Base Fuel Quantity vs. TPS

[Backside180]

I just started doing some playing with my 04.5 LLY truck. I figured a good place to start would be to start increasing the fuel in the Base Fuel Quantity vs. TPS table. I increased the table all the way up to 110 mm^3 (from around 88-90 stock) at 100 pct throttle. Logging data I don't see more than 98 mm^3 at WOT. Any idea what would be limiting me from getting to the 110 I'm commanding?

Thanks

[blued turboed1]

The key is to keep fuel preasure at around 23000 psi. Adding fuel quanity adds fuel preasure. Turning up Injector pulse width reduces fuel preasure and adds quanity. I think?

[Backside180]

The key is to keep fuel preasure at around 23000 psi. Adding fuel quanity adds fuel preasure. Turning up Injector pulse width reduces fuel preasure and adds quanity. I think?

What controls the fuel pressure? I don't see any tables commanding fuel pressure vs. anything?

[blued turboed1]

It is a ballence between fuel quanity,and injector pulse width.

[Backside180]

It is a ballence between fuel quanity,and injector pulse width.

So if I wanted to change the fuel pressure at a given operating condition, how do I do that?

Shouldn't there be a table somewhere commanding fuel pressure vs. engine speed and commanded fuel?

[mrrattle]

the required table to make that adjustment is missing in Hptuner.
you need to adjust the desired fuel rail pressure Vs commanded mm3 Vs Rpm

[newjt2]

its the same as the base pressure in the fuel sys tab... isnt it?

[mrrattle]

well how did i miss that , you are correct the base pressure table is what controls commanded fuel rail pressure. But commanding higher pressure wont yeild more pressure if you have already maxed out the pumps output capacity by keeping injectors open too long.

[vortecfcar]

Guys,

Stay away from pressure increases for now. Look to modify your pulsewidth vs. mm3 table for values above 30mm3. This is the easiest way to get the truck to fuel harder.

[CRASHNBURN]

Thanks for the information & help.

[5_Liter_Eater]

This is some cool stuff. I'm going to have to start lurking around the diesel forums.

[Backside180]

its the same as the base pressure in the fuel sys tab... isnt it?

Can you give me a screen shot of where this table is at in HPTuners or some detailed descriptions? I'm looking at my 2004.5 LLY tune and cannot find this table for "base pressure" that you mention.

Thanks

[Programmer]

There's really no need to modify the rail pressure table, unless you've got better rods, crank, pistons, transmission, turbo, etc....and are trying to exceed 550 WHP...and have deep pockets.

Seriously...