Smoke test question

[Hoffbrohaus]

Rigged up my own smoke tester and it works great, found leaks in throttle body and those rocker caps under the valve cover. Fixed all those and now...

When you run a smoke test and everything is sealed up properly where should the smoke/air go? Logically I would think through the exhaust valves and out the tailpipe. However, now when I run the smoke test there are no leaks and it builds up enough pressure that the cap I put in the intake boot (tightly) always blows out. Does that mean I have blockage somewhere?

and just so you know:
5psi of compressed air via smoke machine
Through intake manifold on FPR vacuum line
AFM removed and boot sealed
Throttle open

[ahlem]

It will get to 5 psi unless you have a place for the pressure to go, like if the intake and exhaust valves are open at the same time. I made my own smoke tester to chase a code on my X5 and 15 minutes later I opened the oil filler cap and relieved the pressure.
Sort of depends on where you apply the pressure. You don't always pressurize the intake.
You can pressurize through your EGR system or your brake booster to check for other leaks.

[jlevie]

The ideal place to inject smoke is with a plug containing a nipple that replaces the AFM, secured with a band clamp. The exhaust must be plugged so that smoke can't leak past an open valve. If your DIY smoke machine is working properly it should never exceed 4-5psi. You can verify that with another pressure gauge. Note that to find all possible leaks the system must be pressurized with smoke for 10-15 minutes.