Fuel starvation on track

[JAJ]

I took a look at my 2016 CD Service Manual and I think I understand what FP did with the second pump.

If you look at the wiring diagram for the GT, it has one fuel pump control module (FPCM) managed by the PCM using two signals - FPC and FPM (Pins 14 and 27 on the PCM connector). The FPCM manages the fuel pump.

The GT350 wiring diagram shows two FPCM modules. One is controlled by signals FPC and FPM on PCM pins 14 and 27, while the second is controlled by signals FPC and FPM2 on PCM pins 14 and 31. On the GT diagram, PCM pin 31 is not used.

If you look at the instructions for removing and replacing the fuel pump module itself, both the GT and the GT350 show exactly the same steps. Unseal the top, disconnect the wiring and the fuel line to the engine, and unplug a crossover line inside the tank that pulls fuel from the right hand side of the tank.

So, from all that, I concluded that the GT fuel tank module uses a similar strategy to the one that BMW used in the description I provided here: https://www.mustang6g.com/forums/threads/fuel-starvation-on-track.184328/post-3772506

The single pump somehow creates enough vacuum on the crossover fuel line that it successfully draws fuel from both sides of the tank.

So, if there's a second pump in the GT350, what does it do? I'm guessing that the GT350's second pump is connected directly to the crossover fuel line and is managed separately by the PCM to reduce fuel starvation in high-g cornering.

There's no reason that a GT350 dual pump module wouldn't fit a GT fuel tank - same exact form-factor and connections. The trick would be controlling it.

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[ChipG]

Just as an update for all - the additional pump worked like a charm. As mentioned, previously on this track, fuel starvation was guaranteed when getting to maybe 5/8 of a tank, meaning I had to start a session basically full to ensure I had no fuel starvation issues throughout the session. With the new pump in I ran the same track on the same tires this weekend and ran nearly to empty without a single hiccup. For less than $100 invested and a couple of hours time, problem solved. Two thumbs up, would recommend.

 

[JAJ]

Just as an update for all - the additional pump worked like a charm. As mentioned, previously on this track, fuel starvation was guaranteed when getting to maybe 5/8 of a tank, meaning I had to start a session basically full to ensure I had no fuel starvation issues throughout the session. With the new pump in I ran the same track on the same tires this weekend and ran nearly to empty without a single hiccup. For less than $100 invested and a couple of hours time, problem solved. Two thumbs up, would recommend.

That's great - glad to hear it works! It's not obvious from your description, though, just how you hooked it up. Did you punch a new hole in the tank or is there a way to run new plumbing across through the existing pump portal? How'd you do it?

 

[ZXMustang]

Happens on both GT500 and GT350.

 

[ChipG]

That's great - glad to hear it works! It's not obvious from your description, though, just how you hooked it up. Did you punch a new hole in the tank or is there a way to run new plumbing across through the existing pump portal? How'd you do it?

I strapped the pump to the bottom of the passenger side hanger for the fuel level sensor with stainless zip ties and hose clamped a 3-ft Tygon yellow fuel hose to the output (similar to Scoots photos), then snaked the hose inside the tank across the top of the saddle. There is plenty of room, I just fed it through with my left hand and caught it with my right. I then clamped the far end to the driver's side hanger so that it points down into the fuel bucket for the stock fuel pumps (again, similar to the pictures Scoots shared). No new holes, all in-tank, and I didn't disturb or use any of the existing hose arrangement, so this is all incremental to the OEM system. I drilled a couple of holes in the top of the passenger side hat, put grommets in the holes, ran bolts through them with rubber washers above and below the grommet to ensure a good seal, then wired the pump with loop connecters and nuts to the bottom of the bolts so I had positive and negative "posts" out the top at the bolt heads. Loop connectors there as well, and about a foot farther along, spade connectors for connect/disconnect (for being able to remove/reinstall the passenger side hanger) then I ran the wires under the carpet up along the transmission tunnel (driver's side) and up behind the dash, where I connected to a switch I installed in the panel below to the right of the steering wheel. Grounded to a bolt and nut behind the dash attached to metal support bracketry, power by positap from the interior air temp sensor wire.

