Pinking?

[R2D2]

My car had been developing what I thought was an exhaust rattle, so I took it to an exhaust place who tightened everything up and confirmed that they thought it was Pinking. For those who are new to here, my car was rolling road tuned by Sanspeed who superchipped it to the nth degree while it was running on a diet of Optimax and with a K&N filter.

Now I'd taken to filling my car up at a local super market with 95 ron unleaded, so yesterday I went to Tescos and added 40 litres of 99 ron superunleaded. The pinking was 90% improved straight away but there is still a slight rattle.

My question to the mechanically minded is this:

1. Will the pinking stop when I next completely fill up on 99 ron or do I need to return the car to the state of tune is was when superchipped i.e do I need a K&N again -does the air input effect pinking.

2. What is pinking?

3. What damage will I have done driving around with the engine pinking when under load.

Thanks in advance.

 

[kikkthecat]

I'm sure there are others who know more than me and may contradict me but in answer to your questions from what I understand about pinking from my dim and distant past are,

1. The 99 ron should stop it altogether. Wether the air filter will make a difference I dont know but the fuel to air ratio will.

2. Pinking is pre detonation. I.E. the fuel is exploding under pressure before the spark ignites it. This is nearly always caused by using a lower rated fuel than you should be. A lower ron rated fuel will self ignite at lower pressures.

3. Because the fuel is exploding before it should, engine damage can quite easily result. What's happening is the fuel explodes, trying to drive the piston downward, while the crankshaft is still driving the piston upwards on the compression stroke.

I would have thought a modern engine management system would have detected it happening and adjusted the timing to compensate.

Wether the chipping and tuning has anything to do with that not happening I couldn't even hazard a guess, way out of my depth.

 

[R2D2]

Thanks Ray. Doesnt sound good I wonder if any of the others have any further knowledge?

 

[PJH]

2. Pinking is pre detonation. I.E. the fuel is exploding under pressure before the spark ignites it.

It's trying to be a DIESEL
I think a BIG tuning mod would require higher octane fuel all the time.

 

[R2D2]

.........so I will obviously go back to 99 ron all the time, but is going back to a K&N necessary and what damage have I done and how will I know?

 

[se97mlm]

Yes, there's very little tuning you can do on a normally aspirated petrol engine, save optimise it for a higher octane fuel or connvince it you are half way up a mountain or that it's permanently -5degc!

You should always run it on super unleaded otherwise the pinking will result. It happens if the timing is too advanced - one way to get more power i think.

 

[Thmsshaun]

You should always run it on super unleaded otherwise the pinking will result. It happens if the timing is too advanced - one way to get more power i think.

That is one of things that the chipping / re mapping does.

 

[R2D2]

I've been on to Sanspeed who tuned the car. They said you must use the higher ron fuels because thats what it has been tuned to run on. They were surprised I had such noticeable pinking on 95 ron fuel but that maybe I had bought a duff batch of fuel.

Using the K and N was desirable but not essential to the smooth running of the engine.

They doubt I'd do much damage in normal driving as problems only occur when the engine gets very hot.

Back to 99 ron fuel then. Sym if you read this, have you still got something in your garage!

 

[Robby]

Worth checking the plugs too, if the gap has opened up it may slightly affect the timing slightly.

If it was a 2 stroke bike I'd be fitting a colder plug - higher number is colder, so if it runs an 8 now I'd go up to a 9. Could try that.

 

[R2D2]

My plugs were upgraded to bosch ones at the time but I dont know what ones they are by number etc. Maybe have to find out.

 

[Will]

Greg,

Taking a quick alternative view on this - are you sure you haven't got the dreaded cat-rattle that plagues many W202s, especially 4-cylinder ones

Just a thought that ties in with your original exhaust thoughts.

My old C200 started doing this, mainly under acceleration from lowish speeds - you'd hear it more with the window open!

Worth considering/ruling out if the 99RON doesn't cure it

Will

 

[sym]

Back to 99 ron fuel then. Sym if you read this, have you still got something in your garage!

Sure have .... but isn't yours designed to last a lifetime anyway? ... doesn't it just need re-oiling ? You are welcome to it if needed - just drop me a PM.

S.

 

[R2D2]

Greg,

Taking a quick alternative view on this - are you sure you haven't got the dreaded cat-rattle that plagues many W202s, especially 4-cylinder ones

Just a thought that ties in with your original exhaust thoughts.

My old C200 started doing this, mainly under acceleration from lowish speeds - you'd hear it more with the window open!

Worth considering/ruling out if the 99RON doesn't cure it

Will

I asked steve about that and he said they last til 120k.............lets hope they do!

 

[R2D2]

Sure have .... but isn't yours designed to last a lifetime anyway? ... doesn't it just need re-oiling ? You are welcome to it if needed - just drop me a PM.

S.

You have mail!

 

[Will]

I asked steve about that and he said they last til 120k.............lets hope they do!

My old one rattled at 90K!

Might still be worth checking - what's the mileage on your C200 now?

Cheers

Will

 

[R2D2]

My old one rattled at 90K!

Might still be worth checking - what's the mileage on your C200 now?

Cheers

Will

LOL 87,500!!!

 

[Will]

LOL 87,500!!!

Worth a check then?!?

Probably not this, but I'd check it...

Will

 

[R2D2]

what happens when your cat goes. I presume the rattle gets worse and worse?

 

[Will]

Pretty much - I think once the rattle starts it's downhill from there

Other dilemma is that new aftermarket ones are normally rubbish, proper MB replacements are £££s, and S/H ones can be dubious (shock/impact doesn't help apparantly).

There is also a risk (albeit probably quite small at this stage) that particles of the cat can find their way back into the engine causing damage

While I 'ummed' and 'arred' for a few months about my best course of action, I ended up buying another car anyway. A friend of mine bought it (knowing all faults and imperfections that I could think of!), and it's still going strong - he's not changed it 'yet'

Good Luck

Will

 

[pluggers]

what happens when your cat goes. I presume the rattle gets worse and worse?

If a big enough chunk breaks off it can get stuck in the exhaust pipe and block it and it will feel like your driving a citreon 2cv 0-60 in 30+ seconds its what happened to me 2 years ago,Its annoying