I recently had to chase down a vacuum leak to solve a P0171 issue. My choices were: a) Take it to a dealer or mechanic who would charge a "diagnostic fee" to retrieve the same code I already had ($50), charge for a smoke test to find the leak ($100), and then an hour's labor ($100) plus parts to fix it. Just guessing the $ amounts. b) buy a smoke machine and try to fix it myself.

I decided to take a chance on a cheap Chinese smoke machine from Amazon. $80 for a Solary SD301. It worked great. I found the air leak in minutes. Smoke was pouring out from beneath the lower plenum. Engine is a 3.4 V6. I took apart the induction system and injected smoke into various hoses. The lower O-ring on one fuel injector was leaking. I had just installed a new set of injectors from MotorWest Performance. Either the O-ring was bad or more likely I did not install the injector correctly. Fortunately MotorWest included a few extra O-rings. I replaced the O-ring, reassembled, and smoke tested again. No leaks. P0171 is gone and 4Runner runs perfectly.

For anyone who repairs cars I think one of these machines is as essential as a socket wrench set or a code reader. Until very recently smoke machines were out of reach for the amateur mechanic. Snap-On $2340. Even Harbor Freight $499. Snap On will probably still sell theirs to shops but Harbor Freight will never sell theirs because they compete for the same amateur mechanics who buy as cheap as possible, probably for one-time use.

Interesting video of the smoke machine being manufactured. These Chinese workers are dexterous and fast.

Solary SD301 Smoke leak assemable - YouTube

Anything can be a smoke machine if you use it wrong enough...

Luckily, I have a couple friends with shops and smoke machines. They are 100% necessary if you work on turbo cars... But for $80, I would seriously consider having one at home.

-Charlie

I went with an autoline pro, made in the USA iirc. Works well and can use baby oil as a fuel

Thank you, this was very timely. My other vehicle has an exhaust leak I just cannot find. Smells like exhaust (not gas) whenever the gas engine kicks on but the vehicle is not moving. This will work perfectly.

Moving to General Discussions so others can benefit.

You can use a paint can to make a ‘smoke machine’.

Done it a couple times.


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