What fuel Press. Does everyone run..?

jimberg · 08-19-2001, 07:36 AM

Make sure that your TPS is set well below 1 V. Set it to something like .95-.97. If you have it at .99 and you tap on the accelerator the computer will think you're at part throttle when you're still at closed throttle and open the EGR valve and thermactor causing your hesitation. The easiest way to confirm this theory is to disconnect the vacuum line from the EGR and plug it with a golf tee or something. If you still get the hesitation, it is still possible that your EGR valve is stuck open a little, though.

Any changes you make to fuel pressure will require some time for the computer to adapt. How long did you wait between each fuel pressure you tried?

The air/fuel gauges bounce back and forth since that's how the computer works. You're correct that they probably aren't that much help until you're at WOT. Even then it will only indicate whether you are rich or lean but not by how much. The only way to do that would be to get a gauge that works with a wide band o2 sensor. Knowing if you go lean, though, would be some good info.

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351W 89 Mustang GT Convertible

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08-19-2001, 07:36 AM	#9
jimberg Registered Member Join Date: Oct 1998 Location: Rogers, MN Posts: 2,089	Make sure that your TPS is set well below 1 V. Set it to something like .95-.97. If you have it at .99 and you tap on the accelerator the computer will think you're at part throttle when you're still at closed throttle and open the EGR valve and thermactor causing your hesitation. The easiest way to confirm this theory is to disconnect the vacuum line from the EGR and plug it with a golf tee or something. If you still get the hesitation, it is still possible that your EGR valve is stuck open a little, though. Any changes you make to fuel pressure will require some time for the computer to adapt. How long did you wait between each fuel pressure you tried? The air/fuel gauges bounce back and forth since that's how the computer works. You're correct that they probably aren't that much help until you're at WOT. Even then it will only indicate whether you are rich or lean but not by how much. The only way to do that would be to get a gauge that works with a wide band o2 sensor. Knowing if you go lean, though, would be some good info. ------------------ 351W 89 Mustang GT Convertible