mr_g

i was wondering how would i do a vaccum leak test on my 85 nissan sentra??..

 

bob89sentra

You could take a can of starter fluid and spray it around the vacuume hoses and intake manifold. If there is a leak your idle speed will fluctuate. If you have a vacuume gauge hook it to manifold vacuume and see where it is. It should be holding steady around 12-14in, depending on what elevation you live at.
There is a great vacuume system diagnosing section in the chiltons repair manual, if you don't have one you should get one
Bob

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89 Sentra owner 9 years 205,000 miles and counting!

mr_g

my car has a carburetor....so i spray it in the carburetor??..how would i measure it with the gauge and where can i get it where do i put it in the carburetor??..i do have a chilton's repair manual....sometimes my car fluctuates sometimes it doesnt....i dont wanna go through checking all the hoses cause thats alot of hoses to go through....my bro in law has a boost leak tester that he made but its for turbo cars only plus my car is a carburetor so that wouldnt work....he would just plug a hose onto his turbo intake side and shoot air into it and just listen to where the air is leaking....so i was thinking if he shoots it in the intake can i just shoot air into my carburetor??..i dont know if that'll work or not just guessing here :S....

2ndb18

put a vaccum gauge on the brake booster vaccum hose.

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84 B11
91 Ifiniti G20
03 Pathfinder 4x4 se
Nissan Technician- Nissan of Fife,Washington

bob89sentra

No No No...
You spray the strater fluid on the vacuume hoses and around the intake manifold while the engine is running. Usually a vacuume hose will crack on the end where it hooks up and is easy to identify. If there is a cracked vacuume hose it will suck the starter fluid in through the vacuume leak and change the speed of idle. You want to hook the vacuume gauge to the intake manifold vacuume, the brake booster line is a good place. I wouldn't put pressure in any of the vacuume system and hoses to check for leaks.

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89 Sentra owner 9 years 205,000 miles and counting!

 

mr_g

ok im not much of a mechanic so im asking my bro in law to help me....since u say hooking up the gauge to the brake booster line is a good way would i have to cut that hose and put the gauge into that hose??..then buy a new one and replace it??..well thats what my bro in law said that i had to cut it to be able to put the gauge in it then just buy a new one and replace it later on or is there another way without cutting it??..

technik

you can get some soupy water and put it on there and turn the car on and watch for bubbles

mr_g

also once i put the gauge on would it tell me exactly where the leak is or like where its close too??..or does it just tell u if ur having a leak or not....sorry im a newbie when it comes to car :S....

2ndb18

just pull the booster line off of the brake booster and put the guage on that. It will tell you if you have a vaccum leak or not. It will not tell you where it is.

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84 B11
91 Ifiniti G20
03 Pathfinder 4x4 se
Nissan Technician- Nissan of Fife,Washington

mr_g

j/c if i buy a vaccum gauge can i also use it for a compression test??..or do i have to buy a gauge specifically for the compression test??..is there a vaccum and compression gauge that comes in one that i can buy??..or r they both 2 different things....

 

bob89sentra

A compression tester would be seperate from a vacuume gauge. There is a clamp that holds the vacuume hose to the brake booster. Just loosen the clamp and pull the hose off the booster and hook the vacuume gauge to it. The vacuume gauge can tell you if you have a leak, or if the timing is off, plugged exhaust, burnt valves, ect. It will not tell you where it is.

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89 Sentra owner 9 years 205,000 miles and counting!

mr_g

i looked in my chiltons book and found a vacuum sensor in my car....i was wondering if hooking up the gauge to that would also work for testing vacuum leaks??..