Fuel Cap Leak..

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Drift

Member
Joined
May 6, 2013
Posts
6
Reaction score
0
Location
Tri-Cities, Washington
Raptor has check engine code for fuel cap leak. Displayed on dash for awhile but check engine light remains. I just ordered the PLX Kiwi WIFI broadcaster so I could attempt to clear code and have useful gauges close during sprited desert driving. Until that arrives was wondering if anyone has experiences or can shed some light on self service. If I remember right engine code from an Autozone check was P440 relevant to a fuel leak.

I could also have gouged a rubber fuel hose but I haven't seen any signs of issues from quick crawls under the truck so I think its the cap design leaking. Maybe some hybrid car jerk thought I had extra fuel to spare and tried to get at it.

Anyone else had this kinda issue?
 

Fred

FRF Supporting Member
Supporting Member
Joined
Sep 3, 2011
Posts
7,432
Reaction score
2,157
Location
Richmond, VA
do you smell any gas or see any on the ground or on the underside of the truck?
 

SVT_4X4

Full Access Member
Joined
May 3, 2012
Posts
516
Reaction score
258
Location
Linden, MI
The capless system has a seal on the flap that closes when you pull the nozzle out at the gas pump. Maybe that seal has failed and the fill tube will need to be replaced.
 
OP
OP
D

Drift

Member
Joined
May 6, 2013
Posts
6
Reaction score
0
Location
Tri-Cities, Washington
Fred, no, that indicator would have been better then a check engine light. I spent awhile under the truck with a full tank lookin and sniffin.

Birdman, lol I know which is why the little dash display said something like, fuel cap leak, was funny to me too. Oh well ODBII can't know all. When I worked in an auto parts store fuel vapor leaks were a nightmare for customers. I should have taken a picture.

cparksjr, Yeah thats what I was thinking. I used my mechanics mirror to check out all the connections from the back of the fuel filler metal to the rubber down tubes. I didn't see anything looking or smelling fishy from there.

I figured out by pushing gently on the two tabs on left and right side of the cap the flapper door opens but it looked like a nightmare to attempt to take apart. The wheel well has a solid bump guard rock protector to keep those soft tubes safe but it makes working on it extremely difficult.

Since I no longer see the message in the console I think the check engine light is just retaining that code to be reviewed by a dealership/mechanic. I'll clear the code to see if it returns. If it does I'll try a little vaseline to lub the o-ring in the filler neck. In a dusty environment I bet little pieces of dust/debris might break the sealing surface just enough to allow enough leak by.

I figure at least I'll post how I fix it so if it happens to someone else they can find the info on the forum.
 

Jake Y.

Full Access Member
Joined
Aug 24, 2010
Posts
494
Reaction score
107
Location
Tucson, AZ
I have the same thing, had it for quite a while actually! The message is something to the effect of "check fuel filler neck." I'll check when I drive it later, would love to know where it comes from, mine is on all the time now
 
OP
OP
D

Drift

Member
Joined
May 6, 2013
Posts
6
Reaction score
0
Location
Tri-Cities, Washington
Yeah your right, I think thats what the message was. Its been months since its shown me the message. All I see is the engine light but the error code is fuel vapor leak related. I'm a lazy mechanic, a fuel vapor leak doesn't chug like a 6.2L.
 

Mil T

Full Access Member
Joined
Oct 20, 2011
Posts
445
Reaction score
377
Location
Payson, Az
Vaseline might attract more dirt etc. than it would help.
Maybe use some carb cleaner to clean the o-ring and see if it makes a difference.
Mil T
 
OP
OP
D

Drift

Member
Joined
May 6, 2013
Posts
6
Reaction score
0
Location
Tri-Cities, Washington
Mil, I think your right it probably would do more harm then good.

I got my KIWI yesterday.

The code was P0456.

Evaporative Emission System Leak Detected (very small leak).

I think maybe the flapper door might have bumped and leaked during some spirited desert driving which caused the "Check Fuel Filler Neck" dash note and the check engine light. Once the leak stopped, maybe once I refilled the tank later the engine light stayed on to note and store the code. I cleared the code and it hasn't returned. I'm no certified mechanic and I didn't think an emissions system leak should/would have anything to do with a fuel filler neck. I thought that was typically related to the EGR being a craptastic addition to our automotive fleet but oh well.

Will post additional note of engine light returns. I've gone a few hundred miles since yesterday so I think its been "Relegated to the past tense" - Lucky Number Slevin.

By the way Dash Command is so stinkin cool. Digital intake temp, coolant temp, MAP, MAF, accelerometers. My new favorite toy =)

WIFI broadcast has about .5 second delay on throttle but of coarse data logging doesn't care. With a do over I think I would still just try to find a direct connection instead of WIFI/Bluetoof broadcast. My co-pilot likes the data too = )
 
Last edited:
Top