Is My Fiesta Pinking? Do They Still Do That?

[leederbyshire]

I thought pinking/knocking was a thing of the past, thanks to computer-controlled cars, but my 2003 Fiesta Zetec sounds like it's doing just that. An annoying rattling that it makes under load. It doesn't do it every day, but some days it seems to do it all the time, even at 70mph. I'd have thought a pinking car would not be able to reach 70, or even do it at that speed. So it could just be something bouncing about.

Wouldn't the knock sensor be taking care of it? I'm not getting any failure codes to suggest there's anything wrong with it.

[FezDan]

I think pinking is what you get when your engine timing is too far advanced. on newer cars there is usually a sensor that detects pinking and adjusts the ignition timing so you dont get it.

Pinking or pre-ignition can sound like leaves rustling in the exhaust headers through to a tinkling noise behind the dashboard. When it gets bad it can sound like tapping and then it's becomes detonation and you may hear knocking noises and that's serious.

have just pulled the above comments off another forum! not sure if that will help but I think if you had an issue with the knock sensor you'd definitely get a fault code coming up on the diagnostics

[leederbyshire]

Hi Daniel. Thanks for the reply. I did read elsewhere that advanced timing would cause it. In fact, I've had enough older car and bikes to know that if I could !Removed! the timing, I'd at least have a better idea if it was pinking, or just some part rattling somewhere. But you don't get the chance to do this any more, so I don't know how it could become advanced. I assume the computer has an advance curve that is correct, and you're stuck with it.

It does sound more like something rattling about, but I've grabbed and shaken just about everything under the bonnet without finding anything. The drop links look about the right size and length to make the sound I hear, so I'll have to jack it up and check them.

[FezDan]

Nightmare! nothing worse than an annoying knock or rattle that you cant locate. My Mk 5 ZS has the strangest 'bubbling' noise on start up which I think is coming from the air filter (oversized, badly fitted, aftermarket cone) which was on the car when I bought it, but for the life of me I cant get it to stop! have taken the filter off, cleaned it, everything! As it didn't seem to be affecting the performance I ended up giving up and dealing with it!

[leederbyshire]

I've read that cars with automatic temperature control air conditioning can do that. Never experienced it myself, though. If it really does sound like bubbling, then it might be an airlock in the heater pipes. Or something. I'm sure you've already asked about it.

[FezDan]

I've had it down my mates garage and everything! Its a mystery. I used to be a member on ZSOC and no one there had ever experienced it. Based on that, i'm pretty convinced its to do with the cone filter, thinking maybe changing it back to a panel filter might solve the problem but as i've just bought a mk6 fiesta i'll leave that down to the next lucky owner to work it out!

[FOCA]

If it is actually pinking it can be caused by many things -

1 -

Often, an older design of engine is used in a newer car, to meet more modern emmision requirements and to make the engine economical (which can often be contradictory), emmision conttrol hardware and an emmision/ ecomomy serup is "stuck" on the older engine , along with taller gearing (for economy) - the cars often get bigger/ heavier on each mark/ facelift

The taller gearing means the engine is offten "chugging" up hills at low revs and the economy emmision control stuff (read junk) is affecting the way the car runs for example reducing the amount of fuel injected or making the EGR valve open (so the car is running on burnt exhaust gasses rather than clean air)

So its not one thing, but all these things coming together (the tall gearing, the extra weight, thbe extra emmision control hardware, the emmision/ economy ECU setup etc and other things, like -

2 -

the combustion chamber on a car can get coked up, - when the combustion chamber is coked up, the contamination can "glow" hot and cause pinking/ detonation, the coking up can be due to simply a high milage, the car being driven sedately or a rich mixture (or these together) an old/ choked air filter can cause a rich mixture (too much fuel/ not enough air)

3 -

Ironically, traditionaly too lean a mixture can cause pinking/ detonation, or fuel of too low an octane or timing out etc

4 -

the condition/ colour of the spark plugs can be checked to see if the engine is running too rich/ lean (an old school mechanic/ tuner can tell a lot about the car from the plugs)

5 -

An open cone filter (eg k&n) can draw warm, underbonnet air, causing pinking/ detonation

There may be other noises that sound like pinking -

A heatshield may have come loose and is rattling

the CAT element may have come loose and is rattling inside the exhaust

[leederbyshire]

Thanks, FOCA. You've given me a few things to think about. Someone already suggested to me that it might be the manicat breaking up, and that if you thump it hard enough, you can hear a broken one rattle. But I heard nothing when I tried it. I think that would also affect the MOT emissions reading, too.

