Easy way to find vacuum leaks - perfect for troubleshooting ACCII or vacuum locks.

[thorsen]

After chasing down vacuum leaks in my ACCII system the last time I had an issue, I grew very frustrated with unplugging lines from connectors and pulling a vacuum with the mity-vac only to discover there were no leaks. The problem being that the connector could have been the leak in the first place and the act of removing and reinserting the line and connector could have resolved the leak.

I did some research and decided a smoke tester was what I needed. The smoke machine fills the vacuum lines with smoke under a slight pressure and any leaks are highlighted by escaping smoke. It's a great idea but the machines are very expensive - even used they are in the $500 range. That was out of my price range.

I looked on eBay and found a smoke/fog machine for $20. This is a 1500cfm (seems optimistic to me) 400 watt unit that uses a water-based solution to create fog. It comes with a wired remote control and a manual button on top.

[thorsen]

I hooked a hose directly up to the exhaust of the machine and soon discovered that there was not enough pressure behind it to push it through 10' of tubing and into a vacuum line on the car. Now I start to see why the real machines cost $100's of dollars.

Undeterred, I start digging around. I find a 12 volt cage fan from Radio Shack. I blocked the exhaust of the fan off with a piece of plastic and threaded a hose adapter into it. I hot-glued a 1.5" PVC connector onto the intake side.

[thorsen]

I hooked the fan up to a 12 volt lead-acid battery and butted the intake of the fan up to the exhaust of the smoke machine. I bumped it and a lot of smoke "escaped" but the fan pushed a fair amount through 10' of hose.

[thorsen]

I pulled the vacuum line off the manifold for my cruise control and Unwired Tools ACCII upgrade. This line is on the front of the manifold, crosses the engine bay at the firewall, and then comes up about 1/2 way on the passenger fender. I poked a hole in the vacuum tube that goes to the cruise control after the check valve.

I pulsed the smoke machine on/off a few times and the hole was obvious. It's hard to tell from a static picture but the smoke was moving and was very easy to see.

[alabbasi]

I thought about doing the same. Great idea.

[Gurunutkins]

a brilliant bit of engineering on the fog machine there

I am going to give that a try - always wanted a smoke detector too

glad you found the hole
cheers
Barri

[thorsen]

This actually works very well. I used it last night to trouble-shoot the locking circuit. It blew smoke from the firewall all the way to the vacuum reservoir in the trunk, then blew smoke out the grommet where the vacuum line goes in the reservoir. I removed the reservoir, tapped the hole for a threaded barbed fitting, and reinstalled it.

[MattBelliveau]

This is a great thread. Could one get the same benefits from blowing cigarette smoke through the lines (Yes, I smoke)?

[thorsen]

I don't know. Can you blow enough smoke to fill 10' of vacuum tubing with enough pressure to force it out of any leaks? That would be tough I think.

[Jim300D]

thorsen, this is an ingenious idea and a great thread. Thanks for sharing I can't wait to diagnose all my vacuum problems and start modifying a smoke machine such as yours! Looks like it makes diagnosing far easier and quick. Kudos!