Well, I will tell you guys this......You are definitly scaring me!!!! My '00 L has 8100 miles on it and it doesn't make a sound other that your normal dry startup and once the oil gets flowin', it goes away. I have had a chip and MAF kit on the truck for 700 miles now and have noticed nothing. I take that back from my earlier comment on not hearing the "flutter", when it is cold and I give it 1/2 throttle at 3,000RPMs, you do hear a very slight flutter. When the engine warms up, it goes away.

 

Did you try to hear it with the SC belt off?

Mike

 

gforce, my truck has almost 28,000 miles on it now. It still has the Swanson chip in it, and has for about 14,000 mi.

I tried to duplicate your noise. I ran it from 2500 to 4200 in both 1st and 2nd gears. I tried light, moderate and full throttle, and it does not make this noise.

It almost sounds as if there may be an injector problem. Sometimes, if injectors get weak or fail to function properly, it is possible to get what sounds like a rod knock(probably detonation in one cyl. due to lean condition). I'm not sure what the actual cause is, but on some earlier injected GM cars, this happened a lot.

The only noises that I can detect are the cold startup rattling that has been there since I got the truck.

Hope this helps.

Jay

 

DreaminAboutL,
Yep, I know it's not good for it, that's why I hooked it back up. I'm trying everything I can to solve this problem before I take it into the dealership and let them $%@! it up. I REALLY, REALLY, REALLY, REALLY don't want to take in in, but it lookss like I may have to.

gforce,
I just disconnected the wiring harness from the solenoid, the same as many people do at the track. I am more confused than ever now as to the source of the noise.

 

I'm tellin ya!
Try taking the SC belt off and test to see if you hear the noise.
Mine was doin it, reversed the belt and it worked.

 

Be sure when you are trying to reproduce the noise that you back all the way off the throttle at 3K to 4K. Mine only makes the noise when I get off the throttle. That is why at the track I don't get the noise. WOT=No Noise.

 

Thanks to all of you that have responded. I'm just trying to get to the bottom of this and not cause anyone alarm. So far, my engine is still running strong and I don't want to cause it unnecessary damage if possible.

twiztid,

I removed my chip today and sent it for a reburn and the noise went away completely. I can understand what you're saying about the belt, but I think my sound may be different than yours, and if it were a belt, it should do it with/without the chip. When the chip comes back, if it does it again, I'll be sure to pull the belt and do the octane boost like BfB said.

Jay,

Bravo!! Your post is right on point. You duplicated my "locked in gear on a load" test and yours doesn't do it. So it goes to show that not all these engines sound like this. Thanks for the extra effort to answer my post.

My original intent was not to worry anyone, I promise. I was aware before I posted the original message (no SEARCH needed) that many people already have this and have had for many miles. What concerned me was the fact I could drop down in 1st or 2nd on the column and duplicate it between 3k and 4.2k at mild throttle openings. It was a constant "hammering" effect that sounded like one cylinder really going at it. I know for a fact that if this were to occur for a long trip on the interstate towing something, more than likely, something, bad would happen.

Here's the main purpose of my post - I was thinking of getting 4.10 gears, which would definitely make my truck run in the "dangerous range" (3,500 rpms) at about 70 -75 mph with the overdrive off while towing a heavy boat like I plan on getting. I'm almost positive it wouldn't survive based on the way it had been sounding lately and I wanted to see if all trucks did it. Apparently not. Today, without a chip, it sounded really good. I'm almost thinking a sensor of some kind or injector......

Jim

 

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