Knocking sound after car sat for a few months

[Greg Futral]

Good Afternoon,

I have a 2002 Mustang GT. It developed a miss, and I did not get around to fixing it. The trickle charger says the battery is charged. I tried to start it, and it will not turn over. What is disturbing to me is that there is a loud sound (in the garage with the hood up) that sounds like a knocking or rapping sound. Any ideas? Thank you!

Greg Futral
Joppa, MD

 

[Miltoid]

So you got it running and it has a knock?
Try to turn the engine over by hand.
Does it turn? If so turn on the headlights and try to crank the engine. Do the lights dim down or go off? If so you may have a dirty terminal or a bad battery.

 

[Greg Futral]

I did not get it running. The noise scared me. Thank you!

 

[07GtS197]

So It doesn’t turn over. Just a single click/thud when you turn the key? If that’s the case the starter solenoid is probably frozen. Give it a technical tap with a rubber mallet to free it up and it should spin again. The starter will need to be replaced.

 

[Greg Futral]

No it was a number of loud noises that reminded me of a old Fiat 124 that needed a new engine. I can't remember how many noises, but perhaps a half dozen or more all withing what seemed to be a second or two. I googled what does a rod knock sound like, and it kind of sounds like this.https://www.google.com/search?q=what+does+rod+knock+sound+like&oq=&gs_lcrp=EgZjaHJvbWUqCQgAEEUYOxjCAzIJCAAQRRg7GMIDMgkIARBFGDsYwgMyEQgCEAAYAxhCGI8BGLQCGOoCMg8IAxAuGAMYjwEYtAIY6gIyEQgEEAAYAxhCGI8BGLQCGOoCMhEIBRAAGAMYQhiPu!ARi0AhjqAjIPCAYQLhgDGI8BGLQCGOoCMhEIBxAAGAMYQhiPARi0AhjqAtIBCTEzODFqMGoxNagCCLACAQ&sourceid=chrome&ie=UTF-8#fpstate=ive&vld=cid:4d2142be,vid:wmtBqNnnvrs,st:0 There was not this noise when the car started misfiring a few months ago. The oil is full. Thank you!

 

[RAU03MACH]

It's going to sound crazy but rotate the engine backwards counterclockwise a full turn then try starting it it has a slight hang in the engine somewhere
My 5.4 did it to me twice last year winter start up
And it was sitting for 3 years

 

[RAU03MACH]

Make sure you are at 13 or better volts

 

[Greg Futral]

Thank you. I don't know enough about rotating an engine backwards. I almost flunked wood shop. I had 12.8 volts on the battery when I tried starting it. Thanks.

 

[RAU03MACH]

find a socket that fits the harmonic balancer bolt 1/2 breaker bar and socket deep wall
turn balancer counter clockwise

 

[Greg Futral]

Thank you!

 

[GTamas]

How you describe it I would guess it's your battery making problems. Rapid clicking noise without the engine turning would be that.
Something like this, but every car could sound a bit different.

You could also make a video of the sound, it would help us help you.

 

[Greg Futral]

Thank you so much. It kinda sounds like the machine gun the guy with the British accent speaks of. So maybe just hook up some jumper cables from the SHO.

 

[96blak54]

I wouldnt rotate a modular engine backwards. If tension has been lost on the timing chains, a slipped tooth can occur on the crank sprocket ultimately killing the cam timing. And that leads me to say a loud knock noise could be the tensioners not in full function and the chain is slapping around. After nearly 1 hour of run time and multiple oil changes(not sure the multiple oil changes helped any)the knock subsided when my friends mustang had sat for over a year not running. Hopefully this is your scenario

 

[Greg Futral]

Thank you!

 

[cobrajeff96]

Jump another car's battery in parallel with the Stang's battery and retry starting it.

 

[Greg Futral]

I am going to do that. Thank you!