About 4 weeks ago I posted a poll regarding the fuel fill issue. I wanted to share those results (which I took to my meeting with Ford) with this forum along with events from the meeting. The poll question asked if forum members have experienced the premature fuel nozzle shut-off while attempting to fill their tanks (usually shutting off after ½ tank). I posted the poll on 3 separate S197 Mustang Forums with the following results:
224 Total Responses:
20% (44) responded that they ALWAYS encounter the fuel fill issue.
51% (115) responded that they have encountered the issue, but not all the time.
29% (65) responded that they have NEVER encountered the fuel fill issue.
Now, I know this poll may not subscribe to accepted scientific study standards, however, most of data was collected within days of the posted poll. IMO, this is a surprisingly high percentage (71%) of S197 owners who have experienced this fuel fill issue (either all the time, some of the time, or resort to flipping/inverting nozzle in order to fill their tanks).
Background: I have an 06GT (18 months since I drove off the lot). For the 1st year, I would encounter the fill issue about every 3rd or 4th fill-up… stopped at half-tank each time. I tried all the tricks to re-engage the fill (turning nozzle.. inverting nozzle…), no dice. No additional fuel could be added. During the past 6 months, the problem began to escalate to just about every fill-up. Finally decided I’ve had enough and scheduled my first fuel-fill warranty service trip. Ford found that the EVAP Canister was slightly obstructed causing excessive tank pressure build-up as the tank was being filled. They did this by monitoring the FTP (Fuel Tank Pressure) sensor. Sensor voltage started out at 2.6v, then reached 3.5v at ½ tank. As was explained to me, any voltage above 3.5v is too high, meaning excessive tank pressure is being experienced. Fuel system interpret this as tank is full (no room left for fluid), and causing pump to shut off. This voltage should never exceed 3.2 – 3.3v. Ford replaced my entire EVAP Canister assembly tray (EVAP canister, canister vent solenoid, EVAP filter), cleaned all the lines, checked purge-valve, tank check-valve, and tank pressure…all was good. Within 3 weeks, issue came back; however, after the ½ tank fill stop, I was now able to invert the nozzle to 2-o-clock position, and continue to fill tank completely. So I contacted Ford dealership and they arranged for a Ford Rep to come out. I was instructed to return to the dealership with less than ¼ tank. Upon arrival, the Ford Rep was a no-show, but he left instructions with the Service Manager insisting we take my car to a station of his choice, as he claimed the issue is with certain stations (fuel flow rates) and nozzle design. I refused and shared with them that I bought this vehicle in good faith assuming I could get gas anywhere of my choosing… dealership lead tech agreed, so we piled in my S197 and headed to my local fueling station. Ford’s Drivability Lead Tech hooked up his laptop to the OBD port then instructed me to open tank cap and begin filling. I was also instructed to lock the pump on the lowest speed auto fill and do not touch it (i.e., “step away from the nozzle”). He monitored the FTP sensor voltage as the tank filled. Sensor started out at 2.6v.. .then slowly climbed to 3.1v, but no higher (due to the new EVAP canister assembly). CLICK… tank shuts off @ ½ tank. This was actually good news as it indicated that excessive pressure was not to blame (as it was before) for the premature nozzle shutoff… but something else. I then challenged him to attempt to fill tank completely. He tried, several times, unsuccessfully. I then showed them by inverting nozzle to 2 o clock position I could continue to fill up… and fortunately this worked… the remaining 7.5 gallons (right side saddle tank). Ford’s Drivability Lead Tech stated this proved it is NOT just an EVAP emissions pressure issue, but also a filler neck design issue. He shared with me that the Ford Rep had previously shared with him that Ford was aware of the S197 tank design flaw, and they have encountered this fuel fill issue numerous times. Midpoint mounted saddle tanks… in a lower-profile vehicle… with all the required EVAP emissions systems, just don’t play well together (late model Corvettes have this same issue). Many things must come together in order to fill our tanks completely: (1) proper filler neck angle (more on this below); (2) pristine EVAP emissions system; (3) slow fuel fill rate. When excessive tank pressure builds, station nozzles will shut off. The S197 has multiple points causing back pressure: tank inlet check valve, saddle tank design and improper venting, inlet filler neck hose size and inlet hose angle, EVAP emissions system (EVAP canister, canister vent solenoid, EVAP filter, canister purge valve, FTP sensor, etc, etc).
So here is what they did: We returned to the dealership, put my rig up on the lift, and the Ford Drivability Lead Tech showed me the inlet hose issue. This hose attaches directly to tank inlet, and in most cases, is a bit too long and improperly angled. He disconnected this inlet hose and cut off approximately 3/8 of an inch (depending on each car, this can vary). He cut off enough to angle the tube directly down to the tank inlet flange. Shortening the hose also required lowering the hose support bracket. Lowering the hose support bracket required adding a spacer between bracket and body. This spacer allowed the bracket to drop down another ½ inch helping the overall inlet angle to tank. See pictures below. Next 2 fill-ups (at the same station, same pump where I ran into the fill issue) no stoppage! Tank filled to full each time without stopping. On the record, Ford said this issue is caused by the variability of each station’s pump pressure and nozzle design.
