My engine sounds like it's eating gravel

[copracr]

I'm having some trouble with a rebuilt motor I just put in and maybe one of you guys can help with this. My motor is making a sound like the flywheel is broken, but it's also doing it during acceleration and it runs rough when the noise happens. The noise cuts in and out. No codes, but fails cyl 8 on the contribution test. I figured I'd swap out #8 injector to see what happened.

I fired it up and it was running pretty rough, as expected. No unusual noises though. I started getting pretty happy and figured I'd drive it around and purge the air. I got about a quarter mile and the noise returned, sporadic at first but now its all the time.

I figure this rules out my flywheel as the problem, but I kinda knew that anyway. It's almost always present at idle, goes away around 1500 rpm, never does it on decel, and comes intermittent on accel. It runs rough and loses power when the noise comes, and it has something to do with #8 cylinder but its not the injector.

I got a bad motor?

[RT]

You mentioned a flywheel but your profile says you have an auto. If the noise sounds like marbles in a can, your torque converter may be bad. Failing #8 is non diagnostic. That's always a weak cylinder as it fires right after its neighbor and therefore has lower fuel and oil pressure than the others.


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[copracr]

Noisy 7.3l - YouTube

Noisy 7.3l - YouTube

Its dark, but noisy

[RT]

I'd take the torque converter bolts loose, slide it back a bit, start it and see if the noise goes away.


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[copracr]

flexplate, sorry.

RT - start it with the nuts off the TC?

[copracr]

Definitely not marbles in a can. More like a hammer bouncing around in the motor.

[RT]

If you can slide it back far enough that the TQ won't spin.


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[91diesel]

You also need to not drive/run it until you figure out what the noise is.

Your torque convertor bolts are tight?

[copracr]

Yea, they're tight. I even pulled the cover off to make sure the flexplate wasn't cracked.

[txemt39]

yes, unbolt the torque converter. that sounds horrible

[txemt39]

was the turbo rebuilt also?

[copracr]

Originally Posted by txemt39

was the turbo rebuilt also?

No, just a visual inspection. Fins looked good, shaft seemed tight.

7.3l aweful noise.mp4 - YouTube


This is first startup this morning, not plugged in. It has a good miss, and around 7 seconds you can hear the noise start. Pay no attention to the tach, it reads high. You can hear it real clear again around 1:20 when the idle comes down after revving it.

While I was out there I ran a buzz test -sounded good. I swapped the under valve cover harness with a spare. Before I start it back up I was wondering how much of a mess would it make to run it with the cover off? I'm thinking of unplugging one injector at a time till the sound goes away. Then I can at least narrow down which cylinder I'm working with.

[jakebeefsteak]

I know that i am not contributing but, that hurt to listen to. Please keep us posted as to your findings.

[91diesel]

Its time to cut your oil filter open. They are cheap, cut it open in some way (big tubing cutter) that wont put metal shavings/dust into the filter (I have used a sharp utility knife once on a smaller one//be careful). Cut a section of paper out, put it folded up in a rag and squeeze it with a vise. Take a pic and post. Who rebuilt the motor?


Did you try sliding the torque convertor back to disconnect the tranny?


Also...your belt looks very loose. Definitely sounds like its coming from engine, but disconnect your belt and see what it does. How long have you run it since you put the motor in?

[floundergigging]

You figure it out yet. Let us know... Thanks