knock sensor?

Heads, valves, pistons, rods, crankshaft, etc...

Moderators: Helpinators, Moderators

Post Reply
josh_90_leg
In Neutral
Posts: 34
Joined: Fri Dec 04, 2009 9:55 pm
Location: spanaway, WA

knock sensor?

Post by josh_90_leg »

So my knock sensor is going out and of course the check engine light is goin on and off when it wants to, i was wondering if it should be fine to drive another few hundred miles till i can fix it....it shouldnt be messing anything else up or have any other problems should it? its coming on more frequently now too....
mike-tracy
Moderator
Moderator
Posts: 5000
Joined: Tue Aug 25, 2009 7:52 am
Location: Des Moines, Wa

Post by mike-tracy »

You'll be running rich with a faulty knock sensor signal, but shouldn't be a big problem.
1992 Legacy SS 5mt, build in progress
Josh Colombo wrote: Mon Jan 14, 2002 10:23 am Wait....I'm confused now.
ciper
Knowledgeable
Knowledgeable
Posts: 4388
Joined: Tue Oct 15, 2002 8:16 pm
Location: SFCA

Post by ciper »

And you will be running with absolutely crap timing so the car will feel slow. It would probably run fine on 80 octane fuel like this lol
tahiti350
Third Gear
Posts: 874
Joined: Fri Feb 03, 2006 7:17 pm
Location: Spanaway/Tacoma, WA

Post by tahiti350 »

I drove from Oregon to Texas with a bad knock sensor... car would rattle on hard pull, onramps, etc... BUT got an average of 32 MPG for the trip.... I also had one injestor that started dying at idle going thru Salt Lake City, ran fine off Idle, so I kept going.

It definately WASN'T pulling timing...
'90 Bermuda Blue L Wagon (Wife's),
Auto, AWD, Now with 275K + miles!



2005 Outback, 2.5 AWD (wife's new daily)
BSOD2600
Fourth Gear
Posts: 1636
Joined: Tue Sep 12, 2006 6:49 am
Location: Seattle, WA

Post by BSOD2600 »

I can say with 100% certainty (via lots of data logging), that when there is lots of knocking, the ECU WILL reduce the "octane factor" parameter and the "knock retardation" parameter will increase. Once octane factor falls below 25%, extra fuel is added (WOT is about 1 AFR more rich) . Timing map is also reduced when its not at 100% either.

'11 WRX Limited
'94 SS | 3" TBE, 07 TMIC, TD05H-16G, Revtronix Stage 2, Walbro -- Sold
'94 TW | R.I.P.
tahiti350
Third Gear
Posts: 874
Joined: Fri Feb 03, 2006 7:17 pm
Location: Spanaway/Tacoma, WA

Post by tahiti350 »

IF the knock sensor registers the knock, which it appears mine didn't
'90 Bermuda Blue L Wagon (Wife's),
Auto, AWD, Now with 275K + miles!



2005 Outback, 2.5 AWD (wife's new daily)
ericem
Fifth Gear
Posts: 3242
Joined: Mon Oct 16, 2006 9:44 pm
Location: Toronto,ON Canada

Post by ericem »

On a N/A car I think it doesn't affect it much. I remember on my N/A when I replaced the cracked knock sensor made no difference.
1993 Subaru Legacy L AWD Wagon R.I.P
1994 Subaru Legacy SS R.I.P :(
2004 Nissan Titan LE 4X4
2007 Subaru Legacy GT :)
Legacy777
Site Admin
Site Admin
Posts: 27889
Joined: Tue Oct 15, 2002 11:37 am
Location: Houston, Tx
Contact:

Post by Legacy777 »

I can tell you when I was "testing" my knock sensor and trying to make it not as "sensitive" when I was non-turbo, it tweaked out and made the car run like poo. I had no power, and it threw a CEL.
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm
douglas vincent
Knowledgeable
Knowledgeable
Posts: 3336
Joined: Sun Apr 27, 2003 5:50 am
Location: OR, Portland
Contact:

Post by douglas vincent »

Poo don't run.....
Reddevil, Awaiting new heart, will it ever happen?
1990 wagon, EJ25 12.3 @ 116.5 FAST Family wagon getting new motor soon
1992 wagon, wifes daily, high compression
1992 Touring wagon, should I keep it?
Josh222
First Gear
Posts: 88
Joined: Sun Jun 17, 2007 4:47 pm
Location: Ontario, Canada
Contact:

Post by Josh222 »

douglas vincent wrote:Poo don't run.....
I'm sure if you ate some mcdonalds it will :mrgreen:
92 Touring Wagon Mica Black(sold)
99 Outback Limited(sold)
05 Outback XT Limited
Post Reply