Community Forums

mihiggie62 · 03-01-2015, 10:12 AM

My 2006 Bounder with a Ford V-10 seems to have a gas cap issue. After running for any length of time, I get a hissing noise from the gas cap like it's trying to get air or vent. Whan I open the cap it's like a vacuum. I bought a brand new cap that is supposed to be the one it takes from Ford, but it is still doing it. Do I have a problem and if so what is the fix.

mel s · 03-01-2015, 11:30 AM

Quote:

Originally Posted by mihiggie62

My 2006 Bounder with a Ford V-10 seems to have a gas cap issue. After running for any length of time, I get a hissing noise from the gas cap like it's trying to get air or vent. When I open the cap it's like a vacuum. I bought a brand new cap that is supposed to be the one it takes from Ford, but it is still doing it. Do I have a problem and if so what is the fix.

mihiggie62
That may be normal.
Are you having any engine issues?
If not I wouldn't worry about the gas cap.
Mel
'96 Safari

SarahW · 03-01-2015, 01:38 PM

You might call Ford to see if they think it's a problem. I know that a check engine light can be caused by a faulty gas cap. Let us know what you find out.

**CLIFFTALL** · 03-01-2015, 01:40 PM

I had two V10's and never heard of this. It might be a fuel line vent issue.

Waiter21 · 03-02-2015, 05:44 AM

This may be normal (it is on a car). The fuel system is not vented to atmosphere, but is a sealed closed system

If your getting a vacuum, this is a big problem as it will crush your fuel tank. Your gas cap has a one-way air valve built into it to prevent this from happening (It will let air go into the tank, but will not let air escape from the tank)

After your engine has run and entered closed loop, Your ECM will check to see if there is pressure in the fuel tank. if there isn't, it will turn on the CES light ( usually the filler cap was left off or the seal is bad.

If the ECM see's pressure, it will then open a purge valve that will vent the tank pressure to your intake manifold, via the charcoal canister.

The ECM then will verify that the purge has taken place by looking for a drop in tank pressure.

Pressure in the fuel tank is normal.

Here is a short writeup:

http://www.aa1car.com/library/evap_system.htm

John

C-Leigh Racing · 03-02-2015, 09:12 AM

I have a 99 F53 & it is doing the same thing, big vacuum when the gas cap is removed.

Some time back year or so, was having problems with the genset cutting off while going down the road in summer time, so suspecting that tank vacuum may be the problem & starving the genset of gas, I left the gas cap loose & the ol genset didnt give anymore problems with cutting off anymore.
I to bought a new gas cap & it did the same thing, still vacuum in the tank, so left it loose & no problem again.
When stopping to refuel, once the cap breaks the vacuum, the engine will speed up from a slower idle, like it started to get plenty of fuel.

One thing on the F53 chassis, that speed sensor in the rear end, they do go bad & for some reason when it is going out, it will affect engine performance. It will also make the ABS light glow.
On ours, the engine picked up a slight skip ever so often, replaced that sensor & all was well afterwards.
Neil

chboone · 03-02-2015, 11:00 PM

The fuel tank should not have pressure in it and only very slight vacuum, usually not enough to notice. If the tank is in a deep vacuum there is a problem with the vapor recovery (EVAP) system. Could be a pinched or plugged hose or the charcoal canister may be plugged or the purge valve that controls the tank pressure/vacuum has malfunctioned. The attached file shows the location of the canisters on an F53.

C-Leigh Racing · 03-03-2015, 09:33 AM

Quote:

Originally Posted by chboone

The fuel tank should not have pressure in it and only very slight vacuum, usually not enough to notice. If the tank is in a deep vacuum there is a problem with the vapor recovery (EVAP) system. Could be a pinched or plugged hose or the charcoal canister may be plugged or the purge valve that controls the tank pressure/vacuum has malfunctioned. The attached file shows the location of the canisters on an F53.

Thanks Chuck,
When I remove the gas cap, theres enough suction that if I was dressed up & had a tye on, if close enough it would suck the tye down into the tank.
Its strong enough, that I'm thinking like you've listed there must be a problem.

Just checked out that PDF you linked, looking at the pics, I've wondered what those big round things were for in the chassis, what job they did & now I know.
Thanks, Neil

mihiggie62 · 03-12-2015, 05:19 PM

Thanks to the diagram that Chuck sent I found the canisters underneath. Low and behold I found a hose that had gotten kinked. Straightened it out and problem solved, Once again thanks everyone for the help.

C-Leigh Racing · 03-13-2015, 10:08 AM

Quote:

Originally Posted by mihiggie62

Thanks to the diagram that Chuck sent I found the canisters underneath. Low and behold I found a hose that had gotten kinked. Straightened it out and problem solved, Once again thanks everyone for the help.

Give some details, where the kink you located was at. Might be others having that same problem, but it could be hid & cant find it.
Thanks, Neil

ARFFMAN · 03-13-2015, 04:41 PM

Were you having any engine problems before you found the kinked hoses? If so what was going on with your engine. I'm having problems with wide open throttle at 65+ mph. Engine chocking out unless I back down.

mihiggie62 · 03-14-2015, 09:43 AM

The kink was in a 6 inch use with what looks like a breather on it. It's on the back of I think tank 2(towards the rear) and was bent 90 degrees. How it got like that I have no idea since I am the 3rd owner. I was not having any issues with it as far as driving but have not taken it on any real long hauls before I fixed the hose. I know now that when I go to refuel and open the gas cap it acts like it should. A little suction but not enough to pull you in!