I would have liked to take photos and done a better write-up, but I was hustling to get the car together for the weekend so didn't take the extra time. Let me know if you have other questions, I'm happy to clarify or provide more detail.

 

[Clint81]

A quick question for the group, as I am hunting down a problem that could be related:
Did anyone get a flashing CEL or Cylinder Misfire Code (P030x) that corresponded to a fuel starvation event?
Thanks!

 

[ChipG]

A quick question for the group, as I am hunting down a problem that could be related:
Did anyone get a flashing CEL or Cylinder Misfire Code (P030x) that corresponded to a fuel starvation event?
Thanks!

I don't think I've ever gotten that.

 

[Tomster]

A quick question for the group, as I am hunting down a problem that could be related:
Did anyone get a flashing CEL or Cylinder Misfire Code (P030x) that corresponded to a fuel starvation event?
Thanks!

I've had this fuel starvation occur plenty of times. It never threw a code.

 

[Clint81]

I don't think I've ever gotten that.

I've had this fuel starvation occur plenty of times. It never threw a code.

Thanks guys, that is very helpful!

 

[Bossdog]

Wow, I was very suprised by this "fuel starvation" issue. I stumbled on it looking into E85. Why isn't the Fuel Starvation issue a sticky at the very top of the track and Autocross forum? Seems like it should be a #1 issue to be resolved before heading to the track. Keeping the tank full is a solution but it would be good to know that before you head to the track.( or even purchase this car for track use)

ChipG's solution is awesome, I am in awe of his knowledge, ingenuity, skill, etc. However, How many of us weekend trackers have the skill, knowledge and courage to mess around inside our fuel tank/system adding pumps and switches? Not many I would guess. NOT me!

The KPM solution looks like my type of solution, plug & Play. Although I do understand (i think) ChipG's point that it is not a Complete solutions and still leaves the core issue unresolved. It would be interesting to learn how much of a solution the KPM really is. Member @josephstef indicate it was a total solution down to below a 1/4 tank.
The Radium solution looks very doable as well.

Does anyone here know if the Mach 1 has the GT or GT350 fuel take up system?

 

[DougS550]

Thanks for all the input, folks. Some clarifications and thoughts:

• This isn't a quarter tank issue. I'll start seeing fuel starvation when hitting between 5/8 and 1/2 tank during the session. If I start with over 3/4 tank I can generally finish out a 15 minute session. Anything else and I get fuel starvation before the session ends.
• The sessions are 15 minutes and the full tank is a concern for me because I'm running Time Trials, not HPDE. Finishing a session with 5/8 tank vs 1/8 tank is nearly 50 pounds of weight.
• That said, this is a dual purpose car that is also daily driven. I hope to only use it for time trials for one more season as I'm working to get a dedicated track car built (SN95 Cobra), at which point the Shelby moves back to being an occasional HPDE car when running outside of NASA events (Chin, etc.).

To this point, my solution has indeed been to just keep the tank topped up. Fortunately it's a bit less of a hassle than it could be because I have a transfer tank in my truck and I just fill up from there in the paddock. However, it's a hassle anyway after every session and, as I said, the extra weight sucks. Thanks for all the leads on surge tank options. I'll dig into those and consider them as options vs. sucking it up and running full and heavy when here at NSS. Also interesting to hear that the GT500 has solved this with dual pickups. Has anybody looked into what it would take to adapt the GT500 setup to a GT350? For a dual purpose car, the OEM solution has appeal as a 3rd option especially if it's cheaper and/or easier than a surge tank install.

I think them using a 1/4 tank, was to show the worst case senereo which would be almost an empty tank.

