Knock Knock, Sound Just At Starting Options

[windforfun]

Does your 1.7 make a knocking sound just at starting? It happens just before the engine starts to run. Mine has always done this & I can't find anything loose or anything hitting anything within the engine bay. Normal? Thanks.

(IMG:style_emoticons/default/dry.gif) (IMG:style_emoticons/default/dry.gif) (IMG:style_emoticons/default/dry.gif)

[Superhawk996]

Video is going to be your best bet to get some real help rather than speculation.

There are so many things it could be.

I’ll give you a speculation:

Could it be timing? If your static timing is just a little bit too advanced? As engine is cranking slowly - sometimes you can get an ignition event too early in the compression stroke. It will sound somewhat like a rod knock. But then the engine catches on subsequent cylinders, rpm’s increase and then the advance is more appropriate to engine speed and the knock sound disappears.

When static timing is way too far advanced, you will get an outright cranking stoppage - stall of the engine because the ignition event happens so far before TDC it just stops the upward piston travel in its tracks. Usually with a clunk / knock / stall sound. This clearly isn’t happening in your case but there is a continuum between seamless starting and this worst case no-start & clunk/knock scenario.

Problem is we don’t know if this is what is happening on your car or if I’m just pulling this out of my (IMG:style_emoticons/default/bootyshake.gif)

Having someone crank - start while probing the engine with a mechanics stethoscope would go a long way toward narrowing down what you’re hearing or where it’s coming from.