carbon buildup causing pinking

[Ady]

at a loss with my 1.8 hlx garage is saying he has tried the diagnostic and all sensors and computer is saying everything is ok,he said he doesen't want to look into it any further as it's just trial and error changing components to see what solves the problem (doesen't sound very promising) and be costly due to labour time etc etc,i was told by another mechanic is basically it's got to be carbon buildup what's causing the pinking because he said everything is controlled by ecu, it's an N 1996 has only done 38000 miles and the last 12 months has been subjected to very short journeys from cold ie 5 mins then switched off a few times a day,could it really be carbon buildup even though it's quitel low mileage for it's year? if so what would a approx charge for decarbonising an engine typically?

 

[Tom]

It would have to be FULL of carbon and a good thrash would clear it no problems.

A de-carbon (which is a waste of time IMHO) involves taking the head off which then means you need to have the head skimmed otherwise it won't fit right. You are looking at a LARGE sum of money.

Question: are your spark plugs black or brown at the business end?

 

[Ady]

hi tom

the plugs are showing perfect tan brown condition i changed the plugs last week for the same type NGKBKREK6 i they are...

 

[Anonymous]

Ady
Go to the `midland performance centre` website and click on Powerboost

Pete

 

[SchumaniaC]

Re: Re: carbon buildup causing pinking

Can someone explain to me about this carbon build up? How does this come about?

If Tom's solution is right, then my engine is carbon free coz I redline quite often.

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The Bravo...different day, different sh!t

 

[Tom]

Re: Re: Re: carbon buildup causing pinking

The carbon gets there from not quite complete combustion of the fuel, it never ever burns 100%.

Generally the carbon buildup is a good thing, it provides an insulating layer between the hot gasses and the engine and helps keep the gasses hotter giving better power. A brand new engine will run slightly lower in power until its got a good layer of carbon.

Now, if you have alot of oil in the cylinder or far too much fuel you basically get soot buildup. This soot will glow red hot and in old carb'd cars would cause dieseling and run on where the engine would keep going after you turned it off.

If you have REALLY bad carbon buildup then you can get pinking but its rare as it burns off very quickly when the engine is working correctly and under power.

 

[Tom]

Re: Re: Re: carbon buildup causing pinking

Just as a PS, I think his problem is not carbon buildup, its not pinking even. The symptoms sound more like a worn big end bearing which does sound very similar in noise.

People used to get their engines de-carboned but modern petrols, modern fuel injection systems etc have totally eliminated the need for that. If someone takes the head off a modern alloy 16valver and is not 110% careful about the reassembly you will have no end of problems.

I think he should get someone to take the sump off and plastiguage the mains, much cheaper, simpler and far less dangerous than taking the head off.

 

[Martin]

Re: Re: Re: Re: carbon buildup causing pinking

I had big end problems in my first car (a Capri, no sniggering at the back).
The noise does sorta sound like pinking, as you rev the engine the noise goes away, so being the idjut of a 17 year old I just used to drive it at high revs everywhere (as nova/corsa drivers do these days) and eventually the engine siezed Outside a nightclub as well, oh the shame LOL

 

[Tom]

Re: Re: Re: Re: Re: carbon buildup causing pinking

DOH!!!

 

[SchumaniaC]

Re: Re: Re: Re: carbon buildup causing pinking

Tom, thanks for the interesting lecture. You should be up there with the likes of Paolo Martinelli, Mario Thiessen and Mario Illien!!!

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The Bravo...different day, different sh!t

 

[Tom]

Re: Re: Re: Re: Re: carbon buildup causing pinking

I wish, I've just read toooo much

 

[Anonymous]

Re: Re: carbon buildup causing pinking

Tom

After approximately 1600 cold starts and only 5 minutes running, the very best of oils and fuel could not prevent carbon build-up. It only needs a small spot of carbon to glow red hot and cause pre-ignition, i.e. pinking.

Pete

 

[Tom]

Re: Re: Re: carbon buildup causing pinking

Yeah but the plugs would be black, not brown.

I'd put money on you being quite supprised how much carbon is in a 'good' engine.

 

[ady]

hmm

tom not to sound patronising but i've had 2 mechanics look at it and they it is definately not main bearing or any sort of bearings,so i'm stumped

 

[Tom]

Re: hmm

They do sound very similar, its worth a check.

 

[Anonymous]

Re: hmm

Ady, I`ve already replied. If you go to the `Midland Performance Centre` website, you can read about Powerboost which gets rid of carbon by spraying the aerosol into your air intake.

Pete

 

[Ady]

thx

i'll go tak a look at that right now.

 

[Ady]

where would i use this product exactly

is this stuff just sprayed in the air filter housing after taking the air filter out? won't this damage the air flow meter?

 

[Anonymous]

Re: where would i use this product exactly

Shouldn`t do. If you e-mail them they`ll tell you.(or give them a bell)

Pete