 

[DougS550]

Wow, I'm a little overwhelmed by all this "fuel starvation" issue. I stumbled on it looking into E85. Why isn't the Fuel Starvation issue a sticky at the very top of the track and Autocross forum? Seems like it should be a #1 issue to be resolved before heading to the track. Keeping the tank full is a solution but it would be good to know that before you head to the track.( or even purchase this car for track use)

ChipG's solution is awesome, I am in awe of his knowledge, ingenuity, skill, etc. However, How many of us weekend trackers have the skill, knowledge and courage to mess around inside our fuel tank/system adding pumps and switches? Not many I would guess. NOT me!

The KPM solution looks like my type of solution, plug & Play. Although I do understand (i think) ChipG's point that it is not a Complete solutions and still leaves the core issue unresolved. It would be interesting to learn how much of a solution the KPM really is. Member @josephstef indicate it was a total solution down to below a 1/4 tank.

Does anyone here know if the Mach 1 has the GT or GT350 fuel take up system?

My friend running E85 on his Roush Ford truck told me he has to keep his tank over half full or he starts burning up pumps. He has a Fore return system which is a bucketless fuel hat assembly. He's also the Ford Performance service rep at my local Ford Dealership.

 

[Bossdog]

Just as an update for all - the additional pump worked like a charm. As mentioned, previously on this track, fuel starvation was guaranteed when getting to maybe 5/8 of a tank, meaning I had to start a session basically full to ensure I had no fuel starvation issues throughout the session. With the new pump in I ran the same track on the same tires this weekend and ran nearly to empty without a single hiccup. For less than $100 invested and a couple of hours time, problem solved. Two thumbs up, would recommend.

ChipG, thanks for sharing your efforts on this important issue for us trackers.
Perhaps my understanding of your solution (and/or of fuel pumps) is not 100% but I have a question: what happens in the case of (for example) 1/3 fuel level, total and the passenger side auxiliary' pump has emptied the passenger side, I am assuming while on track the pump remails running. Is that a problem for the pump? running with no fuel?

 

[ChipG]

ChipG, thanks for sharing your efforts on this important issue for us trackers.
Perhaps my understanding of your solution (and/or of fuel pumps) is not 100% but I have a question: what happens in the case of (for example) 1/3 fuel level, total and the passenger side auxiliary' pump has emptied the passenger side, I am assuming while on track the pump remails running. Is that a problem for the pump? running with no fuel?

The fuel pump I'm using is, I believe, pretty tolerant of running dry. That said, I keep it on a switch I only turn on for the track session, so the amount of time it potentially runs dry (when the passenger side is empty) is limited. If I were running a track that is the opposite of my home track (mostly clockwise Gs keeping fuel pushed to the driver side) I could simply not use the pump. If I do end up burning out the pump, it's not super expensive, and with the rest of the installation done, replacement would be pretty simple as well.

 

[Angrey]

DW claims their micro lift pumps can run dry for an hour without failing.

I didn't trust that so I installed a manual power switch mounted to the rear bulkhead of the console.

If you're willing to deal with the MIL/code, you can paint an insulator coating to the bottom of the float unit clock, then run power through it to a relay that triggers the pumps. That way the pump will always run with fuel but shut off when the passenger side saddle gets low.

In that configuration, your fuel Guage will read 1/2 at full and only receive input from the drivers saddle.

I tried everything to run an autometer Guage that would trigger the pumps in high and low conditions but it just won't work (the gauge) so I think automated is getting away with false advertising, because after 4 calls with them we couldn't get it to work properly.

So you could just run them all the time, manually switch them (I recommend a 3 position switch so you don't run the battery down if you forget) ot you can automate a bit but mess up Fords dumbass fuel level logic. The fuel senders aren't a standard ohm resistant signal. Like so many things, Ford engineers could uck up a cup of coffee. I had a helluva time just finding an aftermarket gauge that would work

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