how to get 5.0 fuel mixture perfect!!

Allforspeed

New Member
Oct 25, 2004
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i wish i knew!
i just got an Adjustable fuel pressure regulator and guage and now i'm hearing that it will allow control over the fuel pressure for about 1 hour until the ECU figures it out and changes the pulsewidth to adjust the air fuel ratio back to stock??!!
is this true, did i just waste $$$ on something shiny?
i have also now heard that stock fuel pressure setting is best anyway?!
i have also noticed that when the car is running and i move the TPS sensor the fuel mixture changes, maybe the TPS sensor can be moved to trick the car into thinking the throttle is more open to increase fuel?? i dunno... i just hope someone here has some pointers on how to tune a mustang 5.0 with mass air without re burnin an ecu or changing sample tubes and injectors as i still run stock injectors till i reach around 300 hp or so, but am planning on running a 100 shot this summer after new headgaskets is an AFPR even needed?

any pointers? anyone want to buy a mallory FPR and guage for cheap
 
yep, you are right about the adaptive nature of the computer. often guys disconnect the battery between runs to get the pulsewidth widened back up (remember it learns during open loop too).

FPR is not a waste, but not as big a deal as some would think.

they do make a plug in that accelerates the TPS signal (so it reads higher), but my take is that if one simply buries the foot further in the pedal, the results are the same.

when it comes to choosing FP, i would go backwards from the duty cycle of the injectors - i like to run ~95%.

im not nearly as good as many on this stuff; im sure others will chime in.
good luck.
 
The only way I know of to get the AFR perfect is through an EEC editing program, and a wideband O2 sensor. All of which I have, and it is still no walk in the park. (you gotta spend a lot of time tuning)

You're right on the uselessness of an AFPR unless you're doing some serious fuel pressure changes.
 
dont take out the regulator! you just gotta play with it a little bit. the computer cannot make changes to the fuel pressure, only the pulse width of the injectors; especially since the only things that alter the fuel pressure is the vacuum signal and the adjusting screw in the regulator! with more pressure the computer narrows the pulsewidth to meter the same amount of fuel at the same event in the engine cycle... the reason for installing a regulator in the first place is to be able to increase the line pressure to force more fuel through the injectors per unit time, which allows you to use the stock injectors at highter HP levels... just sit back and think about it. you'll get it.