Quote:
Originally Posted by stlrj
" Small amount from injector seals 4 and 6."
When engine is running, it's under negative pressure and injector seals were designed for negative, not positive pressure.Smoke machines produce positive pressure so leakage is normal.
Cheers,
Joe
87 Carrera
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Joe,
A good o-ring will prevent the unmetered air from going inside the motor. A smoke machine needs only a very low pressure (1~2 psi.) to detect an air leak. If air or smoke gets through the opening, cracks, space, etc. it will show during the test.
I totally disagree with your assessment that the air leak around the injector o-rings is NORMAL. This is false and misleading. You will never have a good running CIS if you allow these leaks to persist. There should be no smoke coming out of the air box, intake runners including rubber boots, injector o-rings, pop-off valve, vacuum lines, etc. during a smoke test. The POV works better under vacuum. This is how you test the integrity of your vacuum system.
What the smoke test does is locate the hard to find leak source/s. If the smoke could escape from the system under test, imagine what will happen to the ambient air if sucked by the vacuum producing motor.
Summary:
A smoke generator is very effective in locating those hard to find air leak sources in a CIS motor particularly underneath the airbox. This is more efficient than the pressure air and soapy water method. Fix all sources of air leaks and your CIS will be running reliably for a long time. It is the lack of understanding about CIS that makes people hate this system in some way.
Tony