GVR-4 Bad knock sensor or phantom knock?

[Bmxr152]

My car has a huge loss of power at 20% throttle or more. As you can see in the Datalog below the rpm is staying about the same but the knock is going up whenever the throttle goes up, thus giving me no timing. does this rule out phantom knock since the pm is pretty much the same while the knock is shooting up.

http://www.cardomain.com/member_pag...ges/2/web/2282000-2282999/2282369_24_full.jpg

 

[DSM90AWD]

That looks like a textbook case of PK to me which is super-high spikes of knock sums on initial tip-in of the throttle. Have you replaced your Knock Sensor yet? The internal knock sensor's mic is insulated with a tar-like goo that over time will leak out possibly making it more sensitive to engine vibrations.

Other things to check: make sure your LTFTs are near 100%, boost leak test your intake, make sure base timing is set to 5*BTDC, perform a cylinder compression test, verify that no CELs are present and that noise from "sloppy" engine mounts, worn/loose exhaust hangers..etc are not the culprit.

I had PK for years (even after checking all the above) and ended up resorting to a DSMChips EPROM which uses code to ignore knock signals below vertain throttle points and RPM (similar to the stock code in the 2G ECUs which rarely have this issue). DSMLink also has this feature but is user-adjustable

 

[steve]

If you want to tell between real and phantom knock you have a couple of options.
Lower your boost and/or run race gas.
Phantom knock will remain.

What is your base timing right now?
How much boost are you running.
What octane gas are you using.

Your link isn't working.

Steve

 

[Bmxr152]

I'm running 91 octane and it won't boost past 10 and base timing is 8 degrees.

I mean when the knock is going up the RPMs aren't and therefore nothing could really be vibrating, so could that mean I have a bad sensor?

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[steve]

Have you checked the sensor? If it's original it overdue for replacement.

That timing advance curve looks suspect. It looks like doesn't go below 16*
I assume you know that your base timing should be 5* BTDC
What does your TPS read at idle.

Steve

 

[Bmxr152]

It reads 10% throttle at idle. this is what it was reading a day earlier...

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any suggestions now?

 

[Newlogics]

Timing curve looks normal considering throttle and knock situation.

It's def. not a pre-detonation (your part-throttle knock segment confirms that). However, you may have damaged valvetrain or piston skirts (wost-case scenario).

 

[Bmxr152]

this is on a brand new engine exactly 143 miles

how could it change so derastically from 1 day to the next

 

[Newlogics]

how could it change so derastically from 1 day to the next

I'd be more surprized if this happened to the engine that's been broken in already.

Anywya, take your timign belt off and make sure all timing marks are dead on. Sometimes miss-alignment of cam timing marks leads to being 1/2 tooth off on the crank sproket, which causes a lot of phantom(mechanical) knock.

 

[Bmxr152]

it was off BIG TIME before and then i fixed it. Before the cams wernt lined up or the crank lined up! This was on the 1st day of break in, and when all this knock happened was like the week after. Have you ever seen a car go from having no knock one day to have A LOT of knock the next day? Im going to repace my sensor i think, but its got me thinking somthing internally might have gone wrong. Oh and the timing was set