The car does tend to get driven sedately. School run, and all that. I wish I could see inside the combustion chamber, but I'm reluctant to take the head off. I changed the timing belt last weekend, and that was a bad enough job. I think I'll try one of those cheap endoscopes.

[FOCA]

Thanks, FOCA. You've given me a few things to think about. Someone already suggested to me that it might be the manicat breaking up, and that if you thump it hard enough, you can hear a broken one rattle. But I heard nothing when I tried it. I think that would also affect the MOT emissions reading, too.

The car does tend to get driven sedately. School run, and all that. I wish I could see inside the combustion chamber, but I'm reluctant to take the head off. I changed the timing belt last weekend, and that was a bad enough job. I think I'll try one of those cheap endoscopes.

Whip the plugs out, photograph them (the ends that go in the engine :) , in good light) and stick he photos on the thread - might give an indication of how the car is running

A service and a good old "italian tune up" might help, a detergent type fuel additive designed to clean off the carbon might help, or a premium fuel with detergent in it

if its running rich the higher octane fuel may make things worse but a fresh air filter will make things better

conversly if its running lean the higher octane fuel will help and the fresh ait filter may make things worse

On a modern car the mixture, ignition advance etc is Controlled by the ECU - it is not easily changed

Another potential fault not mentioned is the crankcase breather hoses can perish/ split, or the PCV valve can gum up/ stick - drawing air that is not measured by the MAF.

[John_D]

If the car is used mainly for shortish runs, a build ip of carbon can ossure in the cylinder head; even today with advanced fuels. The carbon build up can glow red hot causing pre-ignition. One trick we used to get rid of this without taking the head off was to use Redex. (Can you still get this??). We used to pour some into the carburettor (sp) and run the engine. This was done preferably away from civilisation as the ensuing white smoke could cover the neibourhood. As we no longer have carburetors just take out each plug and pour a few drops into the combustion chamber, then run the engine. As has been mentioned above, pinking (sounds like breaking glass) can be caused by ignition too advanced, low fuel RON, etc etc as well as what I mentioned. I would suggest getting it seen to as prolonged pincking can easily destroy the engine. You can determine where the sound is coming from with the old fashioned screwdriver test ! Take a longish screwdriver, place the metal end on the suspected part of the engine and press your ear to the handle end. (Do NOT touch the plugs! )

(P.S. Previously I owned a garage specialising in tuning Triumph TR2 and 3s) :)

[John_D]

This photo may asist in checking the plugs.

[FOCA]

If the car is used mainly for shortish runs, a build ip of carbon can ossure in the cylinder head; even today with advanced fuels. The carbon build up can glow red hot causing pre-ignition. One trick we used to get rid of this without taking the head off was to use Redex. (Can you still get this??). We used to pour some into the carburettor (sp) and run the engine. This was done preferably away from civilisation as the ensuing white smoke could cover the neibourhood. As we no longer have carburetors just take out each plug and pour a few drops into the combustion chamber, then run the engine. As has been mentioned above, pinking (sounds like breaking glass) can be caused by ignition too advanced, low fuel RON, etc etc as well as what I mentioned. I would suggest getting it seen to as prolonged pincking can easily destroy the engine. You can determine where the sound is coming from with the old fashioned screwdriver test ! Take a longish screwdriver, place the metal end on the suspected part of the engine and press your ear to the handle end. (Do NOT touch the plugs! )

(P.S. Previously I owned a garage specialising in tuning Triumph TR2 and 3s) :)

Yes, you can still get Redex- but its not just one product, but a range of products -

http://www.halfords.com/webapp/wcs/stores/servlet/branddisplay_storeId_10001_catalogId_10151_categoryId_165739_langId_-1_MFName_Redex

No neet to drop the redex (petrol fuel additive) down the plugholes (perhaps this would decoke the chambers better!) just add it to the fuel tank

As i suggested in a previous post, a detergent-type fuel additive or premium fuel might help

Another option (expensive, though) is to terraclean the engine - that should decoke it without having to take the head off

