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-   -   heard knocking on the way home - intermittent (http://legacygt.com/forums/showthread.php?t=180972)

dmp 03-01-2012 05:18 AM

heard knocking on the way home - intermittent
 
Coming home from work monday, pulling out of a gas station I heard a knock-sound akin to bad CV joints. Within a few seconds, the sound went away. I heard it twice more on the way home, each time sounding a couple seconds. After the third time the CEL illuminated. As I was approaching my driveway the oil light came on, but shut off when I made the right turn into the driveway. I added a little over half-quart of oil. Existing oil was clean. CELs show OCV problems. Sound hasn't happened while revving in the driveway, or driving up and down the 150-feet or so driveway.

Preparing for the worst - new shortblock? The clicking/knocking screamed 'rod' to me, except it wasn't happening all the time, AND the car had no decrease in power up until I heard the noise. Idle is perfect.

Thoughts? Ideas?

Max Capacity 03-01-2012 05:35 AM

Only 1/2 a quart of oil ? have you checked it since ?

The fix for the OCV cel is sometimes, to remove the banjo filter.

bmx045 03-01-2012 08:31 AM

no oil delivery!

scenario- you spun a bearing and now bearing material is clogging banjo filter(s) delivering to your turbo and avcs solenoid- this causes ocv codes since there is no oil being delivered to the avcs. if oil light came on, its too late. drain oil and inspect for metal flakes/shavings

dmp 03-01-2012 11:24 AM

Quote:

Originally Posted by Max Capacity (Post 3773260)
Only 1/2 a quart of oil ? have you checked it since ?

The fix for the OCV cel is sometimes, to remove the banjo filter.

Indeed - after I added the 1/2ish quart, oil was right at full line.

Quote:

Originally Posted by bmx045 (Post 3773494)
no oil delivery!

scenario- you spun a bearing and now bearing material is clogging banjo filter(s) delivering to your turbo and avcs solenoid- this causes ocv codes since there is no oil being delivered to the avcs. if oil light came on, its too late. drain oil and inspect for metal flakes/shavings

If I find no shavings/flakes?

bmx045 03-01-2012 11:55 AM

there's a strong chance you'll find material in the oil. the oil light comes on after damage is done

dmp 03-01-2012 12:16 PM

material means = spun bearings = means complete bottom-end rebuild = thousands? fwiw, when the oil light came on, there were no funny sounds - engine was running smoothly.

BarManBean 03-01-2012 12:21 PM

I hate these threads. Good luck OP, hope everything turns out alright. Keep us posted!

bmx045 03-01-2012 12:28 PM

well, you were low on oil and took a hard turn causing the oil to swish to the side of the pan causing a brief "no oil pressure" scenario, maybe it wasnt long enough without oil to do certain damage but i'd drain the oil and look at it to be sure. the cel can come from a brief lack of oil pressure as well

ClimberD@HexMods 03-01-2012 12:33 PM

I am under the impression that since the ECU does not log oil pressure, it has no idea whether you have oil pressure or not. The 2psi switch is wired directly to the gauge cluster light. Only the power steering pressure switch goes to the ECU.

bmx045 03-01-2012 12:38 PM

OCV cel for avcs gets triggered immediately once oil flow is occluded or lost

dmp 03-01-2012 12:39 PM

Quote:

Originally Posted by BarManBean (Post 3773932)
I hate these threads. Good luck OP, hope everything turns out alright. Keep us posted!

Thanks man. Considering fixing the car, trading it. :( Don't wanna...but...might buy something to leave stock. Mazdaspeed3, etc.

Quote:

Originally Posted by bmx045 (Post 3773942)
well, you were low on oil and took a hard turn causing the oil to swish to the side of the pan causing a brief "no oil pressure" scenario, maybe it wasnt long enough without oil to do certain damage but i'd drain the oil and look at it to be sure. the cel can come from a brief lack of oil pressure as well

Yeah - will drain the oil with a screen and magnet to look for or catch metal.

Quote:

Originally Posted by ClimberD@HexMods (Post 3773949)
I am under the impression that since the ECU does not log oil pressure, it has no idea whether you have oil pressure or not. The 2psi switch is wired directly to the gauge cluster light. Only the power steering pressure switch goes to the ECU.

...so what would that mean? - edit - so you're saying the CEL would come up from oil pressure? gotcha.

bmx045 03-01-2012 12:47 PM

1. a screen will not catch fine bearing material

2. bearing material is nonferrous

3. what Dave is saying is the cel is not because of the oil pressure light triggering, it's because of the avcs not getting oil. the cel "mechanism" doesn't know what the oil pressure is or if it even has any.

ClimberD@HexMods 03-01-2012 12:50 PM

I should have read your post completely before I responded. Shame on me.
Your question was answered by bmx045. AVCS is actuated by oil pressure, so no oil pressure = AVCS CEL.

Quote:

Originally Posted by dmp (Post 3773961)
...so what would that mean? - edit - so you're saying the CEL would come up from oil pressure? gotcha.

I am curious whether your oil pressure light came on at all. It is literally a basic pressure switch without ECU logic. Usually when it comes on, even if only for a second, it means you have a very serious problem. If yours did not come on, then oil pressure stayed above 2psi. Not necessarily enough to keep metal off metal, but you may have a chance.

As others have said, drain the oil and see what you get. One thing I notice on here is people will cold start the car after such an incident. That can be what actually kills the engine for good, since the metal in the oil is filtered when warm, but NOT when cold and the filter is in bypass mode. If there is metal in your oil pan, and you cold start, you're sucking it right into the motor. Anyways, good luck.

dmp 03-01-2012 12:59 PM

If a screen or mag can't capture the material, how should I find it?

bmx045 03-01-2012 01:01 PM

you can usually see reflections in the oil itself, or if you get some and smear it on a cookie sheet or something you can see little specks left behind as the oil runs down it


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