FAQ Smoke Machine

How do you find leaks with a smoke machine?
The LeakMaster™ generates a thick, long lasting Diagnostic Smoke® vapor from a non-toxic compound. When this smoke is introduced into the system to be tested, it quickly exits wherever there’s a leak – See the smoke and you’ve found the leak.  Additionally, the patented UltraTraceUV® solution when vaporized deposits a fluorescent dye at the exact location of a leak.  All you do is use a conventional ultraviolet (UV) light – much like you would an A/C system. This dye is especially helpful finding those hard to see leak locations.  Or introduce the vapor into an engine before tear-down.  The dye will reveal internal leaks otherwise not easily seen.

In the automotive industry some common leaks that can be found are; EVAP, OBD-II mass airflow, vacuum / induction, exhaust, EGR, oil seals, idle motors, brake boosters, under-dash, vacuum-heater controls, intercoolers, turbochargers, wind / water, axles and many more.  Other industries such as Aerospace, marine and industrial have similar leak applications as well as industry-specific leaks.

What is Diagnostic Smoke® and UltraTraceUV®?
Diagnostic Smoke® is a special vapor-producing solution that quickly identifies a leak’s location when introduced into a system to be leak-tested, by simply looking for the exiting vapor. UltraTraceUV® is a Diagnostic Smoke® vapor-producing solution that contains a special ultraviolet-activated fluorescent dye that gets deposited at the exact location of a leak.
I’ve heard some people say that the “OEM-Approved” oils are the same as generic mineral oil, such as “baby oil”, is that true?
No that is not true. Doing a very simple comparative analysis of two oils to merely determine what the basic sources of the oils are can be very misleading.  Most non-synthetic oils are of a “petroleum” base and many can be categorized as being a “mineral oil”, but the end product can be significantly different.  Upon closer analysis the truth is revealed.  The OEM-Approved oils that have been approved by all automakers using smoke technology is not “baby oil”.  In fact, baby oil is not intended for industrial use.  The OEM-Approved UltraTraceUV® formula is a highly refined mineral oil-based solution; blended in a special formula to be able to withstand the high temperatures during the oil’s vaporization process; is patented and approved by all* automakers using smoke technology. (*The only other OEM approved solution is STAR’s optional non-dye solution used by Toyota).
Why is it necessary to use an OEM EVAP-approved smoke machine in the vehicle’s EVAP system?  
Our licensed STAR Diagnostic Smoke® vapor machine technology didn’t just pop-up over night.  It took literally years of development, in collaboration with OEM-partners; Ford, GM & Chrysler to develop the ‘right’ technology in order to get the ‘right’ kind of smoke vapor.  These thousands of man-hours of research and testing allowed us to develop the right technology for their EVAP systems. What we ended up with is technology specifically built to major automakers’ specifications. Our OEM EVAP-approved machines will not damage vehicle components (including the activated charcoal, all sensors [including O2], catalytic converters, gaskets, seals, etc) and will not void the vehicle’s factory warranty.
What are some of the unique characteristics of your OEM approved technology?
Through extensive research, in collaboration with the big-3 U.S. automakers, it has been determined that during vapor (smoke) production proper temperatures must be achieved and maintained in order to develop the ‘right’ smoke for a vehicle’s EVAP system testing. The right temperatures are critical for several things to happen, three of which are:

  • Producing the right consistency of dryness in the smoke.  Not using heat in the process produces nothing more than a cold atomized wet fog – highly undesirable for the activated charcoal and other components of the vehicle’s EVAP system.
  • Creating the best environment for the UV-activated dye molecules, in the UltraTraceUV® solution, to properly ‘bond’ with the smoke solution’s molecules.
  • Then when pressure-differential and temperature-differential is created (like at a leak-point) the smoke particles exit the leak while the UV dye is deposited at the location of the leak.

Maintaining the right temperature is achieved with sophisticated microprocessor controls.

