pinking issue

[Simpson]

Well traced my timing issue down to there being 3 bolts missing from the left side of the inlet manifold and the others had come lose, no wonder it has run crap for weeks. Replaced those and the engine still pinks under load at slow pace. The timing was checked before the bolts were found missing.

Would the timing need to be done again now they are replaced. Blue sensor seems to advance like it should alos.  Thanks

[rossbarry1]

what car?

[Simpson]

sorry mk gti 8v digi

[rossbarry1]

recheck ignition timing. follow rubjohnnys guide. worked for me.

[danny_p]

check the knock sensor or just replace it

[Simpson]

cheers will do 

[scarr89]

check the knock sensor or just replace it

Is that actually a genuine sensor? A knock sensor? What the F does it measure, if something is banging against it? Also what is pinking? 

[dan2252]

knock sensor basicaly.. sensors for a knock from the engine, and if it detects a knock it puts the timming back,

[danny_p]

pinking is also know as spark knock,   knock sensor measures knock or pinking

to be more technical they are a peizo electric microphone that is tuned to sensitive to vibrations in the block at around 5.5 khz   ( the frequency of the sound you hear thats called pinking )

[Kamshaft]

Pinking is detonation, which means that fuel is spontaneously igniting in the chamber. 
Normally the air fuel mixture should ignite at the spark from the plug and the flame should spread evenly through the chamber.  When you are getting pinking it's because the fuel is igniting at the edges of the chamber  before the flamehas spread to that part of the chamber.  Its normally caused by hot spots in the chamber. Detonation occurs after the spark and engines can handle a certain amount of detonation.  It is normally sensed by the knock sensor and the ECU will retard the ignition timing to eliminate it.

It is often confused with pre ignition which is when the fuel ignites in the chamber before the spark and is much more damaging to engines, normally even one incident of pre ignition will mean costly engine repairs.