LPG Backfire protection?

[Jxfwsf]

lol this guy, Old post !

I did the same thing on my VP except I fiber glassed the inside of the box for extra strength to ! Worked really well.

Best to source the problem and fix it instead of bandaids, if the system is an impco type backfires can detroy the diaphragm in the mixer.

 

[DavoVP]

Best to source the problem and fix it instead of bandaids, if the system is an impco type backfires can detroy the diaphragm in the mixer.

I agree, And I did but every so often it would let go, Its just the nature of a mixer style system on a V6.

 

[Tasmaniak]

Mine has a hole drilled into the air intake pipe and then what "looks like" a beer cooler slid over the hole with two large hose clamps. The idea being, should it backfire, it will hopefully expand the beer cooler and then go back down. Never back fire so couldn't tell you. Mine understanding is that it's not that uncommon.

 

[lowandslow]

Not enough ignition advance will cause your intake backfire.
Put foot down, engine sucks in more gas than gets burnt in the following cycle, your intake tract is now full of unburnt LPG which is waiting to detonate.

 

[Jxfwsf]

Mine has a hole drilled into the air intake pipe and then what "looks like" a beer cooler slid over the hole with two large hose clamps. The idea being, should it backfire, it will hopefully expand the beer cooler and then go back down. Never back fire so couldn't tell you. Mine understanding is that it's not that uncommon.

Very common mod but it shouldn't be clamped, the idea is the vac from the intake keeps the stubbie holder covering the holes (it should be a tight fit so not really needed) and a backfire then has an escape route, maybe some decent rubber bands but nothing to solid.

Not enough ignition advance will cause your intake backfire.
Put foot down, engine sucks in more gas than gets burnt in the following cycle, your intake tract is now full of unburnt LPG which is waiting to detonate.

Most commonly if it's not something in the ignition it's a poorly tuned setup, sudden acceleration it leans out and bang.

 

[jeepster]

even if you can stop the airbox blowing itself apart, the backfires are going to damage amongst other things the airflow meter(read expensive).

Something is amiss in your system to be causing the frequent backfires . If the person that installed it cant find it, tell them you are going to take it to someone else to see what is wrong and you will be forwarding them the bill, this should get it fixed one way or the other.

It takes a really big explosion to kill the MAF sensor of an Ecotec. What usually happens is that the honeycomb mesh (for laminar flow) is blown out, and won't fit back in. So people leave it out. Then the engine runs wrong on petrol - too lean or too rich, I forget which.

 

[ultimate_gas]

Good system tuned properly shouldnt backfire.
Plugs should be reduced from 1.5mm gap to 1.3mm (NGK BPR6EFS-13) best plug to use.
Good leads.
Coil packs also very common and if not changed this could be your issue. Because the Commodore employs waste spark system the residual LPG in the manifold or cylinder not on it's compression stroke about to be fired can be ignited by this waste spark. Coils are very cheap these days worth changing, very simple DIY job also.
Vacuum leaks are another cause particularly after one backfire, this commonly blows off the fuel vapour purge hose from under the throttle body which will lead to a vacuum leak and susequently more backfires. Leaking injector seals are also a cause though less common, poor ignition is no.1 cause on Commodore V6 and once rectified you should not need backfire protection.
You can get one way flaps that fit inline with air intake duct, this is mainly to protect airflow meter and will stop damage to airbox.