when going WOT on the straight line the car started to hesitate and cutting like its not getting enough fuel. my guess its something with the fuel pump.

also at some WOT runs the fuel pressure gagues started to flactuate from 47 to 52 psi. when I drove the car back to home FP was steady at 52 psi. what could cause this. p.s, at idle the FP gauge sits at 49 psi which is good I think!

any ideas??


oh and a quick vid ; http://www.youtube.com/watch?v=SX0_9ntXh20

 

was your gas tank near empty?

could be the pump was overheating working really hard if there isn't any gas in the tank to help cool the pump

 

I had about half tank when at the track.

 

I went through a big ordeal for the same issue. There are plenty of causes for this, but you may be hitting the rev limiter. Either that or you're running rich at some point in the acceleration. I just spent a lot of money getting the ignition coil replaced, but not sure if that was even necessary (had aftermarket coils replaced with stock ones).

 

Yeah I hit the rev limiter once and the car bogged for like 3-4 secs but went back to normal. my AFR is set at 11.5 and goes down to 10.6 between 5200 and 5600 rpm then back to 11.5 to redline.

 

that maybe the problem right there, bro.. too rich.. you ever even hit 14 at low rev?

 

The gauge in the car read over 1/4 tank at the track, 2 long right hand sweepers, car would loose fuel pressure and go flat!
I filled the tank, this would not happen on a full tank.
Kevin

 

Tell us more about your setup, and engine management system.

 

I'm running the standard APS TT kit and Unichip Q+.

 

Your fuel pressure should be rising 1:1 with boost. Is it doing that?

 

it is rising one to one and drive normally. the cutting happend while at the track and dissapeard since then..

 

ECU could be pulling timing..

 

Sounds like a fuel pick-up/starvation issue. It's not uncommong for this to happen at the road course track following high lateral G turns. The same lateral G-force may also plaque engine oil pick-up leading to possible oil starvation. Keep an eye on both fuel and oil pressure during AND after high speed sweepers.

 

in long sustained corners on the road course and drifting, my car will start to cut out if at a half tank or lower. this is because of the design of the fuel pump bucket, and the saddle bag fuel tank i guess. we combat this in our drift car by adding a second fuel pump that fills the bucket up for the bigger pump that gets fuel to the engine. it works ok, not fantastic though. we should really do some type of small secondary tank between the tank and the engine, as a buffer.

oh, and most people won't have this problem until they go turbo, as the stock fuel bucket in the tank holds enough fuel for the stock injectors and hp.

 

+1

This same issue happened to my car on the track when I was around 1/2 a tank, Filled the car back up ( they sell 100 oct at the track ) and the problem did not occur. Nothing to be worried about just try to track the car with as much fuel as possible.

HTH,

-George
GT Motorsports