LLY: duramax knocking.. [Archive] - Duramax Diesels Forum

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kman2468
05-10-2010, 06:00 AM
ok here is a video of it. this is while sitting still
http://www.youtube.com/watch?v=1p4E5DEZfJk
it goes up with the RPM's and i dont know what it can be? i hope you can hear it in the video. I dont know if it is just the typical knock, but i would think it wouldnt be that audible while driving. any help would be appreciated please
did the balance rates test

here are my injector balance rates
i saw in park one reached over 4.0 so is that bad??
i know above 4.0 is bad but its not that much out?
here was in park
http://i196.photobucket.com/albums/aa307/kman4564_2007/balancerates.jpg

here was in drive
http://i196.photobucket.com/albums/aa307/kman4564_2007/balancerates2.jpg
also this was on my 20hp econ tune does it ahve to be stock??

dmaxfireman
05-10-2010, 07:35 AM
check your balance rates. tough to get actual sound through the video but if it is extremely loud it may be a bad injector connection, if your balance rate is off on just one cylinder then lookup to 'icepick fix'

kman2468
05-10-2010, 09:06 AM
It's not extremly loud like when my one injector went bad last time but it is loud

kman2468
05-10-2010, 12:20 PM
added my balance rates up there

kman2468
05-10-2010, 09:14 PM
anyone else got any opinions

kman2468
05-11-2010, 08:59 AM
is it possible to bend a rod on like a 120hp or less tune??
what are symptoms of bent rod

Kat
05-11-2010, 01:59 PM
Do you have white smoke at idle? If you have a bent rod most likely you would have white smoke.

02bigstrokin
05-11-2010, 02:00 PM
is it possible to bend a rod on like a 120hp or less tune??
what are symptoms of bent rod

if your worried about a rod, do a compression test. smoking white at idle can be a sign of a bent rod. a 120 tune shouldnt do it, but nowadays you never know whats going to happen and for what reason.

kman2468
05-11-2010, 02:11 PM
no no smoke at idle...im just throwing thigns out.. i cant figure out why its knocking..its knocking super loud like when an injector doesnt work anymore..but it is noticeable

S Phinney
05-11-2010, 07:06 PM
I would do a compression test. Maybe that will give you some ideas into the problem.

kman2468
05-11-2010, 07:25 PM
how do i do a compression test? would my upper radiator hose be hard if i bent a rod? i dont know how i could but who knows now a days

kman2468
05-11-2010, 07:27 PM
oh BTW i noticed more of a diesel smell out of my exhaust not REAL strong. but it is stronger than it was

GeorgiaDuramax
05-11-2010, 08:59 PM
You find anything out kyle?

kman2468
05-11-2010, 09:06 PM
nope...but there is another guy on the DF that is having same problem i am but on the passenger side

JMK777
05-11-2010, 09:13 PM
any codes? what dose the oil look like? any fuel in it? could be a injector

whitetrash21
05-11-2010, 09:19 PM
compression test is done by pulling the glow plugs out one by one and testing cylinder pressure through there, It'll tell you real quick if its bent rods or not.

kman2468
05-11-2010, 09:27 PM
nope no codes..and now im worried about it being a bent rod..

kman2468
05-12-2010, 09:48 AM
well im going to eliminate a bent rod because there is no white smoke...i hope i can eliminate it

DirtySouth85
05-12-2010, 11:32 AM
I think the only reason your radiator hose would be hard would be if there was a blown headgasket.... That's not from experience.... only hearsay. Good luck bud!

Cougar281
05-12-2010, 11:54 AM
compression test is done by pulling the glow plugs out one by one and testing cylinder pressure through there, It'll tell you real quick if its bent rods or not.

No sir, you must pull ALL glow plugs in order to get an accurate compression test.

kman2468
05-12-2010, 11:57 AM
the radiator hose isnt hard lol. but i was wondering if i bent a rod. which i dont think and am hoping i did not.

whitetrash21
05-12-2010, 12:05 PM
No sir, you must pull ALL glow plugs in order to get an accurate compression test.



Any particular reason why? I che'ked my 03 that way and all the cylinders were within 10% of each other.....which isnt to say that all 8 were bent but....

Why would doing it one at a time not be accurate? Is it easier to turn over with all 8 plugs out and only one cylinder making pressure?

DIESELMAFIAPER.LB7
05-12-2010, 12:23 PM
Use efi live an turn Injectors off one by one an see if it helps or makes the noise worse an I can't hear the noise but maybe stuck valve

Cougar281
05-12-2010, 12:53 PM
Any particular reason why? I che'ked my 03 that way and all the cylinders were within 10% of each other.....which isnt to say that all 8 were bent but....

