416tt

iTrader: (1)

Hi guys,

I noticed my engine light and vsc lights came on two days ago and then after a restart went away.

It's been two days and today the lights came on again and I noticed a hesitation in acceleration.. got the codes scanned I believe they were p0330 and p0325 for bank 1 sensor 1 knock sensor. They wiped the code so I'm going to drive it to see if it comes back on but has anyone else had this issue? Where is this sensor located?

Thank you

Bgw70

I am posting the check out procedure for you...the knock sensor is located on the engine block.

Did you recently fill the car with gas that was lower then 91octane? Or you may have received some bad gasoline.

Helogadget

My bet would be bad gas (or the ECM). I think it would be highly unlikely to have both sensors fail simultaneously. Could happen though I guess.

Bgw70

Agreed Helo, the bad gas should be it. The problem sounds like it is new and not reoccurring.

I think I jumped the gun going straight to the service manual checkout procedure! ;-)

416tt

iTrader: (1)

Hi Guys,

thank you for your replies .. really appreciate it!! and thanks for diagnostic steps bgw!!

I always use 91... considering moving up to 93 as its only 3 cents more..

Sorry just a correction Im not actually getting both codes .. just the P0325 (Bank1 sensor 1).. I have had it reset twice and it seems to come back the next day or so.

Now the bad part is that the top part of engine has to come off to reach these sensors apparently? and both are located in same spot.. if my sensor is bad should I replace both because of the bad location or would you guys think just the harness is bad?

Thanks again

Bgw70

Just guessing, I would think the sensor is bad unless you think the harness moved and became really hot.

416tt

iTrader: (1)

got this pic from painguy's post from this link

https://www.clublexus.com/forums/gs-...roblems-5.html

Going to have to get in there to see anything .. UGHHHHHHHHHHHHHHHHHHHH

Helogadget

Looks like these sensors run around 150.00 each. Tough call, should you replace both? I personally have not heard of these commonly going bad so I might be inclined just to replace the bad one. Of course I have never pulled the intake before and if it is labor intensive (looks like it might be) that might make me lean the other way.

416tt

iTrader: (1)

Hey Guys,

so the light came on about 3 times after resetting it and usually took about a day to come back on which made me feel that the bank1sensor1 may actually be bad. specially because that gas already ran out and I filled from different gas stations in between. So I went ahead and placed order for 2 brand new oem sensor...

after that I reset the light, and decided to put supreme 93 octane.. drove the car around for a while and the light never came on... filled 91 and took it for a short trip and it still hasn't come on.. been about 3 days (still using the 91 as usual).. looks like you guys are right about the bad gas..

So the sensors might have been ordered for nothing ... ill keep them for a bit and if not needed they will be in the classifieds. keeping fingers crossed!

anyhow ill keep post back if anything.. thank you

Bgw70

That is Great news bimmer!
The big question, why did this code start showing up?

Did your regular gas station change fuel distributors, bad gas or did you use someone else?

Did something change on your car due to age, mileage, old spark plugs, dirty fuel injectors and/or dirty throttle body?

When I purchase my SC, I ran Chevron Techron fuel system cleaner in the tank and I sprayed out the throttle body with CRC throttle body cleaner. How about new spark plugs...
These are inexpensive alternatives and may help!
http://www.ebay.com/itm/Chevron-65740-Techron-Concentrate-Plus-Fuel-System-Cleaner-20-oz-/111628166822?hash=item19fd8ea6a6
http://www.ebay.com/itm/CRC-Throttle-Body-Air-Intake-Cleaner-5-oz-05678-Auto-Car-Truck-/151661433666?hash=item234fb9d342

kjcole

As we all know, 'knock' is from pre-detonation of fuel, which can happen when octane is too low (fuel explodes from heat of compression, rather than from spark). Modern cars can adjust their timing on-the-fly in response to predetonation as sensed by these knock sensors. So, today when you hear pinging, you really have a problem because even maximum timing adjustments aren't working, and that extra heat can start melting stuff. Sometimes in high mileage cars there can be carbon deposits that build up on the top of the piston that retain heat too long, thus predetonating the fuel mixture. Happens less these days because of specific additives that most refiners/blenders use. Maybe that's what happened here ('bad' gas is usually less volatile, not more), and the carbon deposits loosened up, or the knock sensor is flakey, etc. In the old days we'd take take those big-block V8's out on high-acceleration runs to 'blow out the carbon' - quite literally.

Harold57

I used to have to do that on an old Corolla I had also. I get it up to 60 and stomp on it and you could see the puffs of smoke come out and it immediately became more responsive. (It only had a 1.2 liter engine, so that was pushing its limits...)

Something to look out for and may have happened here is when gas stations refill their tanks it causes whatever debris is on the bottom of the station's tanks to stir up and can get into your tank as a result if you just happen to filling up then. Whenever I see a tanker truck at a gas station that I was heading to, I just move on to another or wait another day to fill up, when possible.

BTW, I'm glad that you got it resolved without replacing parts!

416tt

iTrader: (1)

Hi

Thanks guys,

Bgw - nothing on my car changed and im not sure about the gas stations having a change distributors..

Kjcole - thanks for the detailed response, always good to learn more .. Hmm I have had low fuel certain times

Harold - thanks, but guess what it came back on.. I have been trying different gas stations and problems seems to be coming back again..

it lasted that time 4 days without coming on and now it keeps coming after a day or so.. now im just wondering wether its just sensor or something is actually up.. however I do have the sensors now so I guess I might aswell replace :/ hoping that shud solve it.

Bgw70

Bimmer, did you run a tank of chevron Techron?
Did you spray out the throttle body?
How many miles are on your car?
How about new spark plugs?
Do you have any bad coil packs or plug wires?

I am just trying to save you from changing the knock sensors because what happens if they do not fix the issue. This is a really big job...
This really started happening all at once.

Harold57

BTW, we can also cause garbage pickup when we run our tanks really low, especially on the older cars (like my 2002). Sediment will accumulate over time and when running the tank close to the bottom, it can be picked up by the fuel system.