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Riding Rough - Small Knock In Engine

SKITTLES

By SKITTLES,
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SKITTLES Experienced

SKITTLES

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I thought it was just the spark plugs, because it's what fixed the problem in my Excel, but I've changed them and it's still got a bit of a knock in it.

The only way to describe it is a misfire. It feels like the engine has a slight knock whilst idle. It's only very faint, and there's no sounds other than a faint clunk.

I'm going to check out the coil packs tonight if I get a chance, any cracks or the like I'll seal up with silicon.

Other than that, I'm lost for ideas. It's comparable to having a borked spark plug I guess is an accurate description..

Edit; I have a S2 R33 with the RB25DE, yes non-turbo.

Edited by SKITTLES
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SKITTLES Experienced

SKITTLES

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lol hopefully you fix your problem skittles, ive had the exact same issue and i just cant fix it...

Did you try the coil packs?

I once had a mate who had a knock in his engine, and he ended up having to sell because it was something that he couldn't fix / was damaging or something like that. But he couldn't fix it :S

mad082 Grand Master

mad082

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Posted

could be an issue with an injector not closing (or opening) properly, or not spraying properly/evenly and at idle the AFR of 1 or 2 cylinders at idle isn't ideal, but at higher rpm it is ok due to higher fuel pressure and cylinder temps.

if you car is a series 1 then it may also be linked to the ignitor pack, or it could also be linked to lower compression in 1 cylinder. this is where a consult cable can be quite useful as with some programs you can individually turn off cylinders to see if any are weaker than others. if turning off 1 cylinder makes less difference than the others then you know that is where the problem is and can look closer at that. if you do a compression test and find that it is close to others then you know the issue is either spark or fuel related.

one other possible cause is the idle adjustment. i have seen cars where altering the idle screw can actually induce a slight miss. again this is where the base idle mode of a consult program comes in handy, however putting the car into base idle mode without it is relatively simple.

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