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near graduate!
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Discussion Starter · #1 ·
What does the injector size do to the engine management system?

Does a 45# injector require a longer pulse width (time the injector is open if I'm using the wrong terminology) than a 60# injector to deliver the same amount of fuel?

And do you need to run 60# of fuel line pressure to run a 60# injector properly.. or with they run fine under 50# of line pressure?

As always, thanks for all the help!
 

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Yes, a 45 will need a longer pulse width than a 60 but this is normally done by calibrating the mass air meter to trick the computer into having the right pulse width.

Normally you keep the fuel pressure at the stock 38-40 psi.

You could also reprogram the computer to adjust the pulse width using a mass air meter calibrated for a different injector but that would be a more complicated/specialized fix.

Cheers, Rod
 

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near graduate!
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Discussion Starter · #3 ·
Perfect!

The 2005 4.6 uses 60# injectors, but the Redline system I am using was originally set up for the 2004.. and it's just NOT running right. So this will help a bit I hope. Thanks for the help.
 

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Recalibrating the MAF sensor will compensate for the injector change, but throws off the power calculations the EEC uses for other functions.
 
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