Doing a vac leak smoke test, should the brake booster vacuum pump be blowing smoke out?

[jeffmills69]

For future reference if anyone has the same question:

Connected a probe from the jump posts and into the plug (red wire positive, white wire negative), removed vacuum hose from brake booster as I couldn't get the plug off the pump and confirmed vacuum from brake booster hose and air blowing out from where the smoke was coming out so unless it intermittently stops working while the engine is running then my pump was working correctly when smoke was blowing out

 

[Fu Manchu]

Not on the booster. It's Australian road regulation that the booster must retain vaccume and have 3 vacuume assisted stops left in it when the engine is off.

The booster has a plain old check valve. Not a Positive Crankcase Ventliation valve.

Op most likely has disconnected the booster vacuum hose from the brake booster, leaving the brake booster check valve in the booster.

That’s not what we are talking about here though. On LFW motors there is a vacuum pump, which creates additional vacuum in certain conditions. That is controlled by the ECM and that is what has the smoke coming out.

Thinking about it, the pump would have to have an exhaust port of some sort to expel air in creating a vacuum. Maybe coming the other way from the brake booster, it’s just finding that?

OP needs to bypass or isolate the vacuum pump.

 

[shane_3800]

The booster has a plain old check valve. Not a Positive Crankcase Ventliation valve.

Op most likely has disconnected the booster vacuum hose from the brake booster, leaving the brake booster check valve in the booster.

That’s not what we are talking about here though. On LFW motors there is a vacuum pump, which creates additional vacuum in certain conditions. That is controlled by the ECM and that is what has the smoke coming out.

Thinking about it, the pump would have to have an exhaust port of some sort to expel air in creating a vacuum. Maybe coming the other way from the brake booster, it’s just finding that?

OP needs to bypass or isolate the vacuum pump.

I though the OP was talking about smoke coming out the brake booster......

 

[jeffmills69]

Yeah so it does need to expel air to create a vacuum and the air it pulls is from the hose that connects it to the booster and crankcase, so the little tube that the smoke was coming out of is where it expels air so smoke coming out was it working as its supposed to and because its constantly creating vacuum when the cars running it doesn't cause a vac leak

I was using the hose I disconnected from the brake booster and it was coming out of the brake booster vacuum pump

 

[Fu Manchu]

When I was digging around about the vacuum pump, it mentioned it should only run under certain conditions and that was controlled by the ECM.

So if you had a vacuum leak somewhere then the pump will always run because of low vacuum.

I’ll try dig the info out later for you.

It might or might not help?

 

[jeffmills69]

When I was digging around about the vacuum pump, it mentioned it should only run under certain conditions and that was controlled by the ECM.

So if you had a vacuum leak somewhere then the pump will always run because of low vacuum.

I’ll try dig the info out later for you.

It might or might not help?

Might be some help, cheers

 

[Fu Manchu]

Maybe take a look at the pressure sensor. It's near the brake fluid reservoir. If it's reading incorrect, maybe thats getting the pump running when not needed?
Runs a bit once the engine has started.