Power Fc Knock Levels On Start Up

[viking]

got my car tuned and noticed the knock levels on the hand

controller reaches 106 on start up.

surely this is not normal????? correct me if im wrong

any comments?

[MattSR]

The engine is cold and all the oil has drained back to the sump. my guess is that the sound of hydraulic lifters with no oil (perfectly normal at start) is falsely triggering the PFC knock sensor.

Cheers,

Matt

[m&m]

I thought GTR was solid lifters.

[Robo's]

106 seems a bit high on start up but mine always pushes 40 on start up. So i reset as soon as i start it

[MattSR]

Ahh yeah you are right - I though he had an RB25 for some reason..

viking, do you have any other mods to your motor? forged pistons or anything else? I dont really think its anything to worry about as the engine isnt undr load at idle/startup so theres not going to be any damage due to detonation. Still interesting to figure it out tho

[siksII]

when i had my stock fuel pump startup knock was never above about 5 or 10

i put in a bosch pump and now sometimes it will be around 40-50

i believe the bosch pump does not have a valve to keep the lines pressurised when the pump is not on, so after it primes if u wait a bit it may be a bit starved of fuel on startup causing the knock.

i have tried a few things and noticed if i prime a couple of times and start it right away it starts perfect, however if i prime once, leave it a while then try and start it may not start at all.