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fuel pressure regulator 2000 5.0

crunchie_frog

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I checked my fuel pressure and it is ~68 psi at all times. I checked vacuum at the regulator and it is okay. When I remove vacuum from the regulator, the fuel pressure does not change. My Haynes manual says fuel pressure should be 35 to 40 psi at idle and pressure should increase as vacuum is removed. According to Haynes, I either have a bad regulator or my return line is plugged.

Has anyone experienced this before and is so, what did you do?

thanks,
 


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snoranger

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I checked my fuel pressure and it is ~68 psi at all times. I checked vacuum at the regulator and it is okay. When I remove vacuum from the regulator, the fuel pressure does not change. My Haynes manual says fuel pressure should be 35 to 40 psi at idle and pressure should increase as vacuum is removed. According to Haynes, I either have a bad regulator or my return line is plugged.

Has anyone experienced this before and is so, what did you do?

thanks,

Your fuel pressure is fine.

The pressure regulator is inside the fuel tank, there is no vacuum to it.

Haynes manuals dont always know what they are talking about... That info is correct for a return style fuel system, not your newer returnless fuel system.
 




crunchie_frog

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Thanks,

I also have a 2000 5.0 mountaineer and I checked it and it is the same confirming everything is okay. There is something behind the intake manifold that has vacuum connection to it that is in the same spot as Haynes shows the regulator, was that just left on during manufacture. Same on both vehicles.
 




snoranger

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Thats a fuel rail pulse dampener.
 




kdspapa

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What does the "fuel rail pulse dampener" do exactly! I have some long crank times on my 99 Mountaineer 5.0 that I'm trying to solve.
 




snoranger

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It dampens the fuel pulses (drops and spikes in pressure) in the fuel rails created by the injectors pulsing. Thats not your problem.
 




kdspapa

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Thanks! I purchased an Actron fuel pressure gauge today and hope to find the time tomorrow to test my truck. Except those who had faulty fuel pumps, I haven't read any threads yet were someone has solved this problem. Maybe once they figure it out they forget to post their findings or I just haven't stumbled across it yet. Either way, thanks for your response!

I guess long crank times could be any number of problems. This leads me to also ask what role the fuel evaporation system could play in this? Someone told me to check this system out but it seems odd to me, but what do I know!
 




kdspapa

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Fuel Pressure Regulator/Dampener

My Chilton manual shows the fuel pressure regulator on the fuel rail to the rear of the engine and so does the Ford.com website. The Ford website also shows the fuel dampener in the same spot with the same part number. Ford.com doesn't show a regulator in the fuel tank. What's up with that? Can the dampener and regulator be combined into one unit? The fuel pressure regulator shows the part number change from 9C968 to 9F775 which, as I stated, is the same number they are using for the dampener. Also, the part O'Reilly sells as the fuel pressure regulator looks just like the part on my fuel rail.

Thanks for any help at clearing this up!

1999 Mercury Mountaineer 5.0L AWD
 




snoranger

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If you only have 1 fuel line attached to the rails from the tank, you have a returnless fuel sytem. In the returnless fuel system there is no regulator on the rails, its in the tank.
'98 was the 1st year of the returnless fuel system. You may have a return system if its an early build truck, I dont know exactly when they changed over. Look at your fuel line (or lines) going up to the rail... is there 1 or 2?


Read the first post in this thread.

http://www.explorerforum.com/forums/showthread.php?t=364540
 




kdspapa

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I just went out to verify what I thought I knew. I have two fuel lines. I put a fuel pressure gauge on the schrader valve earlier today and it eventually got up to 65 psi.

I posted to a different thread yesterday.
Here it is:
I just put my new Actron fuel pressure gauge on my 99 Mountaineer 5.0 and the first key on only showed around 20lbs. Second key on the gauge jumped up to 50lbs. Third key on gauge jumped up to 64lbs and that is where it stayed during engine idle (900 rpm). Reved the engine up to 3000 rpm with no change in fuel pressure. Stomped on the gas with just a little fluctuation in pressure but settled back to 64 lbs. Turned the key off and watched gauge for over 5 minutes and no drop in pressure.

I repeated the key on test. This time on the first try the pressure jumped up to 50 lbs. Second key on 64 lbs.

Redid key on test. First key on pressure jumped to 60 lbs.

I'm thinking my gauge needs to be broke in or I had junk in the fuel. I'm going to redo the test tomorrow to see what happens.

UPDATE

Next Day: Same results as before! Pressure starts low at first "key on" but after running this "key on" test several times the pressure will eventually jump right up to 60 psi on first "key on".

Is this a sign of a faulty fuel regulator or pump or both?

--------------------------------------------------------------------------------
This is why I'm looking at my fuel regulator!
 




snoranger

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Your '99 has 2 fuel lines running up from the frame to the fuel rails? Out of curiosity, whats the build date on the door jam sticker?
 




2000StreetRod

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Ford Explorer Ranger Fuel pressure test procedure

. . . I just put my new Actron fuel pressure gauge on my 99 Mountaineer 5.0 and the first key on only showed around 20lbs. Second key on the gauge jumped up to 50lbs. Third key on gauge jumped up to 64lbs and that is where it stayed during engine idle (900 rpm). Reved the engine up to 3000 rpm with no change in fuel pressure. Stomped on the gas with just a little fluctuation in pressure but settled back to 64 lbs. Turned the key off and watched gauge for over 5 minutes and no drop in pressure. . .

