Inj pulse width

[Ridin'GMC]

I'm curious what happens when the injector pulse width is too low at idle area. Also how many mpa does it usually run at idle?

Couldn't find any info about this. I've been experiencing a weird rattle that only happens for 2 second upon initial start up. Been that way for years, never could find why it did that. Various tunes did the same thing as well.

I just feel like I should start from scratch with a stock tune to get it where I want it to be at, although I don't have the stock tune. Been using a mild modified tune from a tuner to make my tunes when I first got my efi.

 

[SSchmi5519]

Watch your oil pressure gauge and see if the rattle sound goes away when the oil pressure pops up.

 

[S Phinney]

If Pw was written too low the computer will pull fuel from a higher mm3. It will take what fuel it needs from elsewhere. Rattle probably isn't related.

 

[Ridin'GMC]

Watch your oil pressure gauge and see if the rattle sound goes away when the oil pressure pops up.

What does that mean if it does go away as it builds pressure? I always get 70-80 psi during cold start up.

 

[SSchmi5519]

Mine does that. Takes about 1.5 seconds to get oil pressure after the truck has been sitting. I figured it was normal. The sound is directly related to the pressure in my case and as soon as I see the gauge pop up it quiets down and runs/sounds like normal.

 

[Ridin'GMC]

Hmm. It's kinda weird because I can actually feel it when it starts up. It does it off and on but most of the time when it has been sitting for over 5 hours.

 

[Yellow Jacket]

What does rail pressure do as it starts? Does it spike up and "overshoot".