Check Engine

[Raynald]

Hi,
i have a BMW 1994 318i, since on week i have the check engine ligth on occationaly...(on off)
What is the basic to check first...
THank You

[jenmcd]

This might sound silly but my check engine light went on because the gas cap was loose. If you plan on doing any do it your self work, buy a reset tool with code reader and a Bentley manual. Saves lots of $$$ in no time.

Keith

[Wayne 962]

The code reader is the best value - we sell it for $139. It will tell you all that the computer finds wrong with the fuel injection...

-Wayne

[canyonlands]

It sounds like the O2 sensor. Is it the original? Did it first happen within 10 miles of a putting gas in the tank?

[Raynald]

i thing to know what is happining,
in my area Shell (the gas station ) have contaminated fuel,
and now it is OK
Thank You for your help...
Raynald

[canyonlands]

Bad gas can often wreck an O2 sensor. Don't be surprised if it comes back. O2 sensors are fairly easy to change at least.

Good luck,

Ron

[Wayne 962]

Out here in CA, the gas is so bad that the car will knock sometimes, even on high octane. The knock sensor in my 325is keeps going off...

-Wayne