acceleration knock

[danzick]

Hey guys. ive been daily driving this new engine for a bit now. I am sure I have a knock of some sort under acceleration that is not normal. Any ideas where I could start looking? it Idles nicely, no excessive smoke at idle, and cold starts like a dream with hardly any smoke. Under boost, it sounds very nice and smooth. It sounds like a 7.3L powerstroke until boost comes on. Its driving me crazy! I dont think its an engine knock. I would think that would show up at any or all RPM's. Injectors? did I mess up the valve lash adjustment? I have one injector, #3 that goes in and out of spec. I tried shutting them off one at a time while accelerating, and while it ran like crap with only 7 cylinders, the knock was always there. I'm afraid to pull a trailer, or drive on the highway for extended periods of time until I figure this out. I should also add I have been working with PPEI and they are confident its not the tuning. I have tried 2 different tunes from him and sent him a log with no help in the knock.

 

[2004LB7]

can't really hear anything out of ordinary

 

[08lmm72mm]

Try swapping injectors 3 & 5 see if the problem moves to another hole, if it does its the injector.

 

[danzick]

Try swapping injectors 3 & 5 see if the problem moves to another hole, if it does its the injector.

thats a lot of work on an lb7! Dan at dan's diesel says it does sound l like injectors to him. He thinks im ok to continue to drive it for a bit. I would just hate to go through all the hassle to mess with injectors and its not the problem.

 

[danzick]

can't really hear anything out of ordinary

its hard to hear on video. Its very pronounced in person. It reminds me of when I had a timing rattle a few years back that Kory fixed for me, but he has assured me its not the problem this time.

 

[2004LB7]

its hard to hear on video. Its very pronounced in person. It reminds me of when I had a timing rattle a few years back that Kory fixed for me, but he has assured me its not the problem this time.

yeah, videos are like that.

if it's not software related then its hardware. post up your balance and main rates here and maybe one of us can see something

 

[dndj]

I could definitely hear it right near the end of the 2nd video, starting at 0:45 when you turned the left hand corner and accelerated. I can't offer any useful advice for you though no experience in this space.

 

[08lmm72mm]

thats a lot of work on an lb7! Dan at dan's diesel says it does sound l like injectors to him. He thinks im ok to continue to drive it for a bit. I would just hate to go through all the hassle to mess with injectors and its not the problem.

Well the problem won't disappear on its own haha and if an injector keeps going in and out of spec I'd bet it's the Injector or leaking boost past the copper washer, or the wiring to thar injector.

 

[danzick]

any way I can check the wiring? I hadn't thought of that. I checked it again this morning. They are just so damned random. Worst is +9.8 at 12mm main fuel. Yesterday, the main fuel rate was 8-9mm. And I had this? Than, give it a few minutes and they will all be +/- 2 or better at 8-9mm. First image was today at 12mm. Second one was yesterday at 8-9mm.

 

[Bdsankey]

Sure sounds like an injector to me. What is rail pressure doing during that time? Is the file turning pilot injection off?

 

[Yngdmax92]

Most definitely sounds like some worn out injectors

 

[08lmm72mm]

Looks like bad injectors what's the history on them? I don't know much about LB7s but isn't there wiring issues with the ficm that can cause erratic balances rates and sounds like you are hearing ? I wouldn't want to drive it with balance rates like those.

 

[2004LB7]

based on the balance rates and reported main rate I'd say injectors too

 

[2004LB7]

Looks like bad injectors what's the history on them? I don't know much about LB7s but isn't there wiring issues with the ficm that can cause erratic balances rates and sounds like you are hearing ?

I believe that was mainly an issue with the LLY and sometimes the LBZ. it could happen with the LB7 but really only if the terminal nut was loose. wasn't too common unless it was shortly after replacing the injectors. and I think it would throw injector codes

 

[danzick]

terminal nut? I mean I did just go through the engine, so just about every nut and bolt has been turned, but I have no codes. Injectors were LDS remans back in 2012. They had about 20k on them when Dans diesel calibrated them and put the nozzles on. They were fine before I rebuilt the engine. Thats why I find it so strange they are no good all of the sudden. I just ordered 70% overs from brad. I sure hope this is the end of the trucks problems! it is bleeding me dry.

 

[Chevy1925]

terminal nut? I mean I did just go through the engine, so just about every nut and bolt has been turned, but I have no codes. Injectors were LDS remans back in 2012. They had about 20k on them when Dans diesel calibrated them and put the nozzles on. They were fine before I rebuilt the engine. Thats why I find it so strange they are no good all of the sudden. I just ordered 70% overs from brad. I sure hope this is the end of the trucks problems! it is bleeding me dry.

well throwing parts at it will do that.

 

[2004LB7]

terminal nut? I mean I did just go through the engine, so just about every nut and bolt has been turned, but I have no codes. Injectors were LDS remans back in 2012. They had about 20k on them when Dans diesel calibrated them and put the nozzles on. They were fine before I rebuilt the engine. Thats why I find it so strange they are no good all of the sudden. I just ordered 70% overs from brad. I sure hope this is the end of the trucks problems! it is bleeding me dry.

on the LB7 injectors the connection is made by threaded studs or terminals protruding from the top of the solenoid. the wire or cable is fixed to the terminal via a nut that secures it. if this nut is not properly torqued it can work loose under the valve covers where it is hard to check. it can give bad injector codes, bad balance rates etc. somewhat similar to the bad harness connection of the LLY.

 

[OleBlackyLBZ]

terminal nut? I mean I did just go through the engine, so just about every nut and bolt has been turned, but I have no codes. Injectors were LDS remans back in 2012. They had about 20k on them when Dans diesel calibrated them and put the nozzles on. They were fine before I rebuilt the engine. Thats why I find it so strange they are no good all of the sudden. I just ordered 70% overs from brad. I sure hope this is the end of the trucks problems! it is bleeding me dry.

Lincoln diesel does good work, id bet almost anything those injectors are fine if they only have 20K on them. Mine have over 40K on them. If the problem goes away when you install the new ones more than likely it was just an install error the first time.

 

[danzick]

on the LB7 injectors the connection is made by threaded studs or terminals protruding from the top of the solenoid. the wire or cable is fixed to the terminal via a nut that secures it. if this nut is not properly torqued it can work loose under the valve covers where it is hard to check. it can give bad injector codes, bad balance rates etc. somewhat similar to the bad harness connection of the LLY.

oh I gotcha. I dont think thats the issue. its not that kind of intermittent. Pretty much constant with knocking until boost comes on. Its not really random.

 

[danzick]

well throwing parts at it will do that.

any other suggestions? I dont normally like "throwing parts" at things, but everything seems to point towards injectors. Testing them cost me like 500 bucks last time so I'm trying other ways to figure it out.