Off the record, Ford admitted the issue is caused by the inherit S197 tank design flaw. They also said they are aware of the issue and designed a fix about a year ago; however, this fix involved re-routing the inlet hose through the trunk and strait down to the tank. Two problems with this fix: (1) too costly for Ford to retrofit all the problem S197s on the road; (2) safety concerns with routing fuel into trunk area. Bottom-line: Ford abandoned this fix.
Now, why don’t all S197s have this issue? It appears that for issue to surface, (1) vehicle’s EVAP emissions system has a slight obstruction (either due to dirt or kinked evap hoses), AND/OR (2) fuel inlet hose is improperly angled and slightly too long (causing a slight upward rise in hose immediately before attaching to tank), AND/OR (3) fuel fill rate is too fast and/or filling station tank pressure too high. So, if you’ve never encountered this issue, feel fortunate all the “saddle-tank filling stars” are all aligned in your favor. However, keep in mind over time, your EVAP emission system will begin to become dirty, and that may be just enough to tip the scales to the ½” fill syndrome down the road.
Sorry for the lengthy post, but I wanted to provide feedback to possibly help those still plagued with the fuel fill issue. For some, cleaning (or replacing) the EVAP canister/ emissions system is enough to allow full tank fill. For others (like me), it took both the replacement of the EVAP canister assembly and re-angling of the fuel filler neck. Will this permanently solve my problem? Time will tell. As for now, it works. Good luck and hope this helps those still in need. Here are the links to my other tank fill threads:
About 4 weeks ago I posted a poll regarding the fuel fill issue. I wanted to share those results (which I took to my meeting with Ford) with this forum along with events from the meeting. The poll question asked if forum members have experienced the premature fuel nozzle shut-off while attempting to fill their tanks (usually shutting off after ½ tank). I posted the poll on 3 separate S197 Mustang Forums with the following results:
224 Total Responses:
20% (44) responded that they ALWAYS encounter the fuel fill issue.
51% (115) responded that they have encountered the issue, but not all the time.
29% (65) responded that they have NEVER encountered the fuel fill issue.
Now, I know this poll may not subscribe to accepted scientific study standards, however, most of data was collected within days of the posted poll. IMO, this is a surprisingly high percentage (71%) of S197 owners who have experienced this fuel fill issue (either all the time, some of the time, or resort to flipping/inverting nozzle in order to fill their tanks).
Background: I have an 06GT (18 months since I drove off the lot). For the 1st year, I would encounter the fill issue about every 3rd or 4th fill-up… stopped at half-tank each time. I tried all the tricks to re-engage the fill (turning nozzle.. inverting nozzle…), no dice. No additional fuel could be added. During the past 6 months, the problem began to escalate to just about every fill-up. Finally decided I’ve had enough and scheduled my first fuel-fill warranty service trip. Ford found that the EVAP Canister was slightly obstructed causing excessive tank pressure build-up as the tank was being filled. They did this by monitoring the FTP (Fuel Tank Pressure) sensor. Sensor voltage started out at 2.6v, then reached 3.5v at ½ tank. As was explained to me, any voltage above 3.5v is too high, meaning excessive tank pressure is being experienced. Fuel system interpret this as tank is full (no room left for fluid), and causing pump to shut off. This voltage should never exceed 3.2 – 3.3v. Ford replaced my entire EVAP Canister assembly tray (EVAP canister, canister vent solenoid, EVAP filter), cleaned all the lines, checked purge-valve, tank check-valve, and tank pressure…all was good. Within 3 weeks, issue came back; however, after the ½ tank fill stop, I was now able to invert the nozzle to 2-o-clock position, and continue to fill tank completely. So I contacted Ford dealership and they arranged for a Ford Rep to come out. I was instructed to return to the dealership with less than ¼ tank. Upon arrival, the Ford Rep was a no-show, but he left instructions with the Service Manager insisting we take my car to a station of his choice, as he claimed the issue is with certain stations (fuel flow rates) and nozzle design. I refused and shared with them that I bought this vehicle in good faith assuming I could get gas anywhere of my choosing… dealership lead tech agreed, so we piled in my S197 and headed to my local fueling station. Ford’s Drivability Lead Tech hooked up his laptop to the OBD port then instructed me to open tank cap and begin filling. I was also instructed to lock the pump on the lowest speed auto fill and do not touch it (i.e., “step away from the nozzle”). He monitored the FTP sensor voltage as the tank filled. Sensor started out at 2.6v.. .then slowly climbed to 3.1v, but no higher (due to the new EVAP canister assembly). CLICK… tank shuts off @ ½ tank. This was actually good news as it indicated that excessive pressure was not to blame (as it was before) for the premature nozzle shutoff… but something else. I then challenged him to attempt to fill tank completely. He tried, several times, unsuccessfully. I then showed them by inverting nozzle to 2 o clock position I could continue to fill up… and fortunately this worked… the remaining 7.5 gallons (right side saddle tank). Ford’s Drivability Lead Tech stated this proved it is NOT just an EVAP emissions pressure issue, but also a filler neck design issue. He shared with me that the Ford Rep had previously shared with him that Ford was aware of the S197 tank design flaw, and they have encountered this fuel fill issue numerous times. Midpoint mounted saddle tanks… in a lower-profile vehicle… with all the required EVAP emissions systems, just don’t play well together (late model Corvettes have this same issue). Many things must come together in order to fill our tanks completely: (1) proper filler neck angle (more on this below); (2) pristine EVAP emissions system; (3) slow fuel fill rate. When excessive tank pressure builds, station nozzles will shut off. The S197 has multiple points causing back pressure: tank inlet check valve, saddle tank design and improper venting, inlet filler neck hose size and inlet hose angle, EVAP emissions system (EVAP canister, canister vent solenoid, EVAP filter, canister purge valve, FTP sensor, etc, etc).
