CHECK ENGINE LIGHT CAME ON

[99bimmer]

engine light came on on my 93 325is took to get fault code read said it was 02 sensor ok so i got a new one put in...they also said there was a stored fault code for my knock sensors (what does that do???) but was told it shouldnt be a problem well check engine light isnt on till i was driving to work the next day and it came back on then later that night on the way home it went off.should i look into y my check engine light did that or was it a glitch...also what should my rmps be at idle cause there just alittle over 500 is that normal or should it be higher....any suggestions on whats going on thanks....Ben

[Bengali86]

Ok, this is strange,

My name is Ben, i have a 93 325is too... I had my engine light come on, it was my O2 sensor too. i had it replaced, a couple of days later,my car was still acting strange (engine light was on again) RPMs would bounce up and down, i took it back in, they said they gave me a faulty O2 Sensor, so they replaced it again, also my #2 Knock sensor was down, so i had both replaced (sensor #1 and #2) what they do is when they sense Knocking/pinging they adjust the valves (?) correct me if i am wrong.. thats the self adjusting valves, the '93 M50 engines have a different fuel injection system and knock sensor system than the '94+ models

healthy RPMs for you car is betwen 500-700 rpms at idle

cool car and cool name Ben



~Ben

[99bimmer]

hey thanks for the response and thats wierd we have same name and car.....so about how much money would both knock sensors be if they do become a problem cause everything seems fine on the car i guess since the check engine light went off and the rmps are right....plus how do u like the ac stuff on ur car hp gains and prices...Ben