Forum Home / Ask the Experts! / K Series 16V MPI "Pinking"

12/11/2007 21:52:11
Graham 180
Hi, does anyone know what the most likely cause of pinking is in the Rover K series 16V MPI engine (Metro GTI) ? I have just bought the car for use not only for occasional trackdays (normally use my MGZS 180) but to compete in MSA sprint events 1400cc and below class. The car starts and runs fine but under load throughout the rev range it will pink. Any suggestions what to check first ?
15/11/2007 07:08:34
Tim Guy
Spark timing is controlled by the ECU according to a number of inputs, predominantly crank angle sensor and inlet manifold pressure. Its not really adjustable unless a previous owner has had a remap of some kind. Try running on a higher octane fuel. The other causes of pre-ignition are hot spots in the head from carbon build up or using spark plugs of the wrong grade (too hot)
15/11/2007 20:43:15
Rob Bell
Going back to basics, pinking means that the engine is running lean under load. In this case, it might mean a leaking inlet manifold, leaning out the mixture as it enters the cylinder head. Or it might mean that the amount of fuel being injected into the combustion ports is inadequate. The latter could be due to faulty injectors (might simply be dirty - could respond to injector cleaner), or it might mean the fuel rail is not adequately pressurised - be that due to a failing old fuel pump, or the fuel pressure return valve not working to spec. Balrog makes some good suggestions - so plenty to be looking at Graham - do let us know what you find!
16/11/2007 18:54:33
Graham 180
Thanks for the suggestions, I'll have a chance to get my hands dirty under the bonnet on Sunday. I'll let you know what I find. Thanks again
16/12/2007 18:59:12
Graham 180
I've been finally able to find out what is going on with my pinkin Metro GTI. It wasn't pinkin at all (and I feel really stupid !). The exhaust is blowing under load at the joint in front of the cat. Its makes a sound (which I had mistaken for pinkin) under load. It being forced out at such high pressure it just does not sound like an exhaust leak. Thanks for the suggestions as I did find a hole in one of the inlet manifold pipes. See at a track day in the near future ! Thanks again Graham 180
16/12/2007 21:33:20
Glad you got it sorted Graham. Exhaust issues can be so varied and misleading can't they, but thankfully relatively easy to fix once you've found them!
16/12/2007 23:46:42
Graham, While your removing the front exhaust section to reseal the joint properly I suggest you check the catalyst has not melted on its front face. It sounds suspicious that there is so much pressure in the exhaust. Dave
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