a drop in pressure when I was testing it and it started to stumble like it does.

I still haven't gotten it fixed, but I'm going to the used parts place after work today to get a new FPR. If that doesn't fix it I guess I will have to check into intake O-rings.

Thanks for the input though.

 

[Katmandu]

Probably not then.

I would have to say the fuel pump is going out OR your fuel filter is plugged up.

Replace the filter and see what happens.

I bet it will still turn out to be the fuel pump though.

 

[bigslow]

well I used a bit of time at work and ran some test on my buddies FPR on his explorer. It seems that when you disconnect the vac line the pressure on the rail should jump up about 10 PSI. Mine doesn't change at all, so I went out and bought a new FPR. I will let you all know if this solves the problem.

 

[bigslow]

Well I just hung $90 worth of parts on my truck and I guess I will be changing the fuel pump after next paycheck. I sure love my explorer, I can't wait to pay her off next month so I can sell her...