Re: Corsa_funny noise

What do you mean by pinking? Pinking is just a noise, and it's certainly that. But I don't know what's causing it eg: is it too rich or too lean, or a crap spark? I reckon it's running too lean, but I don't know why.

Anyone I speak to just mumbles something about "ignition timing" being too far advanced, which is just getting annoying now - computers have been handling ignition timing for cars produced in the last 10 years or so. All my sensors are bolted into the right places.

Fuel filter is only a year old, but perhaps it's caught some gunk in it? Odd though that it happened straight after the head was rebuilt.

Similar noises, however, can be made by the engine running too rich, I think by the fuel mixture exploding in the exhaust manifold.

How do you know? If the mixture is too strong then fuel will escape into the exhaust manifold. When it hits the hot air in there, it will explode in exactly the same way as it would if it "pre-ignited" inside the combustion chamber - going "ping" !

When there's a leak at the front of the exhaust system it makes a ticking noise, especially under load. It's just the gas being forced out of a small hole. If the noise is more irregular and sounds like cutlery being bashed together it's probably pinking. Pinking's usually caused by overheating, advanced timing, lean mixture or carbon buildup.

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escape into the

explode in

the combustion

It wouldn't be regular and 'fast paced' as the OP said. More like an occasional and enormous BANG!, rather than a ping. Popularly known as a backfire. A build up of unburnt fuel in the exhaust pipe, can eventually reach a critical level, and then explode. Can split an exhaust pipe. Pinking caused by pre-ignition is totally different. The mixture is igniting too early, and the cyl pressure becomes too high, with the piston still rising. Not a very technical explanation but I'm sure you get the picture. Mike.

CV joint ? the load of hills/acceleration causes the problem ?

Why does this seem to happen so much with Corsas?

You need to give all the info here when you ask a question though. You asked a quetion without saying about the head being removed / re built. Did you do this ? Did a garage? Is the cam timing correct? Did it start as soon as the head was rebuilt?

Just trying to get all the facts an eliminate things.

Sorry, have just asked this a lot and got nowhere.

Head was rebuilt by a mechanic and a few days afterwards I noticed the pinking noise when the engine is under load and is very sluggish uphills.

Replaced the spark plugs (one did look a little odd) which fixed it for a bit, but the problem came back.

Replaced the HT leads, which did nothing.

Put Redex in the tank, perhaps the injectors are gunked up? This hasn't fixed it. The fuel filter is only a year old anyway.

On the A303 one night, it started raining, and suddenly I had a lot more power but the pinking noise was still there. This made me think it's a fuel or fuel mix problem, but I can't think why.

Do injectors need "re-tuning" when the head's rebuilt? Mine weren't.

Come to think of it I did have a problem with a leaky radiator which I noticed at the last minute the expansion tank was dropping rapidly below the cold level, so that might have led to the problem in overheating terms the engine did get very hot........and I think the problems did start close to one another....so that's not good.

So any links between the two if the level of the radiator got to a low point what sort of damage could we be looking at?

What engine is it? What age? Some of the older shape Corsa's with the 1.0

12V and 1.2 16V engines had a tendency to snap the catalytic converter mounting strap, which resulted in the type of noise you describe.

HTH

Anthony Remove eight from email to reply.

Put super unleaded in the thing it pinking.

If the noises are instead caused by fuel exploding in the exhaust manifold, then slow-burning super could make it worse.

When the head was replaced, the cam timing was right, wasn't it? Stupid question, but sounds like it's something since the head was off...that's my first guess.

Rain = Water = Better burn of fuel/air mixture.

I thought about that, but I'm not sure that if the valve timing was slightly off I'd get pinking. And if it was massively off, I'd have thought I'd be going nowhere.

Again, how would rain improve poor valve timing?

The valve timing could be just one tooth out; depending on which way, then it could just run (badly). The other way might bend a valve...

The ran shouldn't improve the cam timing, but it does make the fuel/air mixture burn better. Look up "water injection" on a google search, and see the improvements that can be had. They're onlt slight in normal cases, but sometimes outstanding results have been found.

Well it's a 99 1.2 16v.....as I said before I have looked underneath the car and didn't notice anything really but then again I wasn't checking the exhaust, might have to have another gander when I get time.

I think I'd know if it was a whole tooth out!

But suppose the camshaft was a fraction of a degree off?

How does the camshaft become a fraction of a degree off as you state??

Just a guess but I presume the top pulley has a slot for a woodruff key so it is therefore is fixed in relation to the camshaft.

Therefore the only option is for the whole pulley to be slightly out in relation to the position of the crankshaft.

I have know idea of the number of teeth / notches so have no idea what 1 represents in degrees. In my humble DIY mechanic mind I would suggest not shooting the messengers here. double check the cambelt timing in relation to the crankshaft.

It sounds to me like you are well down on power............not sure but I think a compression test would also show up if the cam to crankshaft timing was out as they wouldn't be fully closed at tdc....just a thought.

Just my 50p's worth.......have fun this weekend......