So here is what they did: We returned to the dealership, put my rig up on the lift, and the Ford Drivability Lead Tech showed me the inlet hose issue. This hose attaches directly to tank inlet, and in most cases, is a bit too long and improperly angled. He disconnected this inlet hose and cut off approximately 3/8 of an inch (depending on each car, this can vary). He cut off enough to angle the tube directly down to the tank inlet flange. Shortening the hose also required lowering the hose support bracket. Lowering the hose support bracket required adding a spacer between bracket and body. This spacer allowed the bracket to drop down another ½ inch helping the overall inlet angle to tank. See pictures below. Next 2 fill-ups (at the same station, same pump where I ran into the fill issue) no stoppage! Tank filled to full each time without stopping. On the record, Ford said this issue is caused by the variability of each station’s pump pressure and nozzle design.
Off the record, Ford admitted the issue is caused by the inherit S197 tank design flaw. They also said they are aware of the issue and designed a fix about a year ago; however, this fix involved re-routing the inlet hose through the trunk and strait down to the tank. Two problems with this fix: (1) too costly for Ford to retrofit all the problem S197s on the road; (2) safety concerns with routing fuel into trunk area. Bottom-line: Ford abandoned this fix.
Now, why don’t all S197s have this issue? It appears that for issue to surface, (1) vehicle’s EVAP emissions system has a slight obstruction (either due to dirt or kinked evap hoses), AND/OR (2) fuel inlet hose is improperly angled and slightly too long (causing a slight upward rise in hose immediately before attaching to tank), AND/OR (3) fuel fill rate is too fast and/or filling station tank pressure too high. So, if you’ve never encountered this issue, feel fortunate all the “saddle-tank filling stars” are all aligned in your favor. However, keep in mind over time, your EVAP emission system will begin to become dirty, and that may be just enough to tip the scales to the ½” fill syndrome down the road.
Sorry for the lengthy post, but I wanted to provide feedback to possibly help those still plagued with the fuel fill issue. For some, cleaning (or replacing) the EVAP canister/ emissions system is enough to allow full tank fill. For others (like me), it took both the replacement of the EVAP canister assembly and re-angling of the fuel filler neck. Will this permanently solve my problem? Time will tell. As for now, it works. Good luck and hope this helps those still in need. Here are the links to my other tank fill threads:
I have a 2005 mustang gt it was having the same problem. For the 2005 there is a TSB for this problem. They replaced the whole tank. This solved the problem. Check the tsb list on this forum for the details.
Thanks for posting the TSB. This TSB does not apply to late-build date 2005s or 2006+. I have heard from a few folks with early 05s that this TSB tank replacement still did not solve the fill issue. You may be one of the fortunate ones with the correctly angled filler neck.
Sounds like you may have finally found the real fix. Think this could be a DIY job?
I sure hope this turns out to solve the problem... after a few more fill-ups (at various stations), I'll feel more confident. As far as DIY, a lift certainly helped. When tech disconnected inlet hose (and of course tank was full), he did a 'pull and run' move.. as fuel gushed out. Even with the tank check valve, it was enough to run down and under the tank liner and slightly pool on floor (some fuel may have still been in inlet hose). Without a lift, I can't imagine laying on my back and attempting a "pull-n-roll" move! Anyway, I'll keep everyone posted on this fix.. if it proves to have solved the issue for me, most likely this will be a valuable aid to others.
I have an '07, which started having the problem more and more. The dealer said I had the new tank design, but replaced it anyway a couple of months ago. That solved my problem--until last night!
Awesome info! Thanks for sharing.
I know I never had the issue, but I know there's a lot out there that have and hopefully can get a fix before warranty is out.
Fuel Tank Fill Update: 2nd Fix by FORD 
