GMC 5.3 Vacuum Pump Failure

[PontiacHO]

Dropped my truck off at the dealership this morning to have the vacuum pump replaced. Supposedly this will be covered by GM. Do these later 5.3 engines not have enough engine vacuum to operate a traditional power brake booster? Maybe it’s the AFM craziness that generates inconsistent vacuum??? About ran through the garage yesterday with a rock hard pedal. Failures of this sort should be nonexistent in modern vehicles. In my opinion…

 

[LazyDog]

What about installing an electric vacuum pump to avoid some of these issues.

 

[PontiacHO]

That may eliminate the engine mounted pump that’s also oil fed by the oil pump. The current pump failure is worrisome especially since the pump may be shedding metal that gets in the engine. Not sure that can happen but it seems logical. The best solution (in my opinion) is operate the booster by engine vacuum like has been done for 70 years. Wondering if the AFM crap creates inconsistent vacuum??

 

[JTK]

What year truck? How many miles?

 

[clinebarger]

That may eliminate the engine mounted pump that’s also oil fed by the oil pump. The current pump failure is worrisome especially since the pump may be shedding metal that gets in the engine. Not sure that can happen but it seems logical. The best solution (in my opinion) is operate the booster by engine vacuum like has been done for 70 years. Wondering if the AFM crap creates inconsistent vacuum??

Yes....The AFM, When active affects engine vacuum. Tuning out the AFM while fix that. Problem is there is no vacuum port on the L83 intakes for a brake booster.

 

[PontiacHO]

What year truck? How many miles?

2017 73k miles. It was covered under the recall.

 

[PontiacHO]

Yes....The AFM, When active affects engine vacuum. Tuning out the AFM while fix that. Problem is there is no vacuum port on the L83 intakes for a brake booster.

I’ve heard about a plug in “dongle” that eliminates that function. Any suggestions. I hate that AFM @*&$!!!

 

[clinebarger]

The Range AFM Disabler works & seems to be reliable, I use tuning software (HP-Tuners) to turn off the AFM in the calibration but it's a little expensive if that's all you're going to do with it.

 

[4WD]

The Range AFM Disabler works & seems to be reliable, I use tuning software (HP-Tuners) to turn off the AFM in the calibration but it's a little expensive if that's all you're going to do with it.

Plugged one in the 2017 5.3 Sept of last year (52k) … drives better for sure … bumped up to 5W30 at 60k …