KB vacuum

[meanv10]

When my truck is at a stop in drive it only pulls 18in hg but in park it pulls 20ingh
Also it runs lean 16afr right when i press the gas under normal driveing for a second then goes to 14.7(normal) dono if i have a vacuum leak or what. Could it be the cold weather?
Also think it could be my PVC valve, there is oil around the gormit and top of the hose. Any help would be great (my AFR gauge is a wide band auto meter and my vacume is a mecanical auto meter so i know that the are right on if not perfect)

[White Max]

The vacuum sounds about right. You will see a little less vacuum in gear at idle than you will in park at idle due to the difference in rpm.

The A/F ratio deal sounds like it's probably an issue in the tune. What happens at WOT?

-Rod

[Blurry94]

How about some specifics of the vehicle you're refering to.

[meanv10]

03 F350 v10 Kb supercharger, 36lb injectors, Kb boost a pump,Kb switch chip, heat range cooler ngk plugs gaped to 35, no cats, one of those y pipes off ebay, flow master 40 series muffler, and i think that's about it. at wide open it goes right to 10.2 afr at 6 psi and fuel pressure is like 44 to 45 psi, so it fricken rich, when i look out my mirror i can seen a wight cloud of smoke. thanks for the input

[Blurry94]

What is the fuel octane you're using?

[meanv10]

93 premium ONLY

[Blurry94]

It sounds like you're experiencing a tip-in-lean condition, when the A/F ratios go lean after the throttle is pressed.

11.5 is a good number to shoot for for a boosted application. A tuning change can correct both issues.

[meanv10]

Thanks for the advise, is it alright if i drive it this way?

[Blurry94]

You can drive it, but it's not good to wash the cylinder walls down with all that excess fuel @ WOT.

[FTE Herman]

I'm instantly lean too on tip in but only for a fraction of a second until the PCM adjusts.

[meanv10]

ok sounds like mine to, but the 10.2 at WOT am i losing a lot of power from that

[IB Adrian]

Yes... That is, unless it has been tuned to circumvent other issues (like pinging at WOT)

[Blurry94]

I agree with Fred.

I build my programs off a 11.6 A/F ratio with 93 octane and then raise the timing a degree or two at a time (on a dyno). The power gains will keep increasing until you hit a "buffer zone". This is where the motor wont make any more power with added timing. At that point, backing the timing off a degree or two will keep things safe.

Another variable to consider is air charge temps (ACT). The ECU can be programmed to pull timing and/or add fuel when the ACT's get too excessive.

[meanv10]

thanks for the info

[meanv10]

Hey what would happen if i turned the switch on my switch chip form kenne bell if i wasn't running racing fuel( i know its the racing chip and not the tow/ hall chip)