I am toying with my fuel pressure and due to a custom chip we have been experimenting with have found that my car was leaning out under high rpm WOT situations. IE 3rd gear redline, and 4th gear between 4 and 6000 rpms.

I am running 19# injectors but we have dropped the fuel curve way back on the chip. With the stock chip I was needing to run the fuel pressure down in the mid to low 30's idle and low 40's at WOT to keep it from running pig rich.

I wanted to raise the fuel pressure up for better atomization so we started dropping the base pulse width on the injectors 5% at a time, the first 10% made very little diffrence, the last 5% holy cowabunga batman. Around town it is perfect, during the day on the highway it is perfect, but on late night runs, where the air is cooler, and you are making an extended high speed run down the freeway at WOT my air fuel gauge is showing it to drop out of the rich area on the gauge. (no I dont trust the gauges to be exact, I use them like a Green light Red Light. It is not staying fully in the green at WOT) I was thinking about bumping it up a bit further, but I remember reading someplace that the Fiero injectors had a tendency to lock at any pressure close to 60psi.

Does anyone have any suggestions on this. PS I am not ditching the 19# injectors becuase we are going to make up a race only eprom for my car to use with the nitrous. Have all the engine, timming and fuel tweaks done in the prom so when it is time to race it will be a matter of popping out one chip and popping in the other.

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85GT 2.9 4spd MSD Everything, Big Cam and Nitrous. www.captfiero.com

I've run about 40 psi of fuel pressure at idle which results in about 48 -50 psi at WOT . My 3.4L has been working on this fuel pressure for quite some time without any problems.

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87GT 3.4 Turbo Best 0-60 5.2 seconds
http://www.turbochargerpower.com/turbo.htm

Thanks Dennis. It relaxes me a bit. I am running the holly adjustable fuel pressure regulator wich seems to be giving me about 11-12lbs between vacuum and non vacuum conditions.

I might add that I would not go above 50 psi fuel pressure. My fuel pressure is set high for a reason; to compensate for boost. At 50 psi of fuel pressure and 10 psi of boost, you have ten pounds of pressure pushing back on the injector flow. This nets an actual fuel pressure spray of 40 psi ( les the compensation effect from the regulator. Many Turbochaged engine owners do not realize that the higher the boost, the lower the fuel pressure. As I've pointed out, while the fstock style uel pressure regulator will compensate for some of the boost, you will still lose fuel pressure with a turbo. That is why I adjsut the pressure a few pounds higher.

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87GT 3.4 Turbo Best 0-60 5.2 seconds
http://www.turbochargerpower.com/turbo.htm