Riding Rough - Small Knock In Engine

[SKITTLES]

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 December 13, 2010 by SKITTLES

[mad082]

it will more than likely be your coil packs. they may be fine at high load, etc and not have a miss at all, but often as they get older you can get the slightest little miss at idle.

[SKITTLES]

I'm hoping your signatures right, Marc.

I'll have check over it at home tonight (if I can keep my eyes open)

[ClutchBurndout-:(]

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

[SKITTLES]

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

[ClutchBurndout-:(]

yea i changed the coils, i fear its something more serious, oh well ill fix it when the time comes

[mad082]

yea i changed the coils, i fear its something more serious, oh well ill fix it when the time comes

you tried having your injectors cleaned?

[ClutchBurndout-:(]

not externally no, she runs well when giving it a squirt though

[mad082]

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.

[ClutchBurndout-:(]

hold on, base idle mode? i have the consult and the program that came with it, am i missing some program?

[mad082]

i'm not sure if the ecutalk program has it, but i think either datascan or conzult have it.