Skip the auto shop - Our mechanics make house calls

Q: I have a problem of petrol going through to the oil sump and the car backfire and some smoke coming out of exhaust.

asked by on

When I start the car it idles ok when cold and when getting warm it start to idles rough and smoke coming from exhaust,when I rev the car it backfires from exhaust,and I can smell petrol from the exhaust.After switching it of and checking the oil,the oil is full of petrol and oil is very light because of petrol mixing with it.i have changed injectors thinking that it inject too much petrol but nothing has changed.
My car has an automatic transmission.

A: Hello. If your oil is being mixed with fuel...

Hello. If your oil is being mixed with fuel then you are either getting too much fuel into the engine or you have a serious internal engine issue. Most of the time this is caused by worn out piston rings. If the rings are worn out then the fuel will bypass the rings and enter the oiling system. I usually do a compression test to verify if this is possible. If the compression is fine then I suspect that the computer is commanding too much fuel into the engine which is usually caused by a failure in the computer or an issue with one of the sensors. I use a scan tool to check the sensors first and then test the computer from there if needs be. If you want to have this fuel in the oil checked, consider getting some help from YourMechanic, as a certified mechanic can come to your home or office to [diagnose why there is too much fuel entering the engine] https://www.yourmechanic.com/services/smoke-from-engine-or-exhaust-inspection

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
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

Q: Every time I drive the epc light goes on and it's says check engine service now and sometimes it just cuts off while driving

Hello. If your warning lights are on then the first thing I would do is retrieve the trouble codes, as they will likely reveal some insight on what the issue may be. Warning lights and stalling can be caused by...

Q: Changing gears issue in VW Jetta with manual transmission

The odds are that it isn’t. Volkswagens have a very funky shifter setup and the linkage is kind of a mouse trap setup. Inside them, there are various plastic bushings, and your car is an 'O1, so it is 15...

Q: My 2010 Mercury Mariner makes a rattling sound when accelerating

The noise you are hearing is most commonly known as pinging or pre-ignition. This can be causes by the mass air flow sensor running the engine lean or if you do not have a flex fuel vehicle then running a...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.