Has anyone done this GM vacuum pump delete?

mookdoc6 · October 27, 2020

25 minutes ago, rav3 said:

Where is the "micro screen" that you referenced? in the PUMP? I have searched several GM online parts sources and most come back: "ON back order". this is the P/N i've searched for: GM GENUINE 12696313. Is there a newer version of this one? I noticed that GM just did a recent recall on the 2018 trucks for the "hard brake issue". October 1, 2020 NHTSA CAMPAIGN NUMBER: 20V603000

on the pump inlet side from crankcase. I am not sure about p/n I do not have records with me. I do know it was revised again just a month or two ago? I had difficulty procuring the new p/n but that was because nobody knew what was going on and AC DELCO stopped shipping on it?

Grumpy Bear · October 27, 2020

37 minutes ago, M1ck3y said:

I'm not doubting guys, just trying to get a picture of how the brake booster works, along with the pcv system. And what's affected, if anything by introducing the brake booster to the pcv system.

I understand your confusion now.

On the Ecotec3 Gen 5 motors a vacuum pump is crankshaft driven via belt to draw vacuum on the brake booster. When the fella that made the video removed his pump he plumbed the booster to the inlet manifold like they USE TO BE before AFM.

The pump is required when the AFM is active (read this quote below)

1 hour ago, rav3 said:

Well, with the EPA pressure for more MPG & fewer emissions, they are forced to find ways to meet these requirement. Hence, the AFM on K2XX models & DFM on the new Silverado's. These engines don't produce enough manifold vacuum to keep the brake booster up to where it needs to be, so to solve that issue, GM added the infamous vacuum pump. Thank the EPA for this. It saves fuel up front but passes that cost on to the consumer via more frequent repairs.

What got missed is, "When in V-4 Mode". Got it?

Okay so when this fella in the video moved the vacuum source to the manifold he also had to delete the AFM to keep the vacuum high enough to boost the brakes.

Edited October 27, 2020 by Grumpy Bear

M1ck3y · October 27, 2020

Well... So he said he deleted the pcv line that goes directly to the manifold, and the booster is hooked up to the drivers side valve cover. So there's one pcv line that can run to the intake tube on one side only, before the throttle body... Is that enough? I mean I thought the two valve cover breathers were just that, breathers. They help equalize the pressure or something, where as the pcv line to the manifold actually expels the vapor/liquid. With the valve covers having a similar purpose of a catch can.

And besides that, he capped off the other valve cover. This whole time I've been thinking the vacuum pump actually created negative pressure in the crankcase... lol

Edited October 27, 2020 by M1ck3y

M1ck3y · October 27, 2020

Ok this answers a few things.

https://www.gm-trucks.com/forums/topic/230820-how-to-delete-brake-vacuum-pump-video/

I can't pretend that I know exactly how the pcv system works but I dont agree with him saying the majority of the vapor/gas/oil comes through the valve covers and into the air intake tube.

I've had my throttle body off to clean. Intake tube was spotless and the front of the throttle body had very little oil on it. The backside was coated in oil as well as the inside of the intake manifold.

rav3 · October 27, 2020

29 minutes ago, M1ck3y said:

Ok this answers a few things.

https://www.gm-trucks.com/forums/topic/230820-how-to-delete-brake-vacuum-pump-video/

I can't pretend that I know exactly how the pcv system works but I dont agree with him saying the majority of the vapor/gas/oil comes through the valve covers and into the air intake tube.

I've had my throttle body off to clean. Intake tube was spotless and the front of the throttle body had very little oil on it. The backside was coated in oil as well as the inside of the intake manifold.

M1 how many miles on your truck

M1ck3y · October 27, 2020

15 minutes ago, rav3 said:

M1 how many miles on your truck

40000 kms. No idling, but I do drive hard frequently. It was probably at 30000 kms when I checked it.

M1ck3y · October 27, 2020

I want to figure out how to do an electric brake booster and use the belt driven vacuum pump on the crankcase. Anyone done this?

rav3 · October 27, 2020

3 minutes ago, M1ck3y said:

40000 kms. No idling, but I do drive hard frequently. It was probably at 30000 kms when I checked it.

That's not many miles (18k to 24k) I wouldn't expect much if any build up on TB.

rav3 · October 27, 2020

3 minutes ago, M1ck3y said:

I want to figure out how to do an electric brake booster and use the belt driven vacuum pump on the crankcase. Anyone done this?

You should start a new thread for that conversion.