Running on 3 after big bang and now idles at 2.5k?! :(

[DannyR]

As above really, went into third gear followed by a bang, sounded like exhaust blowing.

Opened bonnet, running on three, knocking coming from first cylinder chamber I think, not really tested it.

Hoping something like coil pack, leads etc... But the knocking which sounds like a valve hitting is scaring me car still runs and drives fine just noisy and a bit sluggish

Any ideas?

 

[Dave..]

errr... I wouldn't be driving that.

 

[Laine_16v]

blown a spark plug out?

 

[DannyR]

Belts not slipped or anything though so wouldn't think valve would just snap or let go =\

It works fine it's still quite pokey as I took it as far as I could, if it goes bang it goes bang, but it easily got up to 70, bit slower than normal but it did it and sat there fine?

 

[DannyR]

blown a spark plug out?

Will get plenum off tomorrow night and check plug after I've found out which chamber is at fault!

 

[Laine_16v]

Your going to need to do some more diagnosing, does the engine sound consistent on cranking? (unplug coil pack and crank the engine for a bit), if the engine has physically dropped compression in a cylinder you will hear uneven cranking.

Other than that check plugs and leads.

I would be worried about the "bang" though, as it sugests mechanical failure somewhere.

 

[MicKPM]

blown a spark plug out?

+1

A few other things to check for are check to see if the MAP Sensor and Air Temp Sensor has blown out of the inlet. The injectors on the F4R are really flimsy and when damaged can fuel incorrectly... the resulting overfuel causes detonation on the wasted spark and so blows these sensors out!

 

[DannyR]

Yea the bang is a wonder and it still pops and bangs inside the engine :S So could be an exhaust valve jammed but because of the high idle thinking an inlet valve maybe jammed down?! I dunno really, like I say I left it for a little bit and come back to it later, sometimes revs drop to 1k and it idles on all four sounding fine :s

 

[Greeny.]

+1

A few other things to check for are check to see if the MAP Sensor and Air Temp Sensor has blown out of the inlet. The injectors on the F4R are really flimsy and when damaged can fuel incorrectly... the resulting overfuel causes detonation on the wasted spark and so blows these sensors out!

Never knew that but one of mine just failed

 

[DannyR]

Oooh I didn't check sensors and could explain high idle, but other symptoms didnt match the sensor being blown out :S

 

[sideways danny]

high idle is consistent with a vacuum leak, so a sensor being blown out of a reasonable theory

 

[MicKPM]

That and the audible "bang" you heard also. Theyre so easy to check to as it could be something else.

 

[T.Trophy]

Danny is any Clio safe in your hands?

 

[DannyR]

Apparently not lol!

Another possiblity is spun shell

 

[DannyR]

Apparently not lol!

Another possiblity is spun shell