DoctorQ

I, like many others on this Forum, have been plagued with the dreaded fuel fill problem. Mine started from day 1 (the day I bought the GT, the dealership tried to fill tank and only got ½ tank filled… we all assumed it was their pump). I’ve had my GT for 18 months now (14K miles), and run into the fill issue about every 3rd or 4th fill-up. Each time I ran the tank down to the “50 mile” warning, and when filling, set pump at slowest fill speed. When issue does surface, I can only get ½ tank in before pump shuts off...and fuel is all the way up in the filler neck. I’ve even crawled under the car at station and tapped on the saddle tanks… finding the left saddle tank filled while the right saddle tank sound like the tin-man (empty). OK, now on to the news you can use. I took car in yesterday for the RCM Module (airbag) reflash. While there, I told them I’ve had it with the fuel fill issue. I was really impressed with the dealership as they really owned up to the problem (stating they had run into a number of these in the last 2 years) and methodically trouble-shot the problem. Here’s an excerpt of the work-order notes:

“Using IDS and ran EVAP test. Vehicle pass test. Tried to add gas and monitor fuel tank pressure. Started out at 2.6 volts then it jumped to 3.5 volts to HIGH. Disconnect each line one by one to check for blockage. Found Charcoal EVAP Canister plugged. Replaced Charcoal canister assembly. Retest OK. Also removed fuel filler neck and inspected, OK. Inspected check valve in fuel tank, OK.

Note to Customer: This vehicle is equipped with SADDLE style tank which has two sections. Vehicle will not fill up completely unless the tank is below ¼ tank and unless you are using the “autofill” function on pump on the lowest flow setting”.

So, based on their notes, it appears while they were measuring the pressure in the tank, they witnessed a voltage jump. Assuming this means it was requiring additional current to attempt to "fill" or force air out of the right saddle tank via the EVAP system... thus concluded there was a slight obstruction (a.k.a, charcoal EVAP canister). They installed the new EVAP canister assembly, and I'm happy to report that today (while nervously adding fuel), was able to fill to 100% capacity!.

They also stated that they eliminated other possible concerns such as:

(1) Fuel Filler Neck (visual inspection and performed adjustment)
(2) Fuel Vapor Control Valve (electronically tested and passed)
(3) EVAP Canister (failed and replaced)
(4) Fuel Tank Pressure (FTP) Sensor: (electronically tested/passed)
(5) Canister Vent Solenoid: (replaced with EVAP Canister)
(6) EVAP Canister Purge Valve: (electronically tested/passed)

It appears there are many potential failure points in the Evaporative Emissions system which could cause the saddle tank fill issue… in my particular case, looks like it was the EVAP Canister and/or Canister Vent Solenoid (both replaced). The Service Manager did share with me up front that these types of issues can be difficult to resolve as FORD requires test failure documentation before authorizing part replacements (under warranty). My hat’s off to Folsom Lake Ford as their Tech was able to produce this failure (blockage) through the tank pressure test.

Anyway, sorry for the dissertation, but wanted to provide this to those still plagued with the fuel fill issue. Perhaps your issue is also tied to a partially blocked EVAP Canister and/or intermittent Canister Vent Solenoid. I guess only time will tell if in fact this did fix my issue (as I’d feel better after a half dozen successful full tank fills at various stations). Hopefully, based on what they found, looks like this may have solved the Pony feed issue.

luckydawg003

Ya I noticed my car doing that the other day. I turned the pump sideways and it filled up after spilling some fuel on my rear quarter panel

hammeron

thanks for the writeup doc, i saved this
for future reference, incase i start to
have fill issues

Kara

Awesome write up. I have this problem!

User 113021

Maybe I should get this fixed. I'm tired of getting weird looks when I turn the pump handle upside-down just to fill up.

olvanish

My car does that too. I figured it was a Mustang thing because it's never done it before on my other cars but now it happens on every other gas station. I think I should do the same thing as you and bring it in so they could fix it because it annoys the crap out of me

157dB

Mine did it from day one,207 miles on the vehicle.
I hopemy evapcanister was not plugged from the factory. [:@]

300GT

thanks for the write-up - just printed it out for my Mustang binder. I haven't had this problem yet with the 'stang [knocks on wood] but my wife's Camry does it all the time, so I don't think the problem is isolated to Mustangs/Ford.

PennState

its soo embarssing when it does this.

GidyupGo

It's a tank design issue. I'm 100% positive that you will experience the same fill up problems in the near future. Mine will fill up if it is low on gas and I start the fuel at a slow setting. Once I get it flowing, I can go ahead and boost the flow up the full bore. The other day, I was above 1/2 on the tank and filled it up. It did the shut off thing until I turned the handle. My conclusion is the tank needs to be close to empty for a satisfactory fill up.