2007 Tahoe 5.3l AFM DOD delete thread

[wsteele]

Here is a clip of what my Tech 2 says the MAP says on my engine at idle and as I crack the throttle.

 

[Geotrash]

Here is a clip of what my Tech 2 says the MAP says on my engine at idle and as I crack the throttle.

Hmmmm... I have a Tech2 and can check mine this week and report back, if it would be helpful.

 

[wsteele]

Hmmmm... I have a Tech2 and can check mine this week and report back, if it would be helpful.

Might help square the loop..

 

[wsteele]

I got a chance to watch my MAP numbers on my ODB iPhone Ap while running errands. The idle pressure jumps quite a bit as soon as you drop it into gear, so load makes a very big difference, as opposed to sitting and idling.

I suspect the lowest idle vacuum you might see would be engine idling backing down a driveway (essentially the lowest engine load), other than when you crack the throttle open and things haven't caught up yet, but in that case, you also aren't using the brake.

 

[ShootinHeavies]

Here is a clip of what my Tech 2 says the MAP says on my engine at idle and as I crack the throttle.

This is close to the same we were seeing in the snap on unit, and through the gauge. Under power and above idle the brakes work as normal, but the pedal shudders and brakes are softish backing up. Been talking withe the shop and they are going to go through the tune, and I am purchasing the tuning software to have, but it doesnt seem that the reading we are getting are all that far off from this video.

 

[ShootinHeavies]

Hmmmm... I have a Tech2 and can check mine this week and report back, if it would be helpful.

If possible it would help since we are running the same cam setup.

 

[wsteele]

This is close to the same we were seeing in the snap on unit, and through the gauge. Under power and above idle the brakes work as normal, but the pedal shudders and brakes are softish backing up. Been talking withe the shop and they are going to go through the tune, and I am purchasing the tuning software to have, but it doesnt seem that the reading we are getting are all that far off from this video.

The one I posted was just sitting in my garage at idle. I suspect if you were backing down a driveway, at idle, it would be even lower. It really changes under load and in deceleration coming completely off the throttle but the engine under load (engine braking). so it would jive that you are seeing worst case backing down a driveway.

 

[George B]

Do these boosters still have a check valve?

 

[wsteele]

Do these boosters still have a check valve?

Looks like mine does.

 

[George B]

Looks like mine does.

View attachment 345455

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