What are the various causes of Pinking ?

[robincoombe]

Can anyone tell me what the various causes of Pinking are ?
(Pinking, Engine Knock, Pre-detonation -- whatever you want to call it)

I have a 1992 Rev 2 MR2 NA which is pinking a lot when I accellerate. It only does it when I put my foot down, when the engine is under load (either accellerating or going up hill) but it does it quite a lot. As soon as I ease off the pedal it stops.
I don't ever run my car on cheap supermarket petrol, I used to use Shell Optimax but have found that it runs better on BP Ultimate. When I'm using BP Ultimate the affects of Pinking are reduced but it still does it. It's driving me totally mad !


I used to have a 1989 MK1 NA that used to do exactly the same thing.


I know that you can reduce the affects of Pinking by retarding the engine timing but I've checked it and it's exactly where it should be according to the manual, so something else must be wrong.
It has new (relatively ~ less than 6 months old) platinum plugs (which still look clean when I checked them last weekend) and air filter, I only ever use Super never just standard premium petrol. I've tried running Injector cleaner through it -- although I'm sceptical about whether those things really do anything.

Appart from a taking it to a garage and getting it tuned properly does anyone have any thoughts on what I can do to stop it ?



Any suggestions would be Greatly appreciated.

Thanks,
Robin.

[Lauren]

Timing is normally the main cause. Induction temperature can cause detonation as will lack of fuel, but this is more of an issue on a forced induction engine.

That said i've melted a piston due to too weak a mixture before (not Mr2 though).

So if you think about these problems arise from either fueling, ignition or air temp.

Its obviously not air temp, so it comes down to timing which you have already tried and set. Fuel can be the only other cause, ie is it running lean?

What you could do is put it on a rolling road and ask them to check the fueling, it is probalby your best way of simulating under load conditions and i'll be if they are any good the operator will spot the issues pretty quickly. It ought not to cost you that much to at least diagnose the issue.

HTH a little bit.

[crazylegs]

I`d check the timing first as this costs nothing.if its not out then go for other things.i cant help you on how to on a mk2 but it must be simple.bridge the correct terminals and shine your light. cheap and easy!

[Grajey]

Letting Shaf too near your car.

[Jon S]

Letting Shaf too near your car.

[Goldy]

I had a very similar problem in my old rover. I have 3 suggestions if it is not the timing.
1. Check the distributer cap and rotor arm, they may be knackered.
2. Check the spark plug leads, these can become dodgy without much warning.
3. Use a can of 10k Boost on the air intake, your engine might be a bit coked up?

Erm thats all I can sugest. I have muchos problems with my rover. I changed the distributer cap and rotor arm and it improved it a lot. It still pinks a hell of a lot under load. I'm thinking i need new leads / the engine is FUBAR but hell i'm gettin rid of it soon, cos of the MR

[Peter C]

FAO: JJ

Wanna discuss this one again?

[BenF]

Can anyone tell me what the various causes of Pinking are ?
(Pinking, Engine Knock, Pre-detonation -- whatever you want to call it)

I<snip>
Any suggestions would be Greatly appreciated.

Thanks,
Robin.

Robin, this is quite common on the MK2 NAs - its worth checking your timing is at 10 deg BTDC if you haven't already. If its still pinking, it could be due to carbon build up in the cylinder increasing the compression ratio slightly, meaning the car will 'pink' more easily.

A fun, easy cure for this is to take the car to your favorite bit of twisty road, and go for a 20 minute blast and get the engine really hot - lots of throttle, high revs etc - this will burn off any deposits.

Alternatively, book yourself in for a trackday somewhere