2006 3500 engine sounding rough between 2600-3000 RPM

anfernyrocks

New member
Hi, all!

I'm new to the forum and new to sprinters (and diesel). I have a 3500 T1N that has a rough noise between 2600-3000 rpm. The noise gets more noticeable with more throttle, but it's pretty much constant at highway speeds. It's totally throttle dependant; if I release the throttle the sound stops immediately. The guy that sold it to me thought it was the alternator going so he replaced it but the sound hasn't changed.

It doesn't have black death, though I think it might have before I bought it. I found only one other post with someone describing this issue. I PMed him but I figured there wouldn't be any harm in asking others. Thanks in advance! You all have already been a huge resource for me!
 

anfernyrocks

New member
The noise just sounds like the engine working extra hard. There isