Fuel Tank Fill Problem Resolution
 

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.

I had the same problem and figured it out. Here's my thread w/ my fantastic hand-drawn explanations. :grin:

http://forums.bradbarnett.net/showthread.php?t=462079

Good write-ups guys...Glad they took care of you

If the voltage reading was of the pressure sensor, it just means there was a spike in pressure - NOT voltage. 3V sounds way too low for the pump voltage. Almost everything runs 12V DC. 3V sounds like a sensor output.

The voltage reference was in the instrumentation used to monitor the pressure in the tank... per Advisor, all the tech was noting was that he witness a jump of voltage required to pressurize the tank, thus concluding there must be a partial blockage in the EVAP Emissions System.

Like I said, that 2V-3V is in reference to the fuel tank pressure sensor output/reading, not a pump or other mechanism which would run off +12VDC. There is a PID for the fuel tank pressure that is given in volts and is part of the PCED procedures for diagnosing evap related DTCs.

Metroplex: you are exactly correct..:nice: thx for the feedback. I spoke directly with the Technician today and he confirmed the voltage reading was from the fuel tank pressure sensor. When voltage spikes too high on this sensor, it is 'sensing' excessive pressure and will force the gas pump to shut off. The Service Advisor is the one who said the voltage reading was from the instrumentation unit doing the test... that was incorrect... it was FTP sensor.

are a lot of people still having this problem??

The problem has been fixed. I believe somewhere in the 2007 builds. I don't know at what point in 2007 though. I will try to find out and let you know.

My 2007 was built November 2006 and has this problem.

FYI, I was filling up my 2000 Crown Vic and gas sprayed everywhere. The gas pump nozzle didn't cut-off automatically so my Vic was treated to a nice bath of gasoline. I almost got some on my sneakers but my experience with the Mustang taught me to keep my foot away just enough to avoid the splash.

Not entirely. There's 2 different problems, Ford only addressed one. Ford took care of the left side venting issue and there's an updated tank that's now being put on, and is avail through a TSB. The problem in this thread is the 'other' problem. Even after I got the updated tank, I then had the venting problem through the right side. Ford's new tank doesn't address this problem, as the problem is in the emissions crap in the rear of the car.

Let me add some clarifications to 05GT-O.C.D’s point: The tank that Ford redesigned is only for S197s build before 04/26/05. Per TSB 06-3-13, “On 2005 Mustang vehicles built on or after 4/26/05 and 2006+ model year vehicles were built with the revised design fuel tank. As a result, replacing the fuel tank on these vehicles will not change the occurrence of premature automatic fuel fill shut off. Occurrences of premature shut-off may be resolved or improved by using a different filling station fuel pump.” 05GT-O.C.D makes a good point that the updated tank design does not address the venting problem through the EVAP Emissions system. The points of failure (that can cause premature fill shutoff) along the fuel fill path are (in order of fuel/vapor flow): (1) fuel filler neck, (2) fuel inlet hose, (3) fuel tank check valve, (4) fuel tank, (5) fuel vapor control valve, (6) vapor tube, (7) evap canister, (8) evap canister purge valve, (9) vapor tube back to Intake. Any one or combination of these components will cause problems.

Now for the interesting news. I received this information yesterday from a very reliable source (Ford Technician not to be named or location divulged for obvious reasons). This Technician has encountered the fuel fill issue on numerous occasions and as a result, a Ford Rep and Ford Engineer were sent out. Technician asked why Ford has not come up with a re-design to address this continued problem. The Ford Engineer told the Technician that in fact Ford did come up with a re-design for the filler-neck and inlet tube which did fix the premature fuel shutoff. The problem is the convoluted inlet tube with the numerous turns and bends. As a matter of fact, if you look under your car (as I did after hearing this), you will see that the fuel inlet hose drops down from the filler neck, goes under a cross member, then back up slightly before reaching the tank. At about the halfway point, the inlet tube actually has to go uphill to the tank! The Ford Engineer explained that the new design involved a complete re-routing of the inlet tube. The re-route involved drilling through into the trunk area (behind fuel door) and run the inlet hose into the side trunk area, then back and down (through trunk rear floor) to the tank…eliminating some turns and the uphill run to the tank. The Engineer went on further to say this “fix” was not rolled out due to the inherit cost of all the retrofits… apparently Finance vetoed the “fix”.

As I stated, this is what I was told, and can only be considered hearsay. However, I tend to believe this as the Ford Technician would have no benefit (and much risk) in telling me this. If anyone out there can think of a way to substantiate this claim, please step forward. I’m sure the official Ford ‘fix’ re-design documents have all been shred by now along with the missing 4 minutes of audiotape from the design meetings! Maybe I watch too many movies, but this sounds unnervingly similar to Gene Hackman’s “Class Action”.

Anyway, take it for what it's worth...the real issue is the filler neck and inlet tube. If everything downstream of the tank (EVAP emission system) is in excellent working order, and all the proper stars are aligned, you can fill the tank completely (both saddle tanks). However, if any of these downstream components is not working at or near 100% of it's designed capacity (like my EVAP canister and canister vent solenoid), then the combination of the faulty inlet hose design along with the downstream EVAP system will trigger the premature fuel shutoff... and you're hosed (no pun intended).

Retrofit costs and potential future safety lawsuits I'm sure were at the top of list when Ford decided to "shelf" this fix. For safety reasons, you'd think they could simply run the inlet tube into trunk area and mount it flush with the side of trunk running down and back... perhaps with a strong protective shield/tube encasing the fuel inlet tube. It certainly is not that well protected where it is now (between 1/4 panel and trunk with a plastic wire-loom type tube shield !)

I wanted to post back here whether my latest warranty repairs actually fixed the fuel fill issue. My (and this collective Forum's) quest to solve the premature nozzle shutoff continues. Ran the tank down to ~ 1-2 gallons and tried to fill per Ford's recommendation (slowest auto-fill speed & less than 1/4 tank)... NO DICE... got to 7 gallons and nozzle shut-off.. D^MN! The 1/2 nightmare continues. Even after a new EVAP canister... new canister vent solenoid... new EVAP filter.... successful testing of tank check valve... and other emission system valves, sensors and relays, it's still a one saddle-tank pony. I guess through process of elimination, it appears the Ford Tech and Ford Engineer are correct... it's got to be the filler neck and inlet hose. I've seen a few posts here (and other forums) from folks who said they had their filler-neck assembly "adjusted", which solved the problem. I took a look at the filler neck and can't quite figure out what was "adjusted". Does anyone know what kind of adjustment you can make to the neck? There's a funnel shaped attachment right behind the fuel door inlet, which narrows down and attaches to the inlet hose (inside of the plastic wire-loom tube). How is this adjusted? As I stated earlier, the inlet hose makes a few convoluted turns and at the half-way mark (between inlet door and fuel tank) it actually runs slightly uphill to tank (which I'm sure is not conducive to continuous flow). Appreciate if anyone could provide information to this mysterious filler neck adjustment and exactly how it is adjusted to allow uninterrupted flow and a full tank fill. Thx.