Serious Fuel Supply Issue
6/20/11, 12:45 PM
#61
Member
Thread Starter
Join Date: June 13, 2011
Location: Calgary
Posts: 26
Likes: 0
Received 0 Likes
on
0 Posts
Hey Dale, just got back from BIR this weekend so this is the first I've seen on this thread. I've got 6 track days in the Boss now and all have been pushing pretty hard. I haven't encountered this issue. We have always run the track clockwise so more rights than lefts, but still have several either tight left handers or long sweeping ones. In fact there's a 180 between two straights on one of the tracks that I've run two days now and I would think the issue would have surfaced there. I've always been leery of fuel levels in both the GT500 and the Boss (same tank far as I can tell). With the supercharged GT500 I was really worried about running lean so I tended to keep the fuel level high at the track. I never run below 1/4 even on the street. I usually start my sessions in the Boss around 3/4 and the lowest I've ever gotten was 1/4. However, I usually only run it full during the first session since I trailer to the track with a full tank. Likewise I bring 5 five gal gas cans to the track with me so I can fill there and refill the cans in the evening.
This weekend I did not encounter the random misfire issue. The curbing/rumble strips for the most part are smooth at BIR though. I was banging them routinely so that seems to validate engineering's finding that the P0300 is caused by vibrations transmitted through the drivetrain to the crankshaft.
As far as our tanks go on the S197, there has been a consistent issue with fill ups. I have to hold the nozzle at 90 degrees and only insert about halfway when filling up the GT500. I can only go to the first click on the pump handle as well or it will vapor lock and shoot fuel out clicking off the pump. The Boss seems to fill a little better, but I still only go to the first click. There seems to be an issue with the flow on how the fill tube has to be routed through the chassis. I'll be watching this thread with interest though.
This weekend I did not encounter the random misfire issue. The curbing/rumble strips for the most part are smooth at BIR though. I was banging them routinely so that seems to validate engineering's finding that the P0300 is caused by vibrations transmitted through the drivetrain to the crankshaft.
As far as our tanks go on the S197, there has been a consistent issue with fill ups. I have to hold the nozzle at 90 degrees and only insert about halfway when filling up the GT500. I can only go to the first click on the pump handle as well or it will vapor lock and shoot fuel out clicking off the pump. The Boss seems to fill a little better, but I still only go to the first click. There seems to be an issue with the flow on how the fill tube has to be routed through the chassis. I'll be watching this thread with interest though.
Thanks for your reply. I figured you were probably away this weekend. I am happy that you didn't have any random misfire issues. I have never had this problem yet and one of the tracks I run on is extremely rough.
I have no problems filling my Boss. Here in Canada all of the self-service gas stations have removed the little metal tab that allows continuous flow to the nozzle. I built a little wooden block that has mutiple increments on it to shove under the trigger and it works great.
I think the problem I am experiencing is very track specific. My local track I have no problems. If I can figure out how to post a video I will try and give you an idea of how tight the track is where I experienced the problem. I have videos from other people that weekend but I would like to try and post my own.
6/20/11, 01:00 PM
#62
Member
Thread Starter
Join Date: June 13, 2011
Location: Calgary
Posts: 26
Likes: 0
Received 0 Likes
on
0 Posts
Thanks for the videos. Where are the other people on the track? It must be nice to have the track to yourself!
Unfortunately that track is nothing like the one where I experienced my problem. I didn't see any tight left handers. I heard tire squeel occassionally so I know you are pushing the car hard. I like some of the flowing sections of that track. I am so limited up here in Canada where I can run my car within reasonable driving distance. I am definitely jealous.
6/20/11, 01:08 PM
#63
Member
Thread Starter
Join Date: June 13, 2011
Location: Calgary
Posts: 26
Likes: 0
Received 0 Likes
on
0 Posts
Just curious, when you say "traction control", do you mean stability control also. They are both different. Stability control will also take power away from the engine. To shut both off you have to hold the TC button down for 5 second while holding down the brake pedal. Lets hope its not a fuel delivery problem... I would hate to have to show my dealer when it acts up!
