What is this Knock? (with video)

[Chaseman]

Its had it for years , I've tried pulling plug wires but doesn't change the noise. I'm thinking of pulling the fuel pump and see if it quits.
http://www.youtube.com/watch?v=2pyM9s2FeYM[/video]

[papabug71]

I have never heard a fuel pump knock when you throttle up, only at idle. They tend to be louder at idle.

When you go up in RPM's it almost sounds like bottom end rod knock.

Get a super long screwdriver & stick it to the fuel pump & listen. If its the pump, the knocking will be super loud!

[ToughOldFord]

I almost thought rod knock, but after 'years' of driving you'd think it would have spun the bearing by now??
For Chaseman's sake hopefully it's not.

[fireguywtc]

I had the same knock on my fuel pump after I rebuilt my motor years ago. The pump didn't knock priort to the rebuild but when I put it back on it knocked. How did you plan on pulling the fuel pump to see if it quits? just curious.

[Chaseman]

Thanks for the input , I just can't imagine a rod knock lasting that long and still be alive. As for my fuel pump plan is too take it out , block the hole and then run off a gravity feed for gas. Also I'll try the long screw driver idea.

[sideoilerfe]

Thanks for the input , I just can't imagine a rod knock lasting that long and still be alive. As for my fuel pump plan is too take it out , block the hole and then run off a gravity feed for gas. Also I'll try the long screw driver idea.

You will need a pump to drive your truck. To check the knock, Remove it, start it and see if it still knocks. It'll run for about a minute before it runs out of gas. If it stops then you have your answer.

[70_F100]

That, my friend, sounds suspiciously like a loose rod.

The bearing can be worn, but not scored.

I'd pull the pan and check the bearing if I were you.

If that's not it, check for a cracked skirt on a piston. Pulling the plug wire won't always detect that.

I know...

[Chaseman]

Okay I'll remove the pan if it isn't the fuel pump.... Also a cracked skirt on piston? How bad is that if that's the case?

Thanks
Chaseman

[sideoilerfe]

Okay I'll remove the pan if it isn't the fuel pump.... Also a cracked skirt on piston? How bad is that if that's the case?

Thanks
Chaseman

The engine will have to come out and then come apart to replace the pistons. If you go that far, you're better off rebuilding the whole engine properly.

[1971ford]

ahh i was going to say it sounds exactly like my knock, (99% sure it is fuel pump) until you revved it! Definately sounds like something is fudged up inside there

[fordman]

sounds very similar to a rod to me. i have never heard a fuel pump knock either.

[knightfire83]

1 additional vote for a connecting rod.

[DuckRyder]

It sounds like a connecting rod to me...

[hazelnut]

i think its a rist pin,ive heard two motors with a bad rist pin and they sounded like your knock,if you pull your pan off pull your spark plugs to,then you can turn your motor so the pistons come to the bottom of each bore and see if the rist pin feels lose.I would use a piece of heater hose to listen for a knock as it would be easyer on your ear.A rist pin can knock for years and not come lose or it could come lose the next time you start your truck.i had a freind 20 years ago that drove a pinto with a 2.3 and he drove for 3 years with a rist pin knock,he bought a motor to replace it but it never come lose and when he sold the car he gave the spare motor with it.

[george worley]

I had a 289 once that had a knock like that and it was a connecting rod.