When operating the EVAP-approved smoke machine, is it necessary to constantly control the pressure, or perform any other cumbersome tasks?
NO!  The big-3 OEM’s requirement was very clear and specific; do not make the machine’s pressure adjustable! The OEM required a fully automatic machine that made it impossible for the technician in the field to make an honest mistake, by applying too much pressure into the volatile EVAP system. Besides, using higher pressure does not find more leaks – except maybe for the ones you’ve created. See question # 9 below.
In what other systems can The Smoke Machine be used to detect leaks in?
The smoke Machine can be used to detect leaks in any system where air travels such as: Vacuum Systems, Throttle Bodies & Carburetors, Injector Seals, EGR Systems, Brake Boosters, Under Dash Vacuum & Ducting, Intercoolers & Turbochargers, Exhaust Systems, Idle Motors & Solenoids, Pre-Assembly Component Leak-Testing (such as Cooling Systems, Engine Gaskets, Diaphragms, Many Oil Seals & Gaskets), Pneumatic Door Lock Systems, use our special adapter to find Wind & Water Leaks (around Doors, Windows & Sunroofs) & Many Others!
Should I use a non-combustible gas, such as nitrogen, instead of compressed air to test the EVAP system?
Yes!  See SAE International Technical Papers on potential testing hazards: http://www.sae.org/technical/papers/2007-01-1235 and http://www.sae.org/technical/papers/2008-01-0554 It is a fact, and studies support, that it only takes 11% of oxygen in a fuel vapor system to support combustion!  Using ambient air, which contains 21% oxygen, is extremely risky since that is more than twice the needed oxygen content.  Studies show that the safest method of pressurizing the fuel vapor system of a vehicle is with a non-combustible gas such as nitrogen instead of an oxygen-rich compressed air. That is why virtually all auto manufacturers that use smoke technology recommend / require the use of nitrogen when testing the vehicle’s EVAP system. Adopt safer working habits and procedures, especially when you are testing a volatile system like an EVAP system. There are at least two risk factors associated with using compressed air, when testing the EVAP system, and you should do everything possible to minimize the risks.

  1. The oxygen introduced into the fuel tank will inevitably exit along with the flammable gasoline fumes, either through a leak source in the EVAP system or through the EVAP system’s canister vent valve.  Ignition can take place at those and other locations if static electricity or some other external ignition source is present, such as when the canister vent valve is back-probed closed on vehicles lacking bidirectional communication. We all know there are many other potential sources for ignition in an auto shop environment and many of us have heard or read about gasoline fumes catching on fire, creating a very hazardous situation. Using nitrogen reduces the oxygen content of the mixture in the leaking fumes and reduces the chances of the dispersing vapor from ever reaching the Lower Explosive Limit (LEL) of gasoline.
  2. Testing the EVAP system of a vehicle using compressed air usually means that you will be adding the equivalent volume contained in several gallons of vapor space.  Under many conditions, there will be enough oxygen added to the fuel vapor space that will warrant a safety concern.  Filling the fuel vapor space inside the tank with more than 11% of oxygen creates a fuel-to-air mixture that will support combustion. In fact, University studies have shown that it takes only one to five minutes of air introduction from any smoke machine to render much of the fuel tank’s vapor space flammable. There are also documented cases where the fuel pumps inside fuel tanks have developed overheated wiring harnesses hot enough to ignite a flammable mixture.  So now any vapor leak leaving the fuel tank can become a sort of “fuse” back into a volatile fuel tank mixture. (Download evidence of internal ignition sources [pdf 363 kb] — [pdf 162 kb] )

Using an inert gas, such as nitrogen, is the most sensible, simplest and least expensive insurance you can have to reduce the risks mentioned above.

What other benefits does nitrogen have?
Some of our smoke machines designed for industrial applications require them to produce very high pressures (some as high as 120 PSI).  An inert gas, such as nitrogen, must be used with those high pressure machines because the oxygen in shop air will cause a ‘flash’ effect inside the smoke machine chamber. All smoke machines manufactured today, when used with shop air, will flash if enough pressure is created inside the smoke chamber (flash can start to occur between 15-30 PSI).  Our licensed nitrogen patents allow us to manufacture smoke machines for these high pressure applications.

