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Guest Message by DevFuse
 

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CEL on, Knock sensor code, no symptoms


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14 replies to this topic

#1 crazyhorse001

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Posted 02 March 2007 - 07:45 PM

My CEL came on this afternoon, so I swung by the "Zone" & had it checked. It showed a knock sensor code. They cleared it & all was good for 10 mins, then it came back on. I checked the sensor & module plugs, & both are tight. There are absolutely no drivability issues, which I'd expect from this. No loss of power, no miss, no difference in MPG. What the heck! Am I getting a "phantom" CEL?, or could a tiny amount of piston slap fool the knock sensor? I get a light knock at startup, but it only does it for 15-20sec.

#2 nipper

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Posted 02 March 2007 - 08:04 PM

When you get a knock sensor code, its the knock sensor. The knock sesnor is a piezo electric quartz sensor that produces an AC signal (think microphone).
Just cause you have no drivability issues, means that you have a well running car.

Get a new sensor and make the car happy.


nipper

#3 crazyhorse001

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Posted 02 March 2007 - 08:09 PM

Ok how much is this gonna take outta my temporarily unemployed budget? I LOVE Subies, but damn if they're not mind readers... well ok paycheck readers! LOL

Oh yeah BTW.... Thanks Nipper

#4 nipper

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Posted 02 March 2007 - 08:32 PM

If you have no driveability issues, and no need to get an emissions inspection any time soon, you can let it go for a while.


nipper

#5 chef_tim

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Posted 02 March 2007 - 08:53 PM

I got one when I put my moter in, IIRC about $90 from the dealer. Tim

#6 nipper

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Posted 02 March 2007 - 08:57 PM

LOVE Subies, but damn if they're not mind readers... well ok paycheck readers! LOL

Oh yeah BTW.... Thanks Nipper


I know. Blu not only wants a seondary o2 sensor, but also wants a drive shaft boot and a wheel Bearing.
All this cause Blu knew i was getting my SSI back award. Now i have to explain to Blu that the insurance company gets that check, not me. And i can't do any of the repairs myself :(

nipper

#7 crazyhorse001

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Posted 02 March 2007 - 09:04 PM

Blu's gonna be MIFFED! I'd be suprised if she doesn't find some more for ya just for that! LOL

#8 Gloyale

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Posted 03 March 2007 - 02:03 PM

I ran my 86 GL Turbo for years with no Knock sensor at all, simply because I could not find one(for less than $200). Didn't ever seem to be an issue. No CEL, back then the Knock unit was seperate from ECU. I think a piece of black tape will fix the CEL until you can afford a new (or used) knock sensor.

#9 nipper

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Posted 03 March 2007 - 02:14 PM

The only problem with the black tape is if something else goes wrong and he gets an angry CEL light. i dont condone putting tape over them anymore for that reason.
Now if he wants to see if he can get a used one in junk yard or two, that may work well.

nipper

#10 Gloyale

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Posted 03 March 2007 - 02:40 PM

The only problem with the black tape is if something else goes wrong and he gets an angry CEL light. i dont condone putting tape over them anymore for that reason.
Now if he wants to see if he can get a used one in junk yard or two, that may work well.

nipper


If he can't fix it now, then the light will be on anyway, and he won't know if a new prob comes up cause the light is already on. The tape is a VERY temporary solution. He should fix it soon or at least put a resitor on there to fool the ecu and turn off CEL.

#11 crazyhorse001

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Posted 03 March 2007 - 04:55 PM

so, worst case, I'll get another CEL that i dunno about, one that could cause damage. I intend to fix this asap, but it's gonna be a couple weeks. A Knock sensor is $71 online... as was mentioned it's $90@ the dealer. I don't do JY electronics, you're still getting 10yr old parts. Assuming nothing else breaks in the interim, I'm not gonna do any damage right?

#12 nipper

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Posted 03 March 2007 - 09:32 PM

If you had no issues till now, i dont think you will hurt anything. If you notice a decrease in performance or any other oddities, then you'll need to replace it sooner then later.

nipper

#13 Gene J

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Posted 03 March 2007 - 09:41 PM

With a bad knock sensor the computer gets very conservative on ignition timing, so no engine damage occurs.

Mileage will be poor and power will be down. If you do not check mileage or romp through the gears you will not notice any issues.

My wife didn't notice but I did!

#14 crazyhorse001

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Posted 11 March 2007 - 09:38 PM

UPDATE:
The CEL comes & goes now, once it's on, it stays on till a restart. I can confirm it only comes on @WOT. I'm not sure about what codes it's throwing... is there a "cheater's way" to pull them with OBDII?

#15 nipper

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Posted 11 March 2007 - 11:18 PM

UPDATE:
The CEL comes & goes now, once it's on, it stays on till a restart. I can confirm it only comes on @WOT. I'm not sure about what codes it's throwing... is there a "cheater's way" to pull them with OBDII?


Yes just go to an autoparts store and have them pull them.

nipper




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