Q: Backfires on start up

asked by on December 04, 2016

Runs rough backfires through carborater on cranking

My car has an automatic transmission.

Backfiring can be caused by a number of faults. If the ignition timing is incorrect either by the distributor being out of alignment or a jumped timing chain, backfires can occur. Also, if ignition wires are crossed / incorrect firing order, backfires can occur. Also, too much or too little fuel due to faulty fuel injectors or incorrect fuel mixture can cause a backfiring condition as can faulty spark plugs. Other mechanical issues such as burned exhaust valves in one or more cylinders can cause backfiring.

Since any of multiple components can be the cause, have a certified technician look into the backfiring to isolate the exact cause.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Turn signals don't work right when I have headlights on but when there off everything works right

If the turn signals and headlights are both activated by the same column-mounted "combination switch" a possibility is there an internal fault with that switch. If the two circuits are not working off the same "combination switch", there is some...

Secondary air pump.

The air pump supplies the catalytic converter with extra oxygen so that it can efficiently catalyze any unburned fuel. On start up, the catalytic converter is cold and requires some help to quickly get up to temperature allowing it to...

Battery dead after a few days

Thanks for writing in about your Mercedes Benz CLK430. This is a common problem as vehicles get older. This type of fault is called a parasitic draw and occurs when one or more component does not shut off when the...

Related articles

A Buyer’s Guide to the 2012 Mercedes-Benz R-Class BlueTEC
The The R-Class isn’t a minivan. It’s not a station wagon either – though it bears the slight air of one. Mercedes deems it a crossover, and that may be the closest appropriate designation but it’s not an exact match...
Top Automotive News & Stories: September 24-September 30
Angry Civic Type R, 350 special edition Ferraris, Infiniti variable compression tech, Mercedes' electric future, and more.
5 Comfortable Sports Cars Your Parents Won't Complain About Riding In
The most comfortable sports cars combine high performance with a smooth ride. Options include the Alpina B6, Audi S8 Plus, and Mercedes-AMG S65.