m0dnar

I was hoping the more knowledgeable members can help me out with something. This car is my first V8 so I'm not sure if the engine noise I'm hearing is normal or if there's something to be concerned with.


Can someone listen to the video and see if the ticking/clicking noise is normal? Car is a C7 3LT Z51 if that matters.

djyankees31

It sounds normal to me.

NSC5

The ticking/clicking is the high pressure fuel pump and that is NORMAL for this (and other) direct injected engines. The LT1 and LT4, like most current GM engines, use high pressure direct injection and this requires a much higher fuel rail pressure than previous forms of port injection. The high pressure pump is driven by its own lobe on the camshaft and this creates a clicking/ticking noise that propagates through the common fuel rails that feed the injectors but it will be loudest near the rear drivers side of the engine which is the location of the pump.

It will be more noticeable at idle and the sound will change some with temperature. With a direct injected engine you will also notice it cranks slightly longer before it fires and this is because the fuel pump must build up the commanded rail pressure before the injectors are operated. It will also take longer in colder weather due to slower cranking speed; the engine is making the same number of revolutions to build the pressure but because of slower cranking speed (increased oil viscosity and reduced battery output from the cold) the time to start will be slightly longer.

Direct injection is one of the key strategies that allows greatly increased engine output while also meeting strict emissions standards and the ticking/clicking of its high pressure fuel system is a pretty minor price to pay. My first direct injected gas engine was a 3.6L in my 2008 Cadillac CTS and even though Cadillac added a lot of sound deadening it was still audible. Now direct injected engines have become far more common and manufacturers are far less concerned about hiding the fuel system noise.

walleyejack

sounds like it needs a bigger cam to me

m0dnar

Thanks for the thorough response describing exactly what it is I'm hearing. It's good to know there's nothing under the hood I need to get taken care of under warranty. My last GM car was a 2013 Camaro 1LS that I built to 460 rwhp so I don't even remember what that car sounded like stock.

madrob2020

m0dnar

I plan on driving it for a few years stock and then building a 700 rwhp monster.

383vett

Sounds normal

lakemg

Also needs headers...