Car Start but Engine Initially Backfire

The car starts but initially backfires after starting. When a car backfires shortly after starting and usually occurs on the wet condition, then this is a sign of the problem of moisture inside the distributor cap. Moisture is the results of condensation from the air humidity, and interferes with the ignition system thereby causing the engine backfires shortly after starting.

However, if the car problem occurs even when the condition is not wet then this could be a problem of fuel injection system or one of the electronic sensors is faulty.

Possible cause of engine backfire at initial start

(1) Moisture on distributor cap or faulty sensors

(2) Problem with the fuel injection system

Moisture in the distributor cap

As indicated, if backfiring only occurs in wet conditions. This is a telltale sign of moisture on the inside of the distributor cap. The moisture is condensation which results from the humidity in the air. This seriously interferes with the ignition system's ability to operate properly, causing this vehicle to backfire.

How to fix engine backfire at starting involving moisture in the distributor cap

For moisture on the distributor cap, there is nothing much to do. Just avoid parking your car on open space especially if you anticipate rain. It isn't much you can do in this situation except, in the future, park this vehicle in a dry place (i.e. a garage) when you anticipate rain. This should help.

Problem with the fuel injection system
It could be that the fuel injection system or one of its many
electronic sensors is faulty. This could possibly cause backfiring. If this engine is also backfiring while driving.

How to fix engine backfire at starting involving a problem with the fuel injection system.

As for the faulty fuel injection system, bring the car to a reputable car shop and ask the mechanic to check the fuel injection.

Fuel injection systems are complex and hard to diagnose. If the car is not under warranty, take it to a mechanic that has expertise in this particular make/model. We highly recommend you get a second opinion if the first mechanic suggests that you need a new fuel injection system. Very often, the problem is not the fuel injection system itself but rather one of its sensors. A skilled mechanic will be able to determine if all the sensors are working properly.

Again, if the mechanic told you to replace fuel injection, do not agree unless you seek a second opinion.