Throttle cutting out in hard left turns !!!

[NightmareMoon]

On the topic of fuel starvation - yeah did that today.

Honestly I wasn't trying to test the fuel limits, but I underestimated the Mustang's epic thirst again and found myself at the front of the grid with only about 1/3 of a tank left and figured I'd just run until it got low and quit the last session a few minutes early, which is exactly what happened.

About 10 minutes in, holding a 1.0-1.1g left sweeper (with T/C and AdvTrac fully off) it starved.

Fuel starvation was pretty obvious, gas pedal didn't work at all for more than a few moments and a couple of tries, but fuel came back after the corner and I proceeded to pit and head straight to the gas station (4 miles away).

When it starved, I probably had a 1/8th of a tank or less, plus +1 gallon (so ~2-3 gallons left?). Its a little hard to say because the fuel needle lags so much when you're drinking gas as fast as 4-5 mpg. I imagine the starvation it could kick in sooner if you corner significantly harder than I do.

That's the first time I've experienced it, and the fuel gauge needle had finally coasted down to zero by the time I got to the gas station (1 gallon left?). The struggle is real.

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[bluestang50]

Well I ran into the fuel starvation issue at AMP yesterday. My first two twenty minute sessions out I did not have a problem at all. Towards the end of my third session I was pushing hard through the left sweeper trying to catch someone before the front straight to be able to pass. Right as I was about to straighten the wheel to start going back right onto the front straight is when I felt it. Just like everyone else it felt like I lost power for a second or two it slightly bucked and then power came back.

My fourth session out I tried really straightening the car out between the inside apex and where you track out to the outside before turning back in (the section where you start shooting for the white sound barrier on the right side of the track before the right onto the front straight). By doing that I did not have a problem again until I was pushing hard to try to catch someone to be able to make a pass on the front straight. This time I had fuel starvation really bad. It was bad enough that CEL lit up and was flashing like crazy and I was without power for about 5 seconds. The car was surging in and out of power which was pretty scary because I was pretty much at the limit of grip when it happened. It definitely unsettled the chassis, but I was able to control it and slow down.

I am definitely going to be doing the foam in the tank hack to hopefully fix this issue before next season.

I have video of all of my sessions so I will post up the video of the bad fuel starvation in the next couple of days.

 

[ddozier]

This time I had fuel starvation really bad. It was bad enough that CEL lit up and was flashing like crazy and I was without power for about 5 seconds. The car was surging in and out of power which was pretty scary because I was pretty much at the limit of grip when it happened. It definitely unsettled the chassis, but I was able to control it and slow down.

I am definitely going to be doing the foam in the tank hack to hopefully fix this issue before next season.

I have video of all of my sessions so I will post up the video of the bad fuel starvation in the next couple of days.

How much fuel did you have in the tank when it started, were you filling between sessions?

I have found the fuel gauge for track use to be very inaccurate. I try and keep track of fuel usage at any given event by going out the first session with a full tank then topping off before the 2nd session. Keeping track of the fuel that is needed to top off in between the first two sessions lets me know how much fuel is really in the tank so I do not let it get below a 1/3 of a tank. Some tracks it will not matter as you may not be in a sustained high g turn long enough to have the issue.

Good luck with the foam it really is not to bad to put in, just take your time and make sure you have a brass punch to get the retaining ring off the passenger side sending unit, you do not want to use a steel punch or screw driver as it may cause a spark near the open fuel tank. It is best to have the car near empty on fuel so the passenger side of the tank will be bone dry.

Dave

 

[bluestang50]

How much fuel did you have in the tank when it started, were you filling between sessions?

I have found the fuel gauge for track use to be very inaccurate. I try and keep track of fuel usage at any given event by going out the first session with a full tank then topping off before the 2nd session. Keeping track of the fuel that is needed to top off in between the first two sessions lets me know how much fuel is really in the tank so I do not let it get below a 1/3 of a tank. Some tracks it will not matter as you may not be in a sustained high g turn long enough to have the issue.

Good luck with the foam it really is not to bad to put in, just take your time and make sure you have a brass punch to get the retaining ring off the passenger side sending unit, you do not want to use a steel punch or screw driver as it may cause a spark near the open fuel tank. It is best to have the car near empty on fuel so the passenger side of the tank will be bone dry.