For a return fuel system the vacuum regulates the fuel pressure. No vacuum gives max fuel pressure. Max vacuum (idle) gives minimum fuel pressure. Cycling the ignition key eventually results in max fuel pressure since the engine is not running and there is no vacuum. 64 psi is high for engine idling assuming that you really do have a return fuel system which surprises me for a 1999 model. You may have a broken/disconnected vacuum hose to the fuel pressure regulator (FPR) or the vacuum diapragm may be ruptured. I suggest that you measure the fuel pressure with the engine idling and then disconnect the vacuum line to the FPR. There should be a significant increase in fuel pressure. See Ford Explorer Ranger Fuel pressure test procedure
 




kdspapa

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Guys, I think I made a novice mistake! When you asked me how many fuel lines I had running to my fuel rails I think I included a line that isn't a fuel line. I was looking at night under the truck using a flashlight. Today looking in the engine compartment, I just see one braided line on the driver's side going to the fuel rail. Should I be looking in a different place?

On the driver's door the tag has the date: Nov. 1998

Getting a closer look at the part on the fuel rail I now agree that it is the damper because it doesn't look like it bolts on as the rail mount fuel regulators I see online do. Another novice mistake. How is the damper attach. It doesn't look like it's removable.

I had 18 lbs of vacuum at the regulator (damper) vacuum hose and removing the vacuum hose at idle did nothing to the fuel pressure or engine idle. When I put the vacuum pump on the part at idle I could only pump vacuum up to 25 lbs (it held vacuum) which also did nothing to the idle or fuel pressure. I do hear the fuel pump running when the key is turned on but only for a short second. How long should it run? I changed the fuel filter two months ago and yesterday I swapped the horn relay with the pump relay with no change. I'll time the pump running time in the morning at first key on and post my results.

Except for long crank times (usually ten seconds) the truck runs great! I don't smell any gas.
Is it time to cut the access door in the rear floor and pull the pump/regulator. Are there any other tests I can do? Is the fuel pump and regulator one unit? It has to be the regulator but I'm somewhat of a novice. Motorcraft fuel pump and sender assy at Ford.com = $192.88 ouch! Any better options? Is there anything else I will need to purchase?

Just read an article from Carter Fuel Systems about electrical drop testing and the article makes a good arguement for dropping a fuel tank when installing a new fuel pump for cleaning.

Here is the link: http://www.carterfueldelivery.com/fuelpumps/_pdfs/support/TEC1620.pdf
 




2000StreetRod

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fuel filter replacement?

From your posts it appears that the only fuel pressure problem you have is it is slow to build up the normal pressure. If you cycle the ignition key two times and the engine starts immediately on the third cycle that pretty much confirms your slow pressurization. Have you replaced the fuel filter? It may be clogged.
 




kdspapa

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Yes I changing the fuel filter was the first thing I did. This morning I put the fuel pressure gauge on and had my daughter turn the key on while I listened for the fuel pump to run. It run for a short second. When she turned the key off and waited a few seconds then turned it back on the pump would run again for a short second. We did this a few more times and the pump ran each time for a short second. When I checked the fuel pressure gauge, I noticed that this time the pressure dropped pretty quickly. It didn't do this before. I checked the gauge connection and couldn't find any leaks. If the fuel pump is only designed to run a short second at key on and not designed to run up to a certain pressure, Then I am concluding that the fuel pump check valve is working intermittently. Once started the truck runs great. The problem is sometimes when it sits for a while, it looses its fuel pressure.

I've read that the check valve is in the pump so I need to find a complete replacement pump assy. Anyone running a Carter fuel pump or heard anything about them. Rockauto sells them and reading their website, they sound like it would be a good replacement. Any suggestions would be appreciated!

Guys! Thanks again for all your feedback. It really helps!
 




kdspapa

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Followup!

I purchased a Delphi fuel pump assy from Amazon for around $200 and, while I was waiting for delivery, I cut out an access hole in the rear seat floor. Everything went well! I used some stove-pipe metal as it was really flexible. I doubled it up after forming it to the floor and used some aluminum flat bar to hold it down with self-tapping screws. My Mountaineer starts-up great!

I originally thought I would get the Motorcraft fuel pump from the Ford Stealership as it was priced at just under $200 on Fordparts.com. When I inquired about it at my local stealership, they told me fuel pumps sell for around $500. Gasp! Crooks! I read several posts where some of you purchased Delphi so that's the way I went too.

I apoligize for my rookie mistakes when some of you asked me questions. I love this forum as it's helped me immensely to complete many repairs on my truck. Thanks again for all your help!

Looks like I'll be tackling the brake system next.

KDspapa
 




murf65

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What does the "fuel rail pulse dampener" do exactly! I have some long crank times on my 99 Mountaineer 5.0 that I'm trying to solve.
I have a 2000 explorer with a fuel dampener. Engine starts fine when its cold. after getting hot, shut off for 1 to 2 hours, long crank time before it starts.
Dampener leaking fuel to the vacuum port after engine is shut off, flooding the engine.
 




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