Skip the auto shop - Our mechanics make house calls

Q: How can I tell if the fuel injector is bad or if it is just the o-rings that need to be replaced, without taking them out to check?

asked by on

Had issues all of a sudden with the car, seemed to happen right after fueling. A few miles later pulling into the driveway the car started sputtering like losing power and then died. The abs and traction control light came on. Tried to restart it and it had a VERY strong fuel smell and white smoke and was hard to start. After smelling the gas we stopped trying that day. Put the scanner on it and ended up replacing a sensor and took care of one problem and the other code said #5 was misfiring. We decided to replace the spark plugs and wires and the mechanic said that there was a lot of carbon and fuel on #5. How can we tell if it is just the orings or if it is the injector itself that needs replaced? Still have fuel smell and white smoke. There is no coolant leaking in, the oil looks fine.

My car has 130000 miles.
My car has an automatic transmission.

A: Hi and thanks for writing in. When it comes...

Hi and thanks for writing in. When it comes to determining what part to get, first you need to know what each part does. The O-ring on a fuel injector serves two purposes. The o-ring seals the injector from leaking any fuel out of the engine when the engine is running. Also, the o-ring creates a seal to keep air flow strong so there are no vacuum leaks on the runners of the engine’s intake. When there is a lot of carbon on a cylinder, that carbon is unburnt fuel and can cause a lot of problems. Carbon is sticky and cause the rings to not expand making a cylinder have internal blow by. Plus, carbon holds heat, so when fuel is entered, then the fuel can ignite before the spark plug is energized. This is called pre-detonation. White smoke from the tail pipe is an indication of too much fuel in the exhaust system. I recommend getting an engine cleaner for the fuel system and vacuum system. Some suggestions are fuel injection cleaner or sea foam. Sea foam is very powerful and you would need to check the label before using it. Then after cleaning the engine out, drive the vehicle around to see if the problem continues. I also recommend replacing the injector for it probably is leaking fuel and not spraying it. If you would like help, consider having an expert automotive technician from YourMechanic come to your home or office to inspect and diagnose this issue for you, and make or suggest any repairs as needed.

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: Need help with a reduced engine power warning light.

Hello - first thing to check is what problem code remains set. If still a TPS, double-checking the wiring at the throttle body, and also checking the throttle pedal actuator sensor. This is the "transmitter" whereas the throttle position sensor...

Q: SUV parked for three years

Hi. Parking a vehicle for that long is never good. Things like wiring, starter, fuel pump, and transmission can all go bad from lack of use. In severe cases, engines do seize up from rusting internally due to lack of...

Q: Instrument cluster shuts off intermittently while driving

There are two fuse boxes on the vehicle. One is inside of the firewall usually located in or around the dashboard. Have you checked this fuse box and the fuse box in the engine compartment? The dash cluster itself may...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...
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.