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Gas in Vacuum lines

bdufpv

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February 15, 2014
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City, State
Phoenix Arizona
Year, Model & Trim Level
2002 Ford Explorer
i have a 2002 ford explorer with the 4.0 sohc. the check engine light came on with p0401 (erg valve) and later p0455 (Evaporative Emission system leak: large). i think they are related and i will get to what is probably causing them to trip.


my first attempt to fix it involved removing the egr valve, checked the valve and it was moving under vacuum, cleaned it and the tube into the throttle body. removed the negative battery cable but the code soon returned. i stopped there and started to work on the p0455.

for the p0455 i started by looking at the evap purge solenoid (in the engine compartment by the battery). when i removed the two larger hoses (one from the canister and the other goes to the intake) everything seemed normal. when i removed the electrical connection from the solenoid gas poured out. i have since removed the electrical connection multiple times and gas continues to flow out. the last time i removed it i saw gas pour out of the vacuum line as well. this was the first time i noticed this. i am thinking that the only way gas will come out of the electrical connection is through the vacuum line and not from the house from the canister or the hose to the intake.

i did some research and read that the fuel pressure relief valve could be the issue. i disconnected it and the vacuum line was dry. i then turned the ignition, but did not start the car, gas came out of the fuel pressure relief valve-which would have gone into the vacuum line if it was connected.

my thought is this is how gas is getting into my vacuum lines. is the fuel pressure relief valve what needs to be replaced, are there other tests i need to do, or is there something else that could be causing gas to get into the vacuum lines?



some more info...the gas mileage seems to have gone down 3-4 miles per gallon and when the explorer is parked in the garage there is a very strong gas odor (I'm assuming it is coming from the gas in the vacuum line to the evap purge solenoid, it is almost dripping!). also when the gas tank is only 1/4 full it will stall at stops and right turns. i have read of the pumps being the issue with this.

Thank you
Brian



this is a link to the fuel pressure relief valve
http://www.autozone.com/autozone/re...ageId=0996b43f802e3ddb&CJPID=3663046&cmpid=cj
 



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Fuel should not be going into the vacuum line. That means the regulator is bad. Replace.
 






fuel pressure damper

In 1999 when Ford switched from a return fuel system to a returnless fuel system the fuel pressure regulator mounted on the fuel rail was replaced with a fuel pressure damper. The fuel pressure regulator is located in the fuel tank. However, there is a diaphragm in the fuel pressure damper that is connected to a vacuum hose. The diaphragm can rupture and result in fuel leaking thru the diaphragm into the vacuum hose and being pulled into the intake manifold. If you have a vacuum pump the diaphragm is easily tested. Just connect the vacuum pump to the fuel pressure damper and see if it will hold vacuum. If it does the diaphragm is good. If not, replace the damper.
 






thanks for the responses. i hooked the fuel pressure damper to a vacuum. i can not pump the vacuum past 17 pounds without it dropping pressure AND i can see gas bubbling in the clear tube that the vacuum is hooked up to. it will drop to 16 pounds and it appears to be holding there (after about 5 minutes).

how many pounds should it be able to hold?
should gas come out of the fuel pressure damper at a high enough pressure?
does this identify the fuel pressure damper as the problem?

thanks again
brian
 






You should be able to pull it down near 30 inches vacuum. There is a tear or leak on the diaphragm of the damper. Time to replace.
 






I agree with FordFool2

You should be able to pull it down near 30 inches vacuum. There is a tear or leak on the diaphragm of the damper. Time to replace.

Vacuum with the engine at idle is typically 17 to 22 in-Hg. I just checked my original fuel pressure damper. It holds 25 in-Hg which is the maximum my hand pump can pull.
 






i have ordered a new fuel pressure damper from rock auto and i am waiting for its arrival. they had the best price i could find and it should be here in a couple of days.

i never checked the pressure at idle, i only checked it with the engine off.

2000StreetRod, was gas bubbling out of the fuel pressure damper when you had it up to 25 in-hg?

i will check the brand new one when it arrives and post the results with the engine off and at idle.
 






holding vacuum

. . . 2000StreetRod, was gas bubbling out of the fuel pressure damper when you had it up to 25 in-hg? . .

No. It was not connected to the fuel rail and I was holding it in my hand. Since it was holding vacuum (no leak) fuel would not have been coming out if it had been connected to the fuel rail. Holding vacuum means the diaphragm has no cracks.
 






the new fuel pressure damper arrived today. i hooked it up to the vacuum and it held 25 in hg while not installed on the fuel rail. once installed on the fuel rail it also held 25 in hg and there was no gas bubbling out of the vacuum pump tube. this is very different than the old one with the broken diaphragm, which only held 16 in hg and gas was bubbling out the vacuum tube. as further proof that the diaphragm was broken, when i removed the engine vacuum tube off the old fuel pressure damper to remove it from the fuel rail, a ton of gas drained out of the vacuum hose.

i will recheck the engine vacuum hoses that previously had gas in them in a couple of days to see if they have dried out. is there any thing else that i should do because there was gas in the vacuum lines?

thanks to everyone for their input. you guys were right from the beginning, i just wanted to ask a ton of questions and follow up with my results to hopefully help the next guy who has this issue.
 






Glad we could help and see that it's fixed. Thanks for sharing the results.
 






replacing the fuel pressure damper also solved the starting problem it was having. the car would start fine in the morning or after it sat for a long time, but if we did a quick trip it would turn over for 5-10 seconds before it would start. it has not don't it since the fuel pressure damper was replaced.

the AC is now also switching vent locations without a problem.
 






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