Smoke testing an engine for boost leaks

Smoke testing an engine for boost leaks



Original Poster:

742 posts

9 months

Friday 11th June
quotequote all

I have a maserati biturbo, that doesn't seem as urgent as it used to, the boost needle use to just tough the red under hard acceleration, now it just gets into the orange. (green / orange / red)

the solenoid was 20 years old so i changed that early in the year and for a while the urgency came back, but has gone again.

Starting with the cheaper easier tests first.

is it simply a case of using a smoke machine and pumping smoke into the intake and let the engine produce the pressure / vacuum or do i need to pressurise the intake system ?



34 posts

80 months

Saturday 12th June
quotequote all
This might not be the answer to the question you're asking, but the smoke machine such as this contains both a smoke generator and an air pump.

Therefore, within reason, ie the sheer volume of the system being diagnosed, it is capable of pressurising the intake system. Not by much - only a few psi, but enough for the smoke to leak and be seen.

So, for example, last year I had a leak on the breather system of my Esprit, so I simply connected the smoke machine to a bung which fitted in place of the fuel filler cap, and the machine pumped in the air/smoke mixture until the pressure of the whole system was raised enough for smoke escape at the leaking hose, and be seen to be doing so.

There is no need to run the engine whilst doing an intake pressurisation test, indeed I'm unsure how the engine would behave in response to being fed with an intake mixture including burnt baby oil.

In my experience, it is better to do the test in subdued light and then use a torch to highlight the leak(s).

I am aware of simpler/cheaper smoke machines than the one I have linked to above, and of course there are DIY ones. In both cases I believe that you can use a separate compressor to generator the intake pressure, and the smoke generator to just generate the smoke.

Edited by ColourRestorer on Saturday 12th June 07:32