Dave

Unfortunately I was not able to refuel between sessions. In session three when the minor cut out happened I was between 3/4 of a tank and 1/2 a tank. After the fourth session I was under half a tank, but over 1/3 of a tank.

PS thanks for the tip on the brass punch!

 

[bluestang50]

Here is the lap from my fourth session when I experienced the worst fuel starvation.



I am very curious to know if any of the GT350/GT350R guys have had any issues with fuel starvation. If not I wonder what design changes were made with their tanks and if they could fit a GT as a permanent fix.

 

[EFI]

Do you guys think there's going to be any long term/catastrophic issues when dealing with fuel starvation or is it just a temporary hiccup and nothing more?

I'm afraid that if you lose fuel pressure and go hard on the throttle that you will go extremely lean and risk doing damage to the pistons? Or does the computer dial back power in order to prevent any damage from lean conditions?

 

[wildcatgoal]

Computer will dial back power - may not if you have a tune, depends on tuner.

 

[wildcatgoal]

Here is the lap from my fourth session when I experienced the worst fuel starvation.



I am very curious to know if any of the GT350/GT350R guys have had any issues with fuel starvation. If not I wonder what design changes were made with their tanks and if they could fit a GT as a permanent fix.

What do I have to listen for to "hear"/"see" this stavation - I guess there's so much noise I'm not picking up on it.

Like I said earlier, same track, my only issue seemed to be grip (and basic bitch driving skills...).

And where did you get this lap timer thingy?

Also, raise the camera so we can see over the 900 ft hood to see you hit the apex.

 

[bluestang50]

What do I have to listen for to "hear"/"see" this stavation - I guess there's so much noise I'm not picking up on it.

Like I said earlier, same track, my only issue seemed to be grip (and basic bitch driving skills...).

And where did you get this lap timer thingy?

Also, raise the camera so we can see over the 900 ft hood to see you hit the apex.

Watch my speed just after the 1:29 mark. You will see right as I am about to hit the apex my speed starts to drop very quickly. That is when it started starving and I didn't return to full power until about the start/finish line.

lmao about the hood. I have the MMR mount that uses the head rest posts to attach. I had it mounted on the passengers side and had the seat tilted pretty far forward to even be able to see that much. ohhh crap as I am typing this I just realized I could have raised the seat..... doh. lol

The lap timer is "Harry's Lap Timer" it is an app you can download on android and apple devices. It is the pertolhead version and was only $20. As you get more serious you can add external sensors like a better GPS antenna and OBD II scanners that connect via bluetooth . I am going to pick up a vbox GPS which will be 20hz (20 locations per second) versus my phone only hitting about 1hz (one location per second). That will give me much more accurate speed and track mapping. The OBD II scanner can start picking up throttle/brake position, gear selected, etc...

 

[wildcatgoal]

I see what you're talking about now. Either I was not pushing hard enough (I thought I was going pretty nasty through that area myself, I had similar/same speeds) or I just had enough gas or wasn't gasing it the same as you -- but I didn't experience this. Now I want to go back and try, haha.

 

[NightmareMoon]

Blue, were you running with T/C off?

 

[bluestang50]

Blue, were you running with T/C off?

Yes. I actually had the CEL start flashing when it happened in that video. It stayed on for about 5 seconds and then went off.

 

[ddozier]

Do you guys think there's going to be any long term/catastrophic issues when dealing with fuel starvation or is it just a temporary hiccup and nothing more?

I'm afraid that if you lose fuel pressure and go hard on the throttle that you will go extremely lean and risk doing damage to the pistons? Or does the computer dial back power in order to prevent any damage from lean conditions?

It depends on your setup, NA cars are not likely to have any permanent effects, other than the fuel pump itself does not like to be run without fuel to pump. Boosted cars on the other hand can be very dangerous if fuel pressure and volume are lost while in boost, it usually results in a very lean fuel mixture, followed by knock, followed by piston damage.

Dave

 

[ddozier]

I am very curious to know if any of the GT350/GT350R guys have had any issues with fuel starvation. If not I wonder what design changes were made with their tanks and if they could fit a GT as a permanent fix.

The GT, GT350 and GT350R all have the same part number for the fuel tank, so if we are seeing it they will likely as well.

Dave

 

[bluestang50]

Dang that is disappointing. Ford racing did a GT350/GT350R track day at AMP for owners. I would assume they had to of run into the same problem if not worse unless they kept them topped off all day.

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