What causes a vehicle to backfire?
This car that backfires is not my car. There is a car in my neighborhood that backfires like 4 times in 20 feet.
- ruskinflgatorLv 51 decade agoFavorite Answer
There are several reasons, the most common these days is excessive fuel in the exhaust hitting a hot catalytic converter and lighting off. the others are A ignition backfire caused by the spark occurring when the exhaust valve is open, and from a flat cam lobe.
The former is rare, and was a major problem in the 80's n GM vehicles. the ignition misfires are caused by a bad distributor cap or the wrong firing order on the plug wiresSource(s): ASE Mastertech
- LynetteLv 44 years ago
About 20 different things.Did not give enough info.Backfiring through intake(popback) or exhaust???Some things that will cause backfiring is unburned fuel(HC)in the exhaust system from your vehicle running too rich.If you have a smog pump on your vehicle a bad diverter valve will cause a backfire.Backfiring can also just be from a bad exhaust leak such as at the exhaust manifold gasket.It is actually pretty easy to listen for exhaust leaks.All you need is a stethoscope.Take the rod off of the end of the stethoscope and listen for a hissing sound around exhaust joints.Remember backfiring through the intake is a symptom of a lean condition,while backfiring through the exhaust is a symptom of a rich condition.
- How do you think about the answers? You can sign in to vote the answer.
- Michael BLv 61 decade ago
Worn valves or bad valve timing. If the inlet valve and the exhaust valve both partially open at the same time, unburnt fuel escapes into the exhaust manifold. This ignites, causing a backfire. I have had a backfire that completely split open a new silencer (muffler).
- 1 decade ago
A possible intake manifold or exhaust manifold leak could cause a backfire.
- Richard GLv 51 decade ago
Vehicle needs a tune-up!
- Anonymous1 decade ago
A buildup of unburned fuel in the cylinder, usually caused by bad timing adjustment.
- (A)Lv 71 decade ago
A momentary lose of ignition during the running of a engine.Source(s): DE
- 1 decade ago
when combustion occurs with the intake vlve open