how to check for vacuum leak?

[ronn227]

What hoses do I check for a possible vacuum leak? does anyone have a diagram?

Ron
1994 530i

[winfred]

i use a can of carb cleaner if the idle changes you've found the spot, in v8 bimmers the problem spots are the seals at the front and back of the intake manifold, the 8 intake to head seals and the pcv plate on the back of the intake has a diaphram that fails, when we get a bad running v8 car in and a leak is found we pull the intake and do everything as it can all fail and cause problems

[jj7]

i use a can of carb cleaner if the idle changes you've found the spot, in v8 bimmers the problem spots are the seals at the front and back of the intake manifold, the 8 intake to head seals and the pcv plate on the back of the intake has a diaphram that fails, when we get a bad running v8 car in and a leak is found we pull the intake and do everything as it can all fail and cause problems

I once tried the propane torch,but sometimes i feel that the engine fan makes it bit hard to make sure,since it blows it away...but as for the carb cleaner,would it make the idle faster or slower?since i got this running problem and the idle would drop alone,besides,i feel some cylinders are not firing correctly on slight pedal.

TIA

jj

[ryan roopnarine]

2nd the carb cleaner since its so cheap. i was looking like a madman for a vacuum leak on my car. hosed down the tbody gasket, the intake manfold mating area, the injector holes, brake booster connections, et cetera. almost gave up. on a lark, i put the straw on the can and fired it like a fireman to the icv nipple. the car surged forward, almost running over my foot in neutral, then almost died. on my car, it seem s to drop the idle, was always under the impression that it raised it.....ymmv.

[Javier]

ICV compensation for the increased RPM. When the rich juice is gone, ICV is almost closed, too much for the gas mixture.

Javier

[InfernoM3]

What hoses do I check for a possible vacuum leak? does anyone have a diagram?

Ron
1994 530i

I also would like to see a diagram. My car has been acting funny. I already replaced 02 sensor and ppl saying might be a vacuum leak. (different post).
I am not quite sure which are vacuum hoses? I diagram would help.

[winfred]

the m30 only has two small vacuum lines, they go into the bottom of the intake plenum, one goes to the fuel pressure regulator and the other goes to the breather tube that ataches to the valve cover, beyond that the air boot that goes from the air flow meter to the throttle body and breather tube are the only other places to have a leak

I also would like to see a diagram. My car has been acting funny. I already replaced 02 sensor and ppl saying might be a vacuum leak. (different post).
I am not quite sure which are vacuum hoses? I diagram would help.

[winfred]

the m20 only has one that goes to the fuel pressure regulator

I also would like to see a diagram. My car has been acting funny. I already replaced 02 sensor and ppl saying might be a vacuum leak. (different post).
I am not quite sure which are vacuum hoses? I diagram would help.

[danzee]

I found holes in two well hidden vacuum hoses on my E34 M50TU. They were very deteriorated at about 160,000 mi.
The hoses are located in the area just behind the top of the oil filter top cover, and connect under the plastic manifold cover. Two different diameters. I posted the P/Ns about a year ago ago.

[InfernoM3]

the m30 only has two small vacuum lines, they go into the bottom of the intake plenum, one goes to the fuel pressure regulator and the other goes to the breather tube that ataches to the valve cover, beyond that the air boot that goes from the air flow meter to the throttle body and breather tube are the only other places to have a leak

Can anyone point out which hose it is in a diagram in www.realoem.com
I've been searching through this and my bentley and can't find it.