There are so many requests for solving problems that usually start with "do a smoke test for vacuum leaks" that there's a real need to have a single thread dedicated to smoke testing. Then we can just post the link to this thread when someone needs smoke testing info. Please chime in with your tips, links, experience, etc., and I'll curate it all in this first post. I'd like to dedicate this thread to @jfoj for posting most of this information in various threads over the years. I plagiarized his posts heavily. 🙇
Smoke Testers
Common Leaks
Smoke Test Videos
BAVauto Diagnostic Smoker - P0171 and P0174 Smoke Test
How to Find Vacuum Leaks With a Cigar (Life Hack)
How to Make a Smoke Machine
BEST automotive smoke machine you can build
Smoke Testers
- Amazon.com: automotive smoke machine
- smoke test machine for sale | eBay
- Amazon.com: smoke test machine automotive
- https://forum.e46fanatics.com/showpost.php?p=18615591&postcount=144
- Smoke machine, finally
- Stinger Evap Smoke Machines OFFICIAL SITE - Affordable Professional Smoke Testing Machines For Car Smoke Tests - EvaporativeSmokeMachines.Com
- https://www.ecstuning.com/b-bav-aut...diagnostic-smoke-machine-smoker/b8800109~bav/
- start with a fully cold engine, some leaks go away with heat expansion of parts
- put the front end up on jack stands so you can get under it while looking for smoke
- remove all engine covers (top and bottom), air box, and anything else blocking good visibility all around the intake manifold (power steering reservoir, cabin microfilter tray, etc.)
- use a mechanics mirror and bright light to search for smoke
- open the oil filler cap while you pump lots of thick smoke into the intake until smoke is coming out the hole then replace it, that ensures smoke has filled the crankcase, keep pumping while you search for smoke leaks
- remove the one-way valve from the brake booster grommet, plug it well, then see if the STFTs go down
Common Leaks
- Upper and lower intake boots
- Upper intake boot around F connector
- DISA main O-ring and shaft area
- Vacuum hoses and plugs at the rear of the intake
- Fuel pressure vent hose that connects to the F connector on the upper intake boot and under the drivers floor board where it connects to the fuel pressure regulator
- CCV and hoses, especially the lower oil return line
- Dipstick and dipstick guide tube
- Oil fill cap
- Valve cover gaskets and cracked valve covers
- SAP vacuum line to Kombi valve on front of engine, this will not leak smoke because of the control valve under the rear of the intake
- Power brake booster, sucking jet pump, and related hoses
Smoke Test Videos
BAVauto Diagnostic Smoker - P0171 and P0174 Smoke Test
How to Find Vacuum Leaks With a Cigar (Life Hack)
How to Make a Smoke Machine
BEST automotive smoke machine you can build