Chrysler, in their older vehicle models, used air with a Leak Detection Pump (LDP) to perform their onboard EVAP pressure tests, why shouldn’t I use air with a smoke machine?
Any vehicle with an LDP was designed to introduce very little air into the fuel tank, in order to maintain its ‘too rich to burn’ fuel-to-air mixture (approx. 1.5 liters of air volume). A smoke machine can easily introduce 50 liters of air volume into the fuel tank, creating a flammable condition inside the fuel tank. This MOTOR article explains: [pdf 277 kb].
Can I use a [cold] fog-producing machine for leak detection purposes?
Any machine that produces a cold fog may be suitable for theatrical stage antics but is not suitable for professional leak detection purposes.  Any machine that does not use a heating element is considered a cold fog machine.  A cold fog machine simply atomizes a liquid solution.  (Just about any solution can be atomized, even water).  What you get is a heavy wet fog that can be very unfriendly in today’s sophisticated automobiles – most especially in a vehicle’s fuel vapor recovery (EVAP) system.  EVAP systems are equipped with an activated charcoal that must maintain its integrity, otherwise you’ve just made matters worse.  In other words, the wet fog can saturate the activated charcoal, rendering the EVAP system ineffective and most likely voiding the vehicle’s warranty. Another disadvantage is that the wet fog has a tendency of quickly condensing inside the system being tested, lacking that “hang time” required to properly travel through an entire test system.

The only way to produce the right kind of smoke – the smoke approved by the big-3 U.S. automakers – is to use a source of heat in the process. At the right temperatures (not too hot or not too cold) a very special thing is created we call; Diagnostic Smoke® vapor.  Only then can you achieve the correct consistency of a small vapor particle size and a ‘dry’ smoke – that best happens with sophisticated microprocessor temperature controls like our EVAP-approved machines have.  Also, and just as important, you must use the correct solution such as the patented UltraTraceUV®; the only solution approved by the big-3 U.S. (and other) automakers and deemed to be safe to use in their vehicle’s EVAP systems.

OBD-II vehicles already confirm if a leak in the EVAP system is present. So why then do I need the ‘phase-one’ feature on your EVAP machine?
Our EVAP machine’s ‘phase-one’ feature, which verifies if an EVAP leak is present, is important for two simple reasons; (1) Sometimes a vehicle may come into your facility with more than one code. The phase-one feature is an excellent way to verify if an EVAP leak indeed is present and (2) It is good practice to quality control an EVAP repair and to verify if the vehicle has additional leaks after the EVAP repair. It is not practical to release the vehicle not knowing for sure if an EVAP code will turn on again.
Do you offer a discount for schools?
Yes, we offer an extremely attractive school prhttps://web.archive.org/web/20190619120431/mailto:info@TheSmokeMachine.comogram.  Contact us at 1.888.459.9955 or email us for details.
What basic warranty is provided?
All of our smoke machines and their accessories are warranted against any and all defects in material and workmanship for one (1) year from date of purchase.
I notice you offer few machines with a pressure-decay feature. What value does pressure-decay offer in an EVAP system?
Actually, very little. Without a computer to calculate the complex mathematical calculations, it is impossible to compare a pressure decay-rate to a known leak size. Pressure-decay is only going to tell you if there is or isn’t a leak, not if it is a 0.040” or a 0.020” leak.  And in many cases, it can’t even do that.  Due to the increase of fuel tank pressure, caused by fuel evaporation in the fuel tank, it is more likely that a pressure-decay gauge will ‘think’ there is no decay (leak) because the rate of fuel evaporation is greater than the leak rate of a very small leak (e.g. 0.010″).  The reverse effects are just as troubling, since fuel tanks can also create a vacuum in the tank.  Either way, they can lead to a misdiagnosis.  It could also cause you to be wasting your time looking for an “acceptable” EVAP leak that didn’t cause that MIL lamp problem you are trying to fix. That is why the Big-3 U.S. auto makers had us develop a flow meter that can be calibrated with our machine’s internal calibration orifice in order to achieve this exact leak rate calculation.
Where can I purchase your smoke machines?
Most likely through the tool dealers you already purchase tools from since they most likely sell SPX/OTC tools – so ask them first. Otherwise, for an automotive application in the USA and Canada contact SPX/OTC.  If you have industrial, marine or aerospace applications, contact us at email