Why would doing it one at a time not be accurate? Is it easier to turn over with all 8 plugs out and only one cylinder making pressure?

I'm not exactly sure, but I think it has to do with eliminating as many variables as possible, such as if you have a bent rod or two, fried rings.... Anything that will affect the compression of a cylinder, when the affected cylinder(s) come up on the compression stroke, they'll have less resistance at the top of the stroke than the other cylinders, so there will be variations in the crack speed that could throw off readings for other cylinders. When you only have the one with the gauge "plugged", the other 7 cylinders will have no impact on reading the current cylinder regardless of their condition.

It could also have to do with the fact that no plugs in the motor will result in far less effort to turn it over, thus reducing battery drain.

The GM "How To" specifically states to remove all glow plugs, as does pretty much everything you can find on the 'net through a Google search....

Now, will it be "close enough" to give you an idea if you rmeove one at a time? Possibly.

whitetrash21
05-12-2010, 01:16 PM
Ah. Ok. That makes sense. Never thought about anything else affecting cyl pressure when i did mine. Thanks, have to remember that.

Kat
05-12-2010, 02:45 PM
Here is something Pat wrote

http://www.duramaxdiesels.com/forum/showthread.php?t=2091&highlight=compression+test

kman2468
05-12-2010, 03:58 PM
so does anyone still think its possible a rod could be bent if there is no smoke?

whitetrash21
05-12-2010, 05:01 PM
Very minor ....maybe. When a rod bends, your compressions ratio drops, and depending on how much bend it has is what varies the amount of CR drop. The lower you drop it, the less the fuel will burn completely, thus the white smoke.

Do a compression test, that will tell you a lot right there.

kman2468
05-12-2010, 05:21 PM
oh mannnnnnnnn. hoping it is not that... ok thanks everyone for all your help BTW!!

kman2468
05-14-2010, 05:52 AM
well i think it is slowly getting worse. i hear louder knocking everyday, no smoke yet.

kman2468
05-14-2010, 12:44 PM
got another vid...crappy sound again let me know if you can hear anything i cant
http://www.youtube.com/watch?v=CEZJdj1eu0M

Triple L
05-14-2010, 05:37 PM
my trucks sounded like that since day 1, or maby im not hearing what your hearing...

kman2468
05-14-2010, 07:04 PM
maybe i dontk now what im talking about and its normal? idk everyone knows more about these trucks than i do

wilsonck
06-27-2010, 09:04 PM
Did you ever figure this out? Did you ever do the compression test?

kman2468
06-28-2010, 08:51 AM
nope still does it. and no i didnt do a compression test. im just waiting for something to go. i hope its just injector that is waiting to go at any point

kman2468
06-28-2010, 10:48 AM
i ran balance rates again..
here is in park
http://i196.photobucket.com/albums/aa307/kman4564_2007/parkbalance.jpg
here is in drive with brake held
http://i196.photobucket.com/albums/aa307/kman4564_2007/drivebalance.jpg

duratothemax
06-28-2010, 02:08 PM
I highly highly highly doubt you have a bent rod. If you did you would see balance rates out way more than that. Still try to do a compression test though.

kman2468
06-28-2010, 02:28 PM
Can an fpr make it knock? Ik u told me on df u doubt it is a rod. And i would think if it was a rod it woulda fully bent or broke by now.

JMK777
06-28-2010, 03:59 PM
Do you have a lift pump? if so turn it off at idle and see if it go,s away. log your rail at idle if you get a chance

kman2468
06-28-2010, 04:18 PM
Nope no lift pump. i was thinking about getting one

JMK777
06-28-2010, 04:25 PM
Can an fpr make it knock? Ik u told me on df u doubt it is a rod. And i would think if it was a rod it woulda fully bent or broke by now.

fpr can make it knock as well as lop.
I would log rail next if i where you. how dose it sound while cruising, say 45mph ?

kman2468
06-28-2010, 05:17 PM
i can hear a slight knock while cruising it is mostly with throttle, it can be light, or heavy

kman2468
06-28-2010, 05:18 PM
i logged actually vs rail pressure

05stocklly
06-28-2010, 08:11 PM
I think I had the same problem. But mine felt like it had no balls when trying to accelerate too. I turned the programmer to stock put some ATF in the feul to help clean the fuel system out, run it hard for acouple of weeks and noticed it was gone. I bump the programmer back up and all was good. Still not sure what it was but its gone for now.

kman2468
06-28-2010, 08:14 PM
well ive put additives in it and it seemed like it helped, and then when that stuff was gone, it was back. or atleast what i could tell..idk

05stocklly
06-28-2010, 08:25 PM
The only why I can explaine the knock I had was it accually sounded like a diesel when I stepped on even just a little, not the nice Duramax sound.

