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5.3 issues

ak diesel driver

ak diesel driver

6.5 driver
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So went to start the burb this evening and it made a horrible racket. Pulled the belt to see if it was an accessory and it wasn't. Sounds like serious detonation or mechanical problems any ideas?
 
Codes?
Oil condition? Engine and transmission...
Coolant level and condition?

Running out of fuel (aka any fuel problem like failing pump) will cause the engine to knock with low fuel pressure at idle.

You know these short skirt pistons with sloppy GM assembly line tolerances knock while cold? :D GM had to buy a lot of the early 5.3's (and other engines/vehicles) back over it.
 
I had quite a bit of cold piston slap with the '02 5.3 but not the '07. Up to '03 it was almost a given at some point. When was the last time you ran the piss out of it with a healthy dose of injector cleaner in the tank?
 
Is the engine starting? Get a look at the flexplate.

Can you can crawl under and chase it down stethoscope style?

I've seen catalytic converters come apart and at first everyone would swear it was a crankshaft trying to turn sideways.

Video killed the radio star, but helped on the forum...
 
Sorta like a 'chirpy tick'? Maybe time for a cam and lifters. Seized roller and/or collapsed lifter plunger. Some suffer from oil pickup problems- sucking air into oil pump.
 
no codes and it does start instantly and knocks/clatters really bad. It was running fine when I drove it Sunday parked it and it started making noises instantly when it was started next. I am leaning towards it being a detonation/timing issue. just odd that it happened so suddenly
 
Pull the ECM fuse so it will crank and not start. See if the noise is there while spinning (cranking on the starter). You could also hand turn the engine.
 
Wow that's noisy. Can rule out cam and lifters pretty sure.

Engine sounds like it is not smooth at all, like 5 cylinders firing or something.
 
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