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Guest Message by DevFuse
 

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Just ordered knock sensor part for 98 Legacy Limited, couple questions


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15 replies to this topic

#1 arod812

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Posted 19 August 2013 - 06:44 PM

I just ordered it off eBay for $8 dlvd.  What is the difference between this new part and the new one for $83 at auto zone?  Also should this help solve some of the issue where the car should perform like usual instead of hesistation feeling?  

 

Any Subaru guys from the Grand Rapids, MI area on here at all?



#2 Fairtax4me

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Posted 19 August 2013 - 08:19 PM

Quite a few from MI, and several in GR.

Difference in the $8 part and the $83 part, probably no difference except wholesale and retail markups. Lots of people have had good luck with the EBay knock sensors, I wouldn't question the quality a bit. They're very simple sensors, no moving parts, and don't need to be expensive.

#3 johnceggleston

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Posted 19 August 2013 - 08:35 PM

What is the difference between this new part and the new one for $83 at auto zone?

 

$75.00


Edited by johnceggleston, 19 August 2013 - 08:36 PM.


#4 cohophysh

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Posted 19 August 2013 - 11:41 PM

I bought a cheap ebay knock sensor...no problems so far!



#5 grossgary

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Posted 20 August 2013 - 05:23 AM

a failing knock sensor will retard the timing and hesitate, bad gas mileage, etc.  whether yours is failing or not we can't say, you didn't even mention if the check engine light is on and if the knock sensor code was recorded.  if it is, then it should help.   if not then you likely need NGK spark plug and OEM or at least high quality spark plugs wires, and maybe spark plug gaskets if they're leaking (plugs will have oil on them).

 

$75.00

 

 

lol!

 

i've used a ton of ebay sensors, thing is they are so easy to replace (one bolt) and so cheap who cares if you had to replace it one more time...though i've never seen that happen.  if you're worried, keep the old one in the spare wheel well.  with a DOHC EJ25 that knock sensor is way down the list of probable issues you'll have in the future.



#6 arod812

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Posted 20 August 2013 - 11:55 AM

I believe the car has the 2.2 in it,  although I can't tell from the marks and distinctions people told me to look for.  The metal plate with the VIN and Engine type said some letters then 22 and continued with letters so thats where I'm getting its a 2.2 from.  The check engine light was on and I posted the codes in my previous thread I had made.  



#7 Fairtax4me

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Posted 20 August 2013 - 01:27 PM

Just to the left of the plug on the alternator, look straight down at the top of the block. The engine code is cast into the block.

Attached Files



#8 arod812

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Posted 21 August 2013 - 09:29 PM

Do any of you members know anyone in the Western MI area?



#9 Blue Whale

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Posted 22 August 2013 - 02:44 PM

It's crossed my mind that the very cheap sensor might just contain a resistor and not be able to sense anything.  That would mean no more codes, and no more retarded timing, but also no timing correction to avoid pinging.  I'm especially concerned about this possiblilty, as I replaced the sensor on my 2000 OB a few weeks ago and I have heard some pinging under load on certain occasions since.  That's never been the case before with this car, nor with any other Subaru I've driven (since 1993).  For this reason, if the knock sensor on a my wife's turbo engine were to go bad I'd hesitate to use a cheap no-name replacement.  My engine won't self-destruct from occasional pinging, but hers might.



#10 arod812

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Posted 27 August 2013 - 05:49 PM

Replaced the part yesterday and it runs like it should.  Still looking for someone to possibly help out with my other code that I'm getting in my area or a great referral



#11 Fairtax4me

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Posted 27 August 2013 - 07:56 PM

It's crossed my mind that the very cheap sensor might just contain a resistor and not be able to sense anything. That would mean no more codes, and no more retarded timing, but also no timing correction to avoid pinging. I'm especially concerned about this possiblilty, as I replaced the sensor on my 2000 OB a few weeks ago and I have heard some pinging under load on certain occasions since. That's never been the case before with this car, nor with any other Subaru I've driven (since 1993). For this reason, if the knock sensor on a my wife's turbo engine were to go bad I'd hesitate to use a cheap no-name replacement. My engine won't self-destruct from occasional pinging, but hers might.


If you suspect that, measure the resistance of the cheap sensor against a known good original sensor.
IIRC it should be around 580 K ohm.

#12 johnceggleston

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Posted 28 August 2013 - 06:39 AM

the proof is in the pudding.

 

if it is just a resistor, it will turn off the CEL,

it is not going to improve how the car drives.

 

iif it drives better, then it is working.



#13 steveb3

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Posted 09 September 2013 - 12:51 PM

I am experiencing a rattle/ping sound after warm up under aceleration over 20 mph and am wondering if it could be knock sensor related. CEL has not come on and mileage and performance are great. But the sound is similar to other postings when it's sensor related and occurs at the same time as others have explained. I did just get a new short block and cat installed and had the injectors cleaned. 06 Legacy 152k on it  And thoughts? Thanks, Steve



#14 Fairtax4me

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Posted 10 September 2013 - 12:02 PM

Possible the old knock sensor has gotten "slow". It's also very easy to over tighten the sensor and crush the piezo element that creates the signal. This could make the sensor numb and not respond to a knock unless it is severe.

Very easy to inspect and replace. Search for a thread called "Knock sensor 101" that covers removal, inspection, and replacement.

#15 arod812

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Posted 10 September 2013 - 09:43 PM

Well my knock sensor made the check engine light go off then a few days later it seemed to come back on and it doesn't have as much power as it did but more than it did when I replaced it.



#16 Blue Whale

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Posted 11 September 2013 - 12:56 AM

I didn't measure the resistance of the cheap replacement sensor, but I have no doubt it's in the correct range.  I only wonder whether a knock will be detected.  Performance isn't any better with this one, but it was just fine before.  There was just a CEL that would return every few hundred miles.






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