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low rpm knock with e85

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Old Aug 13, 2009, 07:20 PM
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low rpm knock with e85

weird phenomenon.

Evo VIII on e85 getting high knock counts, with evoscan in low rpms 2800-3200 rpms....

Above 3200 I can rip on the car without a count... below and gradually rises.

Tried changing the timing, both down then up. Nothing happened, same response, Leaned it out a bit, and nothing happened. back to timing and nothing.

I'm just stumped... Only other issue I hear is my power steering pump, which wines like a dying bird... thought that could be setting it off but I won't know till I replace it.

Got M2's, 16g, and fullrace header.
Old Aug 13, 2009, 07:22 PM
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hermmmm
Old Aug 13, 2009, 08:43 PM
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Sounds like classic phantom knock to me.
Old Aug 13, 2009, 09:01 PM
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Well I've been reading threads for the last two hours and could be a number of issues.

Here's just a few mechanical issues that could be the problem:

- Cam not lined up properaly
- Jumped timing - valve train
- clutch, exhaust, header vibrating
Old Aug 13, 2009, 09:37 PM
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If he jumped timing then he'd have bigger issues then low RPm knock....more then likely something is setting the knock count off and at lower RPM's your cams might cause it vibrate more then normal (You might be on to something with the power steering making noise). If your exhause is hitting something and making a metal on metal sound I've seen that give phantom knock as well.

What count? 2-3?
Old Aug 14, 2009, 07:12 AM
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count goes all over the place, sometimes hitting as high as 30 counts. This only happens between 2900 - and 3300 rpms. It's a very small narrow band.

I definitely might have rattling issues with my exhaust, I know it almost if not does vibrated against my cusco underbrace. I've also been told it could be from my fullrace headers. Clutch is getting old and there's more chatter than before.
Old Aug 15, 2009, 11:29 PM
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Are you throwing a P0300 code at all?
Old Aug 17, 2009, 10:46 AM
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I'm not throwing any codes at all.

So weird, it only shows knock at really low load... and only in the 3000 - 3500 rpm range.

today on my way to work I'm cruising in 5th gear and it still does it around 3400 rpms.

Replaced my spark plugs this wkend, and no signs on the plugs of detonation...

Thinking of turning down my knock sensor sensitivity in this region...
Old Aug 17, 2009, 12:46 PM
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Originally Posted by sdfontanini
I'm not throwing any codes at all.

So weird, it only shows knock at really low load... and only in the 3000 - 3500 rpm range.

today on my way to work I'm cruising in 5th gear and it still does it around 3400 rpms.

Replaced my spark plugs this wkend, and no signs on the plugs of detonation...

Thinking of turning down my knock sensor sensitivity in this region...
Thats what i ended up doing I think the cams i installed were the final straw in the knock sensor at that range.
Old Aug 17, 2009, 01:59 PM
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So I turned down the knock sensor sensitivity. Now only seeing maybe 1 count of knock in the lower rpms. Car pulls amazing, no more falling on it's face. Like you Roadspike, I'm thinking my M2 cams are what's setting it off.
Old Aug 17, 2009, 07:36 PM
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I had the same issue. It is phantom knock (assuming your mapping is correct). If you are able to adjust knock tables, then that would help.
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