I am not overly concerned at this point. I just now know if I go to this track I need to bring fuel and to top-up between sessions. I am just really curious to see if any other Boss owners out there have seen this issue.
6/20/11, 04:07 PM
#64
Not sure what to say on that. Given that I had the issue on four separate occasions and Dave did as well, along with the response from engineering tells me it's an issue in the tune that they must be aware of. I'm not too worried about it, but something that will need to get fixed. Of course the best fix for it is TracKey 
Unfortunately that track is nothing like the one where I experienced my problem. I didn't see any tight left handers. I heard tire squeel occassionally so I know you are pushing the car hard. I like some of the flowing sections of that track. I am so limited up here in Canada where I can run my car within reasonable driving distance. I am definitely jealous.
It is nice, I have 4 tracks within 2-3 hours from here, three of them world class like Daytona.
6/21/11, 06:37 AM
#65
Member
Join Date: May 18, 2011
Posts: 48
Likes: 0
Received 0 Likes
on
0 Posts
I ran the BOSS at an auto cross event where I ran the fuel level down to the car had to warn me 50 miles to E. I never had any fuel issues which surprised me. And the layout did have a section where you turned left for almost a whole 360 degrees at speed. Very fun layout and got many compliments on the BOSS.
6/24/11, 08:53 PM
#66
GT Member
Join Date: February 16, 2011
Location: Orlando
Posts: 129
Likes: 0
Received 0 Likes
on
0 Posts
ideas,
weak fuel pump can cause a misfire in a heart beat, but.
is it possible you got some less than good fuel?
weak pump and clogged injector. i know it is not supposed to happen, but it does..
beers
weak fuel pump can cause a misfire in a heart beat, but.
is it possible you got some less than good fuel?
weak pump and clogged injector. i know it is not supposed to happen, but it does..
beers
6/24/11, 09:42 PM
#67
6/24/11, 10:00 PM
#68
GT Member
Join Date: February 16, 2011
Location: Orlando
Posts: 129
Likes: 0
Received 0 Likes
on
0 Posts
6/25/11, 12:26 AM
#69
Originally Posted by 2012YellowBoss
Impossible, the government has spent billions of our tax money on the great ethanol experiment
6/25/11, 05:08 AM
#70
Originally Posted by Swoope
he is in canada! i would bet the fuel there is better / consistent that the down under! LOL
beers
6/25/11, 05:12 AM
#71
Mach 1 Member
Originally Posted by phiggs54
Corn is supposed to go in your stomach, not your hi-performance IC engine. If the government wanted us to put it in our fuel, they should not have made the gasoline filler openining smaller than a corn cob.
7/4/11, 05:09 PM
#72
Any more news/info on this?
7/5/11, 01:00 PM
#73
Member
Join Date: September 16, 2008
Location: Colorado
Posts: 43
Likes: 0
Received 0 Likes
on
0 Posts
Interesting thread.
I posted this as part of another thread: Only issue I had was throughout Sunday in one particular hard left-hand corner, coming out of it hard in 3rd gear, over a very slight imperfection in the track, the car seemed to have a brief fuel delivery hiccup. As the day's air temps got hotter, the single "burp" became 3 or 4, almost like a defueling issue - I could drive through it by going a little easier on the throttle, but it was definitely slowing me down on the infield portion of the track. Wondering if there was an issue with the fuel in the driver side of the tank, the pickup, etc. So we're going to try to trouble shoot that this week. Nowhere else on the track did I have that issue, and was able to mash the pedal all the way to redline everywhere else on the track and through hard right turns.
Did not have this issue on Saturday, but didn't really start getting in the groove until the final session on Saturday, and was down at just over a half tank then. However, I'm pretty sure I wasn't pushing the car as hard coming out of that particular corner because I didn't have as good a line as I did on Sunday. Sunday was when I adjusted my line in that corner so that I could mash the throttle as soon as I turned in at the Apex, thus significantly increasing my speed. In addition, I came out of a series of 4 good, fast right & left twisties immediately prior to hitting that hard left corner.
