misfire and pinking :(

[DarkArt]

Right had my Rallye for a while and had the standard IAV valve and MAP sensor fail. The crank sensor failed rhe other day and they've all been replaced and its ran fine. Up until this morning. Noticed a slight misfire so grabbed a set of plugs and changed them tonight although I expected the coil pack (s) to be gone. Misfire is still there but now itsddeveloped some pinking literally straight after changing the plugs. Any suggestions guys?

[Eeyore]

Sorry if I'm being a bit thick but what is pinking? Never heard of it before.

And welcome to thrbforum seeing as you've only got one post. Introduce yourself in the newbies section and put a link to this thread to say you need help.

[Tom]

Its an old fashioned term, if you open the throttle up on something carb'd at low rpm theres this metallic tapping type sound, very quiet though, its called pinking.

[si_batt]

Pinking is abnormal combustion, it's usually caused by excessive cylinder pressure, which can result from high compression ratio and advanced spark timing. It's strange that your car is doing this, the knock sensor should prevent this. Is the knock sensor plugged in and working? Presumably your car pinks at full load and mid engine speed? What fuel are you using?

[Eeyore]

Interesting term. Cheers for filling me in lads!

[DarkArt]

Its under full load yes. Its been fine up until I changed the plugs. Knock sensor is plugged in.

I'll introduce myself. Thanks for the tip.

[si_batt]

Ah, what spark plugs did you use? If you used ones with too hot a grade this can lead to pinking.

---

Try putting the old plugs back in maybe and see if it goes away?

[DarkArt]

NGK BKR6EK. It had iridiums in it and I've just replaced them with normal ones BUT its been chipped, the thought also crossed my mind as it happened as soon as the plugs went in.

[RetroPug]

How tightly did you do up the plugs?
Are you sure that it isn't the plug moving as this can also make a tapping noise.

[DarkArt]

Just hand tight and then nipped. I'll double check everything tomorrow and maybe put the old plugs back in and see if the noise/pinking clears. Need to hunt down a coil pack to now.

[c.gerrard]

Cheers for filling me in lads!

Giggidy

[DarkArt]

Well a little update. Jumped in this morning when it was cold and it didn't pink, only does it when it's warm. Ordered a set of coil packs and going to put a set of iridiums back in it.

[RetroPug]

They have instructions on the pack, you need to turn them to the point that you've crushed the crushable copper washer properly. I can't remember how many turns this was but it is on there.

[si_batt]

That makes sense that it only does it when warm. Sounds like a good idea to try the iridium plugs again.

[DarkArt]

Appreciate the advice man but i'm an ex technician. The plugs are plenty tight enough. Thank you though.

Yeah new coils are inbound so i'll put some Iridiums back in with those. i just wonder as its been chipped whether its a little picky due to the map.

[DarkArt]

Sorry if that reads really shitty Retro. Not meant that way.

[si_batt]

Yeah it makes sense that with a remap it might be a bit picky. What / whose remap do you have just out of interest?

[DarkArt]

No idea man. It was done before I owned it by Shepherd Motors in Great Baddow. Might go and find out. One thing I do know is its a lot of fun!

[Ruan]

Is it pinking only under heavy acceleration or any certain conditions?

[DarkArt]

If I drive like a granny its fine but if I start loading it up once warm she pinks.

[RetroPug]

Sorry if that reads really shitty Retro. Not meant that way.

No worries just checking man.

[jammapic]

Are you sure the knock sensor is ok?

It really should pull all the timing out of it as soon as it detects knock, before you even hear it.

It could be the map is bad, and as such it's got too much timing in it... hard to say.

JP

[DarkArt]

Right I chucked the old plugs and a new set of coil packs on tonight and no change. Pulled plugs off the injectors and there wasn't one that made it stay the same. They all dropped a cylinder off blipped the throttle and she's tapping/slapping like a good'un. Poor old girl has done a 147,000 miles and forced herself into retirement. As much as I love its not worth me pulling her apart to see whats up. Definitely sounds like somethings let go somewhere though. I don't have the time or space to get her back to rights with a new job looming and a 7 month old boy so I'll be breaking her piece by peice as and when I can. Whats the going rate for braking a Rallye nowadays? She's got a chipped ECU which I'll get more info on, upgraded rear ARB, bilstein shocks all the way round (possibly standard) and 16" Compomotive MO2's.
sad day

[9Freedman9]

Isn't pinking where the piston rattles up the side of the bore? In my experience it's not normally a tappy noise, more quieter but high pitched if that makes sense?

[Daniel306]

No, read this http://en.wikipedia.org/wiki/Engine_knocking