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Discussion Starter #1
I just got a 93 7.3 idi non turbo and it sounds weird out of the exhaust like a thump, is that normal?
 

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Hard to say by staring at a 'puter screen. What you're hearing could be integrity, or lack there of in the exhaust system. It could also be leaking valves. You have to decide, valves would be a hissing, more than thump. A loud heavy thump might be engine troubles, and not in the exhaust at all. If you can send a video, maybe someone can tell you what it is.
 

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Discussion Starter #4
 

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That sounds a little like an engine knock. With it running, crack your injector lines at the injectors one at a time see if the noise goes away. If it does, that would be the cylinder with the problem.
 

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Discussion Starter #7
I have cracked the lines and it stays, the motor sounds great I’m wondering if it’s the exhaust the guy I bought it from has in it
 

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Does it get louder, or quiet down with load/RPM? Does it go away completely? What does it sound like under the hood? Same, or does it get quiet?
 

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Discussion Starter #9
Under the hood sounds fine no knock and when you’re driving or rev the engine it goes away it only sounds like that at idle
 

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From outside the truck at the tailpipe, does the sound stay at higher RPM? Does it go away completely, or does it just get faster?
 

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It is probably just something loose in the exhaust system. There is the possibility of maybe an exhaust valve starting to leak, but it would have to get worse in order to hear it well. It will also start to miss if that is the case.
 

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Discussion Starter #13
I’ve never really been around the idi’s that much I just didn’t think that sounded normal
 

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Sometimes you scratch your head and wonder. Wait awhile, it'll either get louder (something wrong), stay the same, or just fade into the background. Any way it goes, It doesn't seem to be any trouble unless you start to hear it under the hood, or it stays through the RPM range.
 

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Discussion Starter #15
I decided to straight pipe the truck and get rid of the exhaust they had and now it sounds better but it’s still got a weird sound it almost sounds like a Harley sitting there idling
 

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Then I would suggest that you run a compression check, to see if maybe you have one or more burned exhaust valves. That recording didn't sound like it, but things sound different in recordings than they do in real life. The fact that the engine isn't missing yet, only might mean that it isn't bad enough yet to cause the miss, and loss of power. Get it now, it might just be a head rebuild, wait until later, you might be rebuilding the whole engine.
 
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