The harder I pushed out of that left turn and was tracking out to the outside edge of the track in the straight portion, the worse the "hiccups" got. Prior to running on Sunday, I added another 5 gallons to the tank, and the problems started showing up with right around 3/4 tank.
Car is an '07 Shelby GT, 4.6L, naturally aspirated. It was a similar situation to the defueling that I experienced once when I went too far into redline before upshifting, but it definitely felt like a fuel starvation situation. I could not re-create the issue at any other point on the track. Ambient air temps were at 96*. Traction control was turned off. No SES light.
I posted this as part of another thread: Only issue I had was throughout Sunday in one particular hard left-hand corner, coming out of it hard in 3rd gear, over a very slight imperfection in the track, the car seemed to have a brief fuel delivery hiccup. As the day's air temps got hotter, the single "burp" became 3 or 4, almost like a defueling issue - I could drive through it by going a little easier on the throttle, but it was definitely slowing me down on the infield portion of the track. Wondering if there was an issue with the fuel in the driver side of the tank, the pickup, etc. So we're going to try to trouble shoot that this week. Nowhere else on the track did I have that issue, and was able to mash the pedal all the way to redline everywhere else on the track and through hard right turns.
Did not have this issue on Saturday, but didn't really start getting in the groove until the final session on Saturday, and was down at just over a half tank then. However, I'm pretty sure I wasn't pushing the car as hard coming out of that particular corner because I didn't have as good a line as I did on Sunday. Sunday was when I adjusted my line in that corner so that I could mash the throttle as soon as I turned in at the Apex, thus significantly increasing my speed. In addition, I came out of a series of 4 good, fast right & left twisties immediately prior to hitting that hard left corner.
The harder I pushed out of that left turn and was tracking out to the outside edge of the track in the straight portion, the worse the "hiccups" got. Prior to running on Sunday, I added another 5 gallons to the tank, and the problems started showing up with right around 3/4 tank.
Car is an '07 Shelby GT, 4.6L, naturally aspirated. It was a similar situation to the defueling that I experienced once when I went too far into redline before upshifting, but it definitely felt like a fuel starvation situation. I could not re-create the issue at any other point on the track. Ambient air temps were at 96*. Traction control was turned off. No SES light.
Last edited by bandit67; 7/5/11 at 03:54 PM.
7/5/11, 03:49 PM
#75
Bullitt Member
Join Date: April 21, 2011
Location: Santa Clarita, CA
Posts: 482
Likes: 0
Received 0 Likes
on
0 Posts
I still can't see the car truly missing from fuel starvation and not throwing a code. As I said, this is a relatively easy event to capture and report on as well as quite serious. It would seem that the ECU can/should catch this.
This leads me to believe it's something else - perhaps something the ECU is intentionally doing due to a bad input. Earlier someone mentioned that the knock sensors could be misled by some sort of chassis anomoly - so perhaps something like this.
I agree that fuel starvation would explain the symptoms but just don't seem to think a misfire/hesitation event could go uncaptured. If true, then we are realing dealing with two problems which just seems unlikely IMHO.
This leads me to believe it's something else - perhaps something the ECU is intentionally doing due to a bad input. Earlier someone mentioned that the knock sensors could be misled by some sort of chassis anomoly - so perhaps something like this.
I agree that fuel starvation would explain the symptoms but just don't seem to think a misfire/hesitation event could go uncaptured. If true, then we are realing dealing with two problems which just seems unlikely IMHO.
7/5/11, 04:02 PM
#76
I still can't see the car truly missing from fuel starvation and not throwing a code. As I said, this is a relatively easy event to capture and report on as well as quite serious. It would seem that the ECU can/should catch this.
This leads me to believe it's something else - perhaps something the ECU is intentionally doing due to a bad input. Earlier someone mentioned that the knock sensors could be misled by some sort of chassis anomoly - so perhaps something like this.
I agree that fuel starvation would explain the symptoms but just don't seem to think a misfire/hesitation event could go uncaptured. If true, then we are realing dealing with two problems which just seems unlikely IMHO.
