Running out of fuel?

[WARBIRD1989]

This is the problem I'm having, when ever I start to make a run 1/4 mile when I get to about 100 mph, my Scanmaster is showing .810 as I begin to keep on the gas it will drop off dramatically all the way down to .600 at this point about four degrees of timing is starting to be pooled out, this was when I had a fuel pressure set at 45 idle 60 wot, I need to increase my fuel pressure all the way up to 60 pounds idle, and close to 90 pounds wot just to stay at 750. could I actually be running out of fuel? I have 42 pound injectors 009. whatever that means I have no idea what 009 references to. The car runs high 11's at 16 pounds of boost, my fuel pump can hold 90 pounds at wide-open throttle, so I do not believe this is a problem. All my sparkplugs seem to be about the same. this car was completely rebuilt roller cam,ported heads,larger throttle body and intake,3800 stall 3.73 gears MSD, trans brake, and so on

 

[Quiky One]

What fuel pump...I bet your stock pump cant feed the heads and cam...

Jason

 

[WARBIRD1989]

After market, it can hold 90 psi all day long, at any rpm.

 

[Quiky One]

How much boost are you running? 15? Idle is 45..Should rise 1 psi of fuel per 1 psi of boost.

Jason

 

[WARBIRD1989]

Max boost is 16 psi. pump gas.

 

[Quiky One]

I wouldnt think your 009 injectors would be running out of fuel that soon. What is your inj. DC?

Jason

 

[WARBIRD1989]

"What is your inj. DC?" What is DC??

 

[Quiky One]

Injector duty cycle. What do you scan with? Scanmaster or direct scan?

Jason

 

[WARBIRD1989]

scanmaster

 

[Quiky One]

Do you have the fast update patch in your chip that does double the speed and shows pulse width and spark advance? If not then forget the DC.

Jason

 

[WARBIRD1989]

No But that sounds like a nice thing to have, who can do that for me?

 

[Quiky One]

What chip do you have? Eric can burn it to his chips and Bob Bailey can do it to his.

Jason

 

[WARBIRD1989]

i just order 6 Siemens (Mototron) Deka 4 Injector 60b/hr and a new chip from turbotweaks, i think i am just runing out of fuel. if this dont work its time for a WRX j/k, I will never go to the Darkside..

 

[Razor]

MAF controls injector duty cycle as well. If your MAF only goes to 150 at WOT.. your going to lean out hard.

If your chip was burned for 16 PSI and you run 25 PSI.. then your going to be out of fuel as well.

If you have Direct Scan you can read injector duty cycle.

I have an issue a month ago I was losing fuel pressure.. ended up being a bad fuel pump relay.

So if your fuel pressure tracks PSI per PSI.. then its injectors not being told to open. MAF or Chip issue.

HTH

 

[WARBIRD1989]

MAF controls injector duty cycle as well. If your MAF only goes to 150 at WOT.. your going to lean out hard.

If your chip was burned for 16 PSI and you run 25 PSI.. then your going to be out of fuel as well.

If you have Direct Scan you can read injector duty cycle.

I have an issue a month ago I was losing fuel pressure.. ended up being a bad fuel pump relay.

So if your fuel pressure tracks PSI per PSI.. then its injectors not being told to open. MAF or Chip issue.

HTH

What should my MAF be at WOT? IF 150 is to low whats good??

 

[Quiky One]

Should max at 250 or 255 at full boost...All depends on the heads and turbo. Some can max out at 10 psi and others with stock heads at 20 psi. If you run the stock MAF, you should definately peg the MAF. The translator will be different as the numbers are cut in half.

Jason

 

[Razor]

At 16 PSI on a stock motor should get you ~255

If you get 150.. thats your problem.