Alan in Alabama
New member
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.
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.
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