Corolla 2005 misfire problem

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Corolla 2005 misfire problem

I have 2005 Corolla. I am facing misfire problem with the car on CNG. I have noticed that it misfire when the engine is hot i.e. Starting the car again after running 15-18 kilometers, I have changed the plugs a week ago but the problem still exists. The strange thing is that there is no problem with the performance. In past when the car misfire it blows up the air filter box and it also affect the performance. When I changed the plugs my car�s mechanic put a couple of screws in air filter box and now it do not blow up the air filter box on misfire. I hope putting the screw will not cause any internal damage.

Please suggest what is causing misfire, where it can get this fixed (permanently) and any ideas how much the fix will cost?

Thanks

Gari.pk User 10093 asked on 13 Oct 2010 14:23:27 pm

1 Answer

220 views |

Daani - on 13 Oct 2010 14:23:54 pm

Sir

misfiring is related to tappets, your valves are opening and not closing properly , i.e they are loose

we all know the concept of the 4-stroke internal combustion engine

1.suck
2.squeeze
3.bang
4.blow

know we will look at when valves are open for the intake cycle i.e taking in the air fuel mixture , if the tappet adjustment is not spot on , the valve opens late and can be delayed till the bang (when the spark plug fires)

now imagine your engine going at 4,000 rpm it happens pretty fast

so lets have an equation

Open Valve+faulty tappet clearance +short circuited coil pack+an intake manifold full of highly combustible gas e.g
CNG and we as a result have=a blown intake manifold+an expensive and tedious fix

so prevention is the best cure

thank you