Pulled This Code

[john_18]

So i went and pulled the code on my BMW this morning. Turns out its knock sensor # 2. I guess that would explain the "shimmy" i get every now and then when im crusin down the road. Heres some info about it.

"The knock sensor is used to detect pre-ignition that can damage the engine. If the knock sensor is triggered, it will back off the timing of the car, reducing the 'pinging.' A fault is generated if there is an open circuit, a ground fault, or if the sensor sends multiple signals that don't correspond to proper engine operation."

my question now becomes how in the world do i fix it? And am causing more damage to the engine by driving it? I need HELP!!!!!!!!!!!!!!!!

[frank3]

First thing I'd do is to see if your gas is causing knock sensor to go on alot...bottom line, if you're using regular gas, you'll trigger the knock sensor and cause it to go crazy. Depending on your model, you'll need either 89 or 91 octane for your car.

If you have old plugs and/or a lot of carbon buildup on the pistons, this will cause greater heat inside the cylinder and cause premature ignition...

If one of the above is your problem...then the fix is easy. If not, other posters will be able to provide suggestions.

[john_18]

what exactly is premature ignition? The car has been sittin still for quite sometime before i got it so i was going to do a tune up i.e. plugs. IM sure i could do a search for what plugs are best for my 318 is but i dont have time now. If its not a bother could someone please tell me which are best for my 318. Thanks.

[john_18]

one more question- What if I ran about 5 gallons of CAM 2 gasoline through the motor? WOuld that help clean out the injectors and such?

[BlantonG13]

The best plugs to get are the stock ones that they came with. MGK or Bosch make them. I couldn't find part numbers, but any local auto place will have them. Don't get any "super or platinum" because a BMW ignition system is made to perform optimally with the stock plugs because it uses lower voltage.

Make sure you use 90 or 91 octane gas most of the time, regular gas every now and then won't hurt it though. Throw in a bottle of injector cleaner and run it out and that should do a significant job to clean your injectors.

[walshja]

this may sound weird, but I have a 1994 325iC, and when I first got the car I ran it with 91 octane gas. Well the car pinged a lot, so I thought I would try 89 octane, and she runs perfectly now.

I know that makes no sense, since 91 should ping less than 89, but does anyone have any idea why that would happen?

thanks, joe

[97alpineM3]

This is probably due to the octane and how combustable it actually is.. this would require a little research to answer...

Les