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04 Outback H6
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230 Posts
You don't need to remove the intake manifold. (I think only the H6 requires you to take of the intake manifold)

You just need a socket, ratchet, and a long enough extension.
 

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1997,legacy wagon 2.5
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30 Posts
Thank you. I will try that. Guess I will figure it out.
It makes me upset when I can't do things I could before. I have the same problems when I work on my 1980 TR8. Just hard to move old joints.
Thanks again,
Ponybow
 

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1997,legacy wagon 2.5
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30 Posts
Now I see how you do it and all I can say is thank you, thank you. I just got the Subaru and have so far replaced both front cv joints, had the cases and transmision all pumped out and refilled. The PO had done nothing. Now I get the knock sensor light. I really like this little wagon.
Thanks again,
Ponybow
 

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'00OBW, '96&'94 Legacy - all rusted RIP, current: 2016 Focus MT
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4,804 Posts
You should also notice a nice little bump in power and fuel economy once you get the P0325 cleared up.
 

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1998 subaru outback 2.5, 2 tone green on grey
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69 Posts
Hi Ponybow

You would need a socket rench and an extender to reach the knock sensor. You also need to almost be on top of the engine near the firewall. It's a tight squeeze but you can do it.
 

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2001 Outback Limited, 2.5L
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34 Posts
Is there a real need for a torque wrench? or can I use a normal wrench and gently tighten it a bit??

Thanks
 

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'00OBW, '96&'94 Legacy - all rusted RIP, current: 2016 Focus MT
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4,804 Posts
Probably don't absolutely need a torque wrench, but too tight it can crack it again and too loose maybe it would see knock that isn't there or throw the code again.
 

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2001 Outback Limited, 2.5L
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34 Posts
Tried cleaning the knock sensor and where it bolts, check engine light went off for a while but came back. I ordered a new sensor last night, when it arrives I'll install the new one and see what happens.


Thanks
 

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1997,legacy wagon 2.5
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30 Posts
This is a great site. It is you all that guided me on that did the nice work.
Again thank you.

:7: ponybow
 

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2001 Outback Limited, 2.5L
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34 Posts
Bought a new sensor from eBay, same brand as the one Subaru uses. Paid 52 bucks for it shipping included, yesteday I installed the new one drove aroud for a while no Check Engine light so far. I also noticed smoother acceleration, better response so I'm assuming the mileage is going to improve.

I didn't use a torque wrench I did a mark on the block so I positioned the new sensor at 60 degree angle.
 

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1997 Legacy Outback Limited, new 2.5L
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33 Posts
Just to list the symptoms of my bad knock sensor:

Irregular acceleration
Slight but noticeable hiccups when holding constant speed
Sluggish when cold and at low RPM's
Won't shift to 1st gear on a rolling stop
Doesn't like to downshift
Poor mileage -- 14-17 mpg

Once I fixed it, every symptom went away. VERY easy fix.

Hope this helps
 

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2007 Outback Wagon
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191 Posts
Hey guys - two really quick questions about knock sensors, as this is quickly looking like it might be the part truly been behind my CEL woes for two years.

1) I've seen them for as low as $30 shipped on eBay. Is that something I should be weary of?

2) I've seen it written in some places that an audible "knocking" is something that may be indicative of a bad KS. For a long time, when I've started up my car, I've heard kind of a rapid knocking sound that persists for a brief period, but generally goes away shortly after I start driving. Not very descriptive, I know, but is there any chance that this might be that knocking that they're referring to?

Thanks so much!
 

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1999 30th Anniversary Legacy Outback DOHC 2.5L 4EAT, 2008 Impreza WRX 2.5L 5MT, 2008 Impreza Wagon 2.5L 4EAT
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1,224 Posts
Hey guys - two really quick questions about knock sensors, as this is quickly looking like it might be the part truly been behind my CEL woes for two years.

1) I've seen them for as low as $30 shipped on eBay. Is that something I should be weary of?

2) I've seen it written in some places that an audible "knocking" is something that may be indicative of a bad KS. For a long time, when I've started up my car, I've heard kind of a rapid knocking sound that persists for a brief period, but generally goes away shortly after I start driving. Not very descriptive, I know, but is there any chance that this might be that knocking that they're referring to?

Thanks so much!
1) I bought a Bosch one online from a reputable parts shop (not Subaru) and when I installed it the CEL went away (Code was P0325)

2) I agree with kmltick that it may be piston slap. It could also be rod knock but I don't really know.

The function of the knock sensor is to work with the ECU to permit advanced ignition timing to improve fuel economy and reduce emissions. The ECU advances the ignition timing and when it detects Knocking (via the Knock Sensor) it retards the timing advance to prevent engine damage.
 

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2007 Outback Wagon
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191 Posts
Followup question: is piston slap something serious, and would require immediate attention? For what it's worth, it's not a terribly loud sound...I usually can't even hear it if I'm trying to listen for it outside the car; I only notice in when I'm inside.
 

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2007 Outback Wagon
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191 Posts
Sorry, another question: how important is having a torque wrench when installing a knock sensor? Can I just tighten it with a regular ratchet wrench until it's pretty tight, but I'm not cranking on it with all my might? I don't own a torque wrench, and I'd rather not have to buy one. Thanks!
 
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