Chevy and GMC Duramax Diesel Forum banner
  • Hey Everyone! Enter your ride HERE to be a part of this months Ride of the Month Challenge!

21 - 25 of 25 Posts

·
Registered
2017 l5p Chevrolet 2500 LT CC
Joined
·
76 Posts
Discussion Starter · #21 ·
I am usually not that lucky. I’m sure it will be back, just a matter of time.

The mechanics really aren’t saying anything for sure, since they can’t replicate it. They are doubting bearing trouble because it went away and didn’t follow the rpms of the truck. Their best guess is an injector blockage. I’m sure I will find out down the road when it comes back.

Thank you for all the replies on this subject. I really appreciate everybody giving me their thoughts.
 

·
Registered
2017 l5p Chevrolet 2500 LT CC
Joined
·
76 Posts
Discussion Starter · #22 ·
Well, my knock is back. It is not nearly as bad as It was, but it’s there. I pulled a load of cattle with it and just like last time, the knock showed up after pulling. Something about hooking on to a load seems to bring it out. It is not very noticeable at all right now, so I’m thinking if I take it somewhere at this point it will be the same as last time. Somebody on here suggested unplugging injectors one at a time. Can I do that and go for a test drive? I can’t get it to make the knock at all while it’s in park. It has to be under load. If I decide to keep driving it hoping to make the knock more steady, am I asking for piston trouble if it is an injector blockage?

Any replies or suggestions are greatly appreciated.
 

·
Registered
2017 l5p Chevrolet 2500 LT CC
Joined
·
76 Posts
Discussion Starter · #23 ·
I am going to update this, hoping somebody has some ideas for me.

I took my truck back to the shop. This time they were able to duplicate the knock. It went away when they shut down cylinder 5. They pulled that injector and bench tested it. It passed, but not by much. I still had them replace all the injectors.

After replacing the injectors, the truck still had a fuel knock on cylinder 5. Then the shop flashed the original gm programming onto the ecm. The knock went away. Then they flashed another tuners programming onto it. The knock still wasn’t there. Then they flashed the programming that I had on it back onto it. The knock was gone.

So everything was good for around 3000 miles. Now my knock is back just like it was before. Different tuning was flashed onto it. The knock is still there, but maybe not as bad. That is where I am at with this now.

The knock is there around 1400 rpm on acceleration. If you rev it to 1400 when in park or neutral, it is not there. Only in drive. When decelerating it is not there.

Does anybody have any ideas? This is driving me CRAZY! The tuning company says that if it was tuning, it would not go away. They are working with me to try and resolve this, even though they really don’t think it’s tuning related. Could an ECM going bad start corrupting files? Wouldn’t I have other stuff going on? Any ideas would be GREATLY appreciated.
 

·
Registered
2013 Chevy Silverado 2500 HD
Joined
·
5 Posts
I am going to update this, hoping somebody has some ideas for me.

I took my truck back to the shop. This time they were able to duplicate the knock. It went away when they shut down cylinder 5. They pulled that injector and bench tested it. It passed, but not by much. I still had them replace all the injectors.

After replacing the injectors, the truck still had a fuel knock on cylinder 5. Then the shop flashed the original gm programming onto the ecm. The knock went away. Then they flashed another tuners programming onto it. The knock still wasn’t there. Then they flashed the programming that I had on it back onto it. The knock was gone.

So everything was good for around 3000 miles. Now my knock is back just like it was before. Different tuning was flashed onto it. The knock is still there, but maybe not as bad. That is where I am at with this now.

The knock is there around 1400 rpm on acceleration. If you rev it to 1400 when in park or neutral, it is not there. Only in drive. When decelerating it is not there.

Does anybody have any ideas? This is driving me CRAZY! The tuning company says that if it was tuning, it would not go away. They are working with me to try and resolve this, even though they really don’t think it’s tuning related. Could an ECM going bad start corrupting files? Wouldn’t I have other stuff going on? Any ideas would be GREATLY appreciated.
Did you ever solve this issue?? I’m having almost the exact same issues with my LML.
 

·
Registered
2017 l5p Chevrolet 2500 LT CC
Joined
·
76 Posts
Discussion Starter · #25 ·
No. I never got it figured out. It came down to either live with it or tear the engine down hoping to find something. I traded up to a l5p and couldn’t be happier so far.

Good luck to you on figuring out your issue. If you do get it solved please post your fix. It still bothers me that I never got mine fixed.


Sent from my iPhone using Tapatalk
 
21 - 25 of 25 Posts
Top