2007 Tahoe 5.3l AFM DOD delete thread

[wsteele]

Yup, I was wondering if the OP has a leaky check valve on the booster.

Good idea. There are three *********** into that chamber (Actually 4 if you count the master cylinder), the check valve and two sensors. I wonder how much all that matters when it comes to leak down of the vacuum? Also, if it was just a minor leak, a fresh start before you have any serious engine braking pressures to store vacuum, again would be the worst case for how much assist you are getting.'

One thing that confuses me is the softish pedal and shuddering report. Anytime I have had vacuum boost issues, the pedal gets extremely hard, versus soft. But those are all pre-abs experiences.

Wow, pene-trations is censored.

 

[wsteele]

Here is a better clip of my Yukon at idle with a few throttle blips. I found the "intake data" page in the Tech 2 diagnostics, better than trying to figure out what the barometer is saying today and doing the math by hand...

 

[ShootinHeavies]

Well after messing with this for weeks and basically going over the entire install, buying HP Tuners to play with the tuning, we couldn't get it to quit throwing the service brakes message, so we swapped cams to a TxSpeed stage 2 and retuned. Absolutely no issues with the brakes with the TxSpeed cam. The BTR cam was 111 lsa and the TxSpeed 112 lsa, but no low vacuum issues, not sure if the BTR grind was just off or what, but were saving it for another build with hydro boost brakes anyways. Again, apologies for derailing this thread.

 

[crownvic31]

Good info

 

[NardDog]

Allot answers here, I couldn’t read them all but I didn’t see any mention about the torque angle degrees tool for the head bolts. Maybe it was Idk but dont forget that.