This leads me to believe it's something else - perhaps something the ECU is intentionally doing due to a bad input. Earlier someone mentioned that the knock sensors could be misled by some sort of chassis anomoly - so perhaps something like this.
I agree that fuel starvation would explain the symptoms but just don't seem to think a misfire/hesitation event could go uncaptured. If true, then we are realing dealing with two problems which just seems unlikely IMHO.
7/5/11, 04:18 PM
#77
Member
Join Date: September 16, 2008
Location: Colorado
Posts: 43
Likes: 0
Received 0 Likes
on
0 Posts
I didn't get an SES light. I've also been told that the computer may not have even gotten a snapshot of the event so we can download it later or pull a code. Based on my '01 Powerstroke, the computer did throw codes without throwing the SES light, so I assume the same can occur in the Mustang.
First thing we'll check is for any codes that may have been thrown. If we can't find any evidence of the event, then we'll hook up a laptop to take real time readings and I'll ATTEMPT to re-create the situation, but that may even prove difficult.
I guess at least we seem to think one possible band-aid fix is to keep the fuel tank full while on track, but I'm still going to try to come up with a better solution once we can come up with some sort of diagnosis.
First thing we'll check is for any codes that may have been thrown. If we can't find any evidence of the event, then we'll hook up a laptop to take real time readings and I'll ATTEMPT to re-create the situation, but that may even prove difficult.
I guess at least we seem to think one possible band-aid fix is to keep the fuel tank full while on track, but I'm still going to try to come up with a better solution once we can come up with some sort of diagnosis.
7/5/11, 04:21 PM
#78
Bullitt Member
Join Date: April 21, 2011
Location: Santa Clarita, CA
Posts: 482
Likes: 0
Received 0 Likes
on
0 Posts
not so sure on this, if it was something like a knock sensor it would throw a code for sure. I am not certain how fuel starvation acts on the ECU, if you run out of gas does it throw a code? I do not know since I never have but never heard of someone getting a code from running out of gas.
My example regarding the knock sensor was that if the car *erroneously* thinks it's pinging (because the knock sensor picked up something from the chassis) then it could yank timing in response to this. In this scenario, the ECU is in control and thinks it's doing the right thing - so no fault code.
But the OP reported a very distinct out-of-fuel-like stutter which really can't be attributed to a timing pull. My bet (guess) is some erroneous way that the traction control is causing this when clearly it shouldn't be while in the off mode.
7/5/11, 05:10 PM
#79
Cobra Member
Join Date: August 5, 2008
Location: Arvada, CO
Posts: 1,369
Likes: 0
Received 0 Likes
on
0 Posts
I assume the fuel pump will throw a code if it's load suddenly changes, ie sucking air, or the O2 sensors will notice the change in burnt emissions, but what else is there that's detecting if the supposed correct amount of fuel going in suddenly has a hiccup?
7/5/11, 05:31 PM
#80
Bullitt Member
Join Date: April 21, 2011
Location: Santa Clarita, CA
Posts: 482
Likes: 0
Received 0 Likes
on
0 Posts
All good questions, and you are right that I don't know all of the details behind how it captures. You bring up an interesting point - maybe it can only detect misfire from lack of spark?? However, with enough misfires to stumble the car, I'd think that a lean condition should be detectable from the O2's. Perhaps the ECU tolerance level is not exceeded, however, and the stumble gets back on track before the ECU gets angry. This is the tolerance you are speaking of when removing the intake tube. No fault code may be generated but if you were to try to drive like that you wouldn't get very far before a fault code. (I've noticed this when we forgot to re-connect the MAF sensor connector.)
The most convincing evidence of fuel starvation is the fact that the problem doesn't occur if kept above 3/4 full. I am simply trying to broaden the thinking to see if it could be something else - hopefully a simplier/easier fix.
The most convincing evidence of fuel starvation is the fact that the problem doesn't occur if kept above 3/4 full. I am simply trying to broaden the thinking to see if it could be something else - hopefully a simplier/easier fix.