In my racing days i used to strip the engine(s) down between every meeting, the combustion chambers (and piston tops) would be polished till they shone - new plugs were fitted every meeting - different grade (platinum tipped racing plugs were used and a big box of different sized jets, the condition/ richness/ leanness/ timing of the engine was determined by the sound, the lap times, feedback from the driver (eg driver asked - does it pull better out of the corners, what is it like at the top end? ) and the colour of the plugs, , - the engine may have been run leaner/ richer to get an advantage- this may have been compromised for at the start or end of the race, or for top end, or it was run "close to the ragged edge" for qualifying etc - it was a bit of a "black art" often taking years of experience/ practice - only the tuners/ race engineers judged these things, in the same way, best to have people who know how to read plugs to do it, than a layman, from a chart in case they mis-interpret it

[leederbyshire]

Thanks for the suggestions. The plugs usually look okay to me (they get changed each couple of years, so there isn't much time for much of a deposit to build up). I'm used to checking for the nut-brown colour since my old motorbike days, so I know it's a good indicator. I ordered one of those cheap endoscopes of eBay - when it arrives, I'll see if I can get a good image of the piston crowns, and post something here.

To John_D, I have often used wooden sticks and large rubber tubes to find engine noises. The problem here, though, is that it only does it under load, and even then, not always. We went out for a long run yesterday, and it didn't do it at all. Other times, it starts doing it straight away. I've never noticed any pattern to it.

[John_D]

Hope you get it sorted Lee, strange noises in motors arfe always a nuisance. Especially when they just cone and go.

[leederbyshire]

Well, the endoscope arrived. Amazing what you can get for less than a tenner, although I'll need to work on the brightness control. Plugs look okay. The lights from the camera make it look brighter than it is. If anything, though, it looks a little hot.

Piston crowns are a bit messy, but it _is_ over ten years old. Again, this is much lighter than it should be. Looking down the plug hole, it is clearly black.

I'll see if pouring Redex in clears it at all. A bit more worrying is that cyls 3 and 4 have wet spots on the crown. Having said that, the engine was still hot. Maybe it is a drip of fuel? It does not appear to burn oil.

[john s smith]

1999 fiesta started pinking . Changed air filter and cleaned plugs and used higher quality petrol . seems to have stopped the pinking .

[Bobr]

Would using Redex not affect the catalytic converter?

[Jethro_Tull]

Nope.

[Bobr]

46 minutes ago, Jethro_Tull said:

Nope.

I just found this and, as Redex is an oil:  

Blue smoke from your tailpipes may be the first visual clue that your piston rings, valve seals, or valve guides are allowing oil to burn inside of your engine. To get to those tailpipes, the oil has to pass through the catalytic converter. Oil-fouling of the cat.

[Jethro_Tull]

Degree in automitive science and engineering. Provided your car is otherwise in good order, it will do zero harm.  The unburned fuel that passes through your exhaust with every piston stroke is an oil distillate, and does no harm.

Provided they're not downright abused cats are far more robust than most people understand them to be 

[Blatto]

Just another thing that might be worth checking.

Back in the Mid 1990's I had a MKII Toyota MR2 which developed a "pinking" like sound. Had the engine checked over and nothing found. Seemed to happen at certain speeds on motorways and more noticeable going up the ramps in a multi-storey car park (maybe amplified by the close proximity to the concrete walls). On some occasions it would go away for a few weeks then return (sods law that happened during the period I had it booked in) . Turned out to be the engine brackets used for lifting the engine out (not sure what their technical name is). One of the bolts holding it to the engine was very slightly loose and it allowed the bracket to rattle a little bit but only under certain conditions i.e certain revs and if on a slope, hence the car park ramp effect.

Might be worth checking for something simple like that, though it wasn't easy to tell as the bracket was only very slightly loose and that was only noticed by accident when I was trying to change my oil filter.

 

 

 

 

[Jethro_Tull]

Tidying up one of my garages today found 2 x bottles of petrol Redex.

"This product is safe to use with catalytic converters", says the label.  Excellent, so chucked one each in each in the Westie and the Fusion.

[pinkerman]

I was absolutely convinced that I had a pinking problem with my 2008 Fiesta 1.25 at low revs, particularly evident when it was cold outside but, daft as it may seem, after trying to solve the problem over a period of years, by replacing several "likely" parts and getting nowhere, I found that the pinking sound was actually caused by micro-slippage of the auxiliary belt with torque pulsations transmitted through the crank pulley.  Replacing the stretch belt cured the problem completely !!   It still sounds daft, but that's what it was.  I hope that it works for you.