engine knock

[207gti]

car is suffering from engine knock now and again quite badly, whats best way to eliminate this? water injection/bigger intercooler?

thanks

[Defcon5]

Is it modified at all?

[207gti]

yeh power module fitted and induction kit, had the knock issue before it was modified also.

[Defcon5]

Surely its still under warranty? Whip off the aftermarket parts and dump it at the nearest pug dealer.


Can you describe the problem any further?

[207gti]

yeh its been to dealers and they wanting the module off, but company i got module from assures me its not that as it was happening before it.

power comes and goes, sometimes its there and next time put foot down its now, feels like its jumping/hesitating. had knock sensor replaced last september.

timing has been reset for another issue.

[Defcon5]

Faulty coil pack maybe? I have no experience of new french metal though.

Are you getting any ECU errors?

[stevieturbo]

Are you using the correct fuel ?

The engine should NEVER see detonation. If it is, get it fixed by a competent tuner/mechanic immediately before you destroy the engine.

And why on earth would you try and tune it further, if it already had such a problem ??

How are you determining that it is detonation ?

[Defcon5]

I dont think the OP actually has proper knock, It would already be knackered wouldnt it?

[207gti]

intermittent fault recorded but now says permanent, no fault code though.

shell v power used.

knock sensor was replaced and fixed the fault last sept but has returned.

Edited by 207gti on Sunday 10th May 17:14

[stevieturbo]

207gti said:

intermittent fault recorded but now says permanent, no fault code though.

shell v power used.

knock sensor was replaced and fixed the fault last sept but has returned.

Edited by 207gti on Sunday 10th May 17:14

SO clarify.

Is there detonation or not ???


Or is it just a faulty knock sensor ? Very big difference.

[207gti]

detonation as misfire? i would say a bit yeh

[GreenV8S]

207gti said:

detonation as misfire? i would say a bit yeh

Detonation and misfiring are completely different things. If you have a misfire there's definitely something wrong. It is a different problem to detonation, but may be related. For example, running lean can cause both symptoms.

[207gti]

bout 2 months ago timing was way out, fault codes for running too lean and too rich, work that out lol

[GreenV8S]

207gti said:

bout 2 months ago timing was way out, fault codes for running too lean and too rich, work that out lol

Completely possible. Assuming that the fault codes are latched, it could be running too lean at some times and too rich at others. You can even get both symptoms at the same time if the cylinders are not all behaving the same. Even more confusing, a rich misfire will leave excess exhaust gas oxygen which will result in a lean reading.

[Defcon5]

Im going to guess faulty coil pack is causing misfire under load

[stevieturbo]

207gti said:

detonation as misfire? i would say a bit yeh

So clearly you dont know what knock/detonation is.

Its always difficult to diagnose problems over the net...and this is part of the reason. When someone describes a totally different problem, than is actually happening.

[Vixpy1]

Is it on a MAF ?

[207gti]

must be great to know it all, apologies for not knowing it all,

think will go elsewhere and get assistance from folk who wanna help.

[Pigeon]

207gti said:

knock sensor was replaced and fixed the fault last sept but has returned.

Is that ALL that was done then? Old sensor off, new one on, and that single operation stopped it playing up... until now?

That suggests to me that either it's eaten the replacement knock sensor, or there is a bad connection - corroded or loose connector perhaps - in the wiring to the knock sensor, and the wiggling of the wiring involved in replacing the sensor improved the connection sufficiently for it to work for a few more months.

[Zad]

Running lean / rich. Hmm. Have you checked the throttle potentiometer and/or air mass sensor if it has them? They can fail without giving a fault code.