Cheap engine vacuum leak tester

[KCsTJ]

Saw this on u tube and copied.

Had a vacuum leak on my 97 2.5L. I could hear but not locate. So I made this cheap smoker using a $6+change hand liquid transfer pump from HF. (I used my 20% off coupon).

I attached the red hose from the hand pump to the vacuum hose from the brake booster. I used a round rubber thing I found in the shop and it fit perfectly to plug up the throttle body.

I had to buy a pack of 5 cigars cuz they were the right size cigar to fit the hand pump. $7+change.

Here's the set up with the cigar attached. Lit the ceegar and pumped the hand pump. Within a minute I found the vacuum leak, a plastic tube from the gas tank to the purge canister cracked. Repaired the plastic line and she runs like new.


So for under $15 it's diagnosed and fixed, a nifty cheap vacuum line test.

 

[KCsTJ]

By the way, this set up is even easier to use on the 4.0.

I tested my 4.0 today also and will post a pic tomorrow.

 

[KCsTJ]

Here is the same setup on my 4.0L. I just removed the brake booster hose from the intake and connected the the red hose from the hand pump.

Don't forget to plug the throttle body. I used a.plummers rubber end cap that happened to fit exactly.

Remember if you find a leak u must perform this test again until no smoke is seen.
When the leak(s) are found you're done. I opened the throttle body butterfly and pumped the cigar smoke out.

Very easy and takes all the guess work and dread out of troubleshooting vacuum leaks.

 

[zebra12]

Very nice, I have a vacuum leak in my Grand Caravan that I cannot locate. I'm going to give this a try.

 

[Jeepn_Texas]

Very nice, I have a vacuum leak in my Grand Caravan that I cannot locate. I'm going to give this a try.

Hey Guys?
You are working WAY too hard on this!
Get out your propane torch,
Start up the jeep, let it warm up.
Then tun on the torch BUT DON'T LIGHT IT!
Point the gas coming out of it towards where you think the vacuum leak is.
When you gas the area where the leak is the engine RPM will change!
You will be going from lean to rich and you will notice it!

Once you narrow down the area, check all seals, gaskets and hoses for issues, cracks, etc..
You can use a fire flick to narrow it down.

 

[Nimbley]

For evap leaks a smoker is very helpful. For everything else a water bottle with a small hole poked in the cap is all you need. Start the engine and hit the suspect areas with water. When you hit he leak you’ll hear the engine miss. Propane or sprays that burn aren’t that accurate. The leak will eventually suck in the fumes as they build up leading to inaccurate tests.

 

[Jeepn_Texas]

For evap leaks a smoker is very helpful. For everything else a water bottle with a small hole poked in the cap is all you need. Start the engine and hit the suspect areas with water. When you hit he leak you’ll hear the engine miss. Propane or sprays that burn aren’t that accurate. The leak will eventually suck in the fumes as they build up leading to inaccurate tests.

I have found the turbulent air under the hood of a running jeep and small amount of propane involved does not accumulate. Never had much success with water, though did try when away from home, as you have to hit the leak directly. Some folks are not comfortable with the propane method, I have been using it for 40 years, never had an issue greater than having to grow back eyebrows... just kidding.

Same technique used in industrial Vacuum metallurgy equipment, but in that case they use Helium and a sensor sensitive to it inside the machine. Helium is one of the smallest molecules in gaseous form, can get in to damn near anything.