Lacking gas tank pressure
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Senior User
Joined: Jan 2004
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From: Wisconsin
Lacking gas tank pressure
Recently I purchased a code scanner and have been monitoring my '01' 3.0 4x4 to see if I could catch a code when the flashing o/d comes on. No luck on that yet but there is a readiness check that indicates there is a .020 leak in the gas tank pressure check. It seems a .020 leak won't set a code but a .040 one will. Does that sound right? Anyway, there is never a rush of air sound when I open the cap on the tank to fill-up. Seems like there should be. Anybody have any suggestions as to possible problems or what to check. The cap and filler neck appear to be OK (no damage and the seal appears to be intact) but maybe I'm missing something. There does not appear to be any gasoline leaks either. Thanks for any help.
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Joined: Jan 2005
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From: Englewood, CO
Unless it is very hot outside, then it probably won't rush air out. Being a closed system means that there is a vent line from the tank to the evap canister or carbon canister under the hood. This captures the fuel vapors to be purged after the engine is running. So unless it gets hot enough to build pressure in the tank faster than it can vent it thru the canister, there will not be a rush of air.
Mine goes thru all kinds of codes, but until it actually sets one is use the old "If it ain't broke don't fix it"...
Mine goes thru all kinds of codes, but until it actually sets one is use the old "If it ain't broke don't fix it"...
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Joined: Sep 2003
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I have a '98 Ranger and had an evap system code for a mass leak in the system. Found it to be the fuel tank pressure sensor on the top of the tank. It somehow broke a little above where it's attached to the tank. Pain to replace without removing tank. I just reattached it with a small piece of rigid tube and JB Welded it back together. No more codes.
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Senior User
Joined: Jan 2004
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From: Wisconsin
Thanks for the responses. I agree about if it ain't broke don't fix it. I'll wait until it gets warm and see if any pressure builds up. Truck engine runs fine but I was just curious about the lack of pressure and readiness test codes.
