How can i detect vacuum leak?

Question

I know the error code 171 means i have a vacuum leak in my car, BUT how can i detect this leak? what should be tested to find out where the leak is? thank you in advance

Answer 1

year make and model of vehicle would help in providing you with better help, as some engines are prone to patterned problems...however the safest way to find a leak would be to use water and not ether or any other flammable. Also reving the engine to 4k rpm's

is strongly discouraged. not to mention more difficult to distinguish where the vacuum leak is at with all that noise created by the engine.. just pour some water starting at the lowest point (the intake manifold) and try crimping rubber hoses as you go along..caution not the hard plastic lines .those are fuel lines and they will break. tip..listen for slurping noise and/or

watch the engine react. it will start to stumble once you hit the leak with the water ..after all cant burn water.

ps egr not fully seated will also cause a lean mixture

try tapping on egr to see if a change occurs.  

Answer 2

have some one in the driver seat hold the gas peddle at about 4,000 rpm and you go under the hood and spray some either wd40 or something from an arosol can and spray around the carb and intake and heads and all that stuff and youll find it when the engine revs up or chokes out then youve found it

Answer 3

You can hold a long piece of vacuum tube to your ear and hold the other end to the vacuum lines, injectors, intake manifold and anywhere else you suspect the leak. Do this with the engine at idle. Anything you hold it up to will be amplified. you can use this "tool" to find bad injectors, loose valves, and bad bearing in belt drive accessories. You can use a long piece of copper tube hooked to the vacuum line to get at hard to reach areas. Spraying fluids on a hot, running engine may start a fire. Its really entertaining when your know it all boss catches a customers car on fire this way.  

Answer 4

best is a vacume leak tester