Do I have a fuel issue??? 2005 GT

[cop on my back]

So I went to the local track and for the first time ran the oval. There were only 4 of us and we rented the track for 2 hrs. I have done lots of autocross and some road course racing, never oval.

I started with a full tank and when I got down to 3/4 full the car would start to sputter coming out of the corners at WOT. Once I got down to 2/3 of a tank the car would outright fall on its face out of the corner.

Details, pretty much stock motor with a CAI and a 93 octane tune. Side exhaust and that is in for the motor, the rest is in the suspension and brakes. 2005 GT with about 45k on the clock, 5sp.

Coming out of the corners, the car would be around 4500 rpm up to about 6000 when I hit the brakes in second gear.


The car now will not go over 5500 in a straight line at WOT, it sputters and pops, farts, you name it. I am afraid it is going lean due to a bad fuel pump.
The video is a bit boring, as you would expect for oval track racing, but at the 5:20 mark I decide to follow a drifter and it is a good view of him sliding everywhere. I am in 3rd gear for the first bit and then downshift to second gear to go faster, that is when the full issue happens.

Video looks better full screen, it is in HD.
Ideas?

 

[stkjock]

When did u last change the fuel filter?

 

[cop on my back]

Changed it about 12k ago. It ran fine with a full tank but got worse as the tank slowly emptied. Never had a problem in a straight line until now after today's event.

 

[EGNARO]

sub'd curious to see the cause of this

 

[cop on my back]

I am likely going to pull the fuel pump seeing as it is easy to get at. I have to wait until my back up ride has the transmission swapped which will take a few more days.

 

[Vapour Trails]

There is a fuel pump TSB for the early cars which causes bucking but that is generally after a long cruise. I had mine replaced many years ago (stock pump that is).

I would just pull the pumps (both sides) and inspect them.

 

[cop on my back]

There are 2 pumps? I didn't even know that. I know there is a saddle tank, but not 2 pumps. I am glad I discovered this problem now and not on my trip to Seattle to run the track at Pacific Raceways, that would have sucked.

 

[JeremyH]

No there arent 2 pumps, just the one on the drivers side. I agree sounds like it could be the 05/06 fuel pump tsb issue. I have some stock 07+ fuel pumps if you need one to swap out let me know.

 

[cop on my back]

No there arent 2 pumps, just the one on the drivers side. I agree sounds like it could be the 05/06 fuel pump tsb issue. I have some stock 07+ fuel pumps if you need one to swap out let me know.

Good to know, I may come a knocking.

 

[Vapour Trails]

The passenger side pump is a jet pump, so it is not the same as the driver's side, but I still refer to it as pump. I would still open that side and inspect. Doing hard left handed turns repeatedly is going to cause fuel to slosh to the passenger side tank. That doesn't explain why you have problems even in a straight line now but strange things can happen. I had my fuel gauge get stuck on "Full" after an autoX event. The float arm on the passenger side was stuck. There's always a chance something got disconnected.

 

[JeremyH]

Don't try to confuse people, just say siphon lol. I agree doesnt hurt to check that side, if the electrical pump is going bad and loosing pressure/cavitating that can cause a loss in the overall venturi effect on the passenger side and it may not be pulling fuel over and emptying all the way like it should.

 

[JesseW.]

my car is having this problem after left hand turns at autocross, doesn't matter if the tank is 3/4 full or 1/4 full. subbing.

 

[cop on my back]

my car is having this problem after left hand turns at autocross, doesn't matter if the tank is 3/4 full or 1/4 full. subbing.

Mine started in in autocross last year, but not all the time. Funny thing, today I drove it to work and reved it up in 2nd gear and it pulled all the way to the limiter no problems. Gotta love these types of problems. I am guessing heat played a part.

 

[cop on my back]

I will be changing out the fuel pump with a newer one. The only problem is the only time it was screwing up was after constant WOT, something I can't exactly do on the streets. I will have to get to an autocross event and give it a go.

I have not pulled the old pump out yet, but from the TSB and what I have been getting I think it is safe to assume this is the problem.

 

[arabbit]

Hey I've had that bucking after a long cruise on multiple occasions...I will be checking mine as well! Never even knew about the TSB.

Edit: Haven't tried autocross yet, glad I read this first. If it happens to me, I will know the cause.

 

[JeremyH]

my car is having this problem after left hand turns at autocross, doesn't matter if the tank is 3/4 full or 1/4 full. subbing.

What year car?

Hey I've had that bucking after a long cruise on multiple occasions...I will be checking mine as well! Never even knew about the TSB.

Edit: Haven't tried autocross yet, glad I read this first. If it happens to me, I will know the cause.

Got a late december 07 fuel pump headed to the op on monday, lets see how it does!

BTW here is the link to the TSB if you havent read it yet.

http://www.s197forum.com/forum/showpost.php?p=218817&postcount=79

 

[Racingtheburg]

SOUNDS EXACTLY like mine did with bad fuel. Check your plugs make sure your not eating them like my car was due to running lean. So far from what I've changed out I found the culprit to be bad fuel/ + additives in shell 93 gas clogged my fuel filter, fuel rail, and injectors. Also lost one plug completely.

My thread: http://s197forum.com/forum/showthread.php?t=81235

 

[JesseW.]

What year car?





Got a late december 07 fuel pump headed to the op on monday, lets see how it does!

BTW here is the link to the TSB if you havent read it yet.

http://www.s197forum.com/forum/showpost.php?p=218817&postcount=79

Mine is an 05 as well. if it fixes his i may as well order one. mine has the "vortech piggyback pump" (walbro 255 i think) on it as well as i am supercharged, but i've had this same issue at autocross only for about 2 years now. i've changed plugs, COP's, boost bypass valve, supercharger belt, run on full tanks of gas and it still does it after left turns going to wide open throttle....

 

[cop on my back]

Pulled plugs today and they are just fine. They came out easy too with the antisieze I put on some time ago. Changing the fuel pump next.

 

[cop on my back]

Installed pump tonight, what a PITA. Well not really that bad, but the gas fumes had me high as a kite by the time I got the pump back in.

Now I just need to hit the track or a back road and go WOT for a while.