I was told that it was probably some build up from the higher tune, and not really using the power, like towing something works the motor harder than just quick take offs and then cruising. Just don't go crazy with the ATF I was told just a couple ounces a fill up will do.

kman2468
06-28-2010, 08:34 PM
well thats what im saying it isnt the normal duramax noise. could be normal diesel? but egr wouldnt cause this would it? cause i dont have mine blocked

05stocklly
06-29-2010, 04:04 PM
I don't have my egr blocked either. I'm not saying it will work but it might be worth a shot. Maybe someone else will chime in about this.

kman2468
08-31-2010, 07:40 PM
well..its getting worse..and it sounds like something is about to give :(
i dont have money for what i think it is. cause of course im thinking of the worst that it could be a bent rod..

Akdiesel
08-31-2010, 08:05 PM
Why don't you follow the advice that was given and do a compression test?:thumb:

kman2468
09-01-2010, 04:43 AM
because i dont trust myself enough to do all that yet..

Akdiesel
09-01-2010, 05:37 AM
Understandable but if it was a bent rod wouldn't you like to know...i mean closing your eyes and pretending it isn't there won't make it go away

duratothemax
09-01-2010, 06:33 AM
you need to do a compression test. No one can help you or give you any more advice until you do. I highly doubt its a bent rod.

ripmf666
09-01-2010, 09:57 AM
If it's a bent rod won't be long til he can see it up close. I would atleast try and save your block and crank and what ever other part you could. It's better then looking for a whole new motor to build or replace with.

Redbowties88
09-01-2010, 10:00 AM
x2 kyle get a compression test and for giggles run your balance rates again and use the dvt tool to turn off injectors..

kman2468
09-01-2010, 12:12 PM
is it possible to like drive a little with one cylinder turned off? because that is only way i can tell its knocking is in the higher RPM's like near 1500. and only in drive. or is it bad? and my balance rates were all in check. but my number two was 3.6. anyone know how much dealership charges for compression test? i work two jobs and dont have time to do it

Redbowties88
09-01-2010, 12:57 PM
you can drive with an injector turned off. i drove like 10 miles with only 4 working ;)

kman2468
09-01-2010, 01:15 PM
i can? well ok thats good um so if it stops knocking then that will let me know if its injector right? or if its turned off could it still be rod?

SparkZ03DMAX
09-01-2010, 02:08 PM
Dam now ur making me worry about a bent rod.

Akdiesel
09-01-2010, 02:24 PM
Running the power levels you guys are at I HIGHLY doubt you bent a rod. I'm running a pony or two more and have yet to have any worries...

duratothemax
09-01-2010, 03:56 PM
i can? well ok thats good um so if it stops knocking then that will let me know if its injector right? or if its turned off could it still be rod?

Turning off an injector and listening for the knock to go away doesnt tell you if a rod is bent or not. All it tells you is if the rod BEARING is shot.

JMO.

Ben

01LB7
09-01-2010, 04:32 PM
maybe i'm way way off in left field, but what does your oil preassure guage do at idle, does it tick really bad and dance between 0 to 60lbs until you put the fuel to it? saw one do that before and it made a wierd ticking sound, then broke

kman2468
09-01-2010, 06:18 PM
Turning off an injector and listening for the knock to go away doesnt tell you if a rod is bent or not. All it tells you is if the rod BEARING is shot.

JMO.

Ben
alright. i was just curious. i have no clue about these trucks like everyone does on here
maybe i'm way way off in left field, but what does your oil preassure guage do at idle, does it tick really bad and dance between 0 to 60lbs until you put the fuel to it? saw one do that before and it made a wierd ticking sound, then broke

oil PSI almost stays constant maybe like up down 1-2 psi



also this is for everyone.. does overheating the truck weaken anything? because like 5 years ago we overheated the engine and trans. i didnt have egt gauge. but the ECT was HOT. and we let it cool down. no headgasket was blown or anything. just had everything changed. but could that of weakend it? im just trying to throw things out there that i think coulda caused it. cause i dont have time to do any compression test. and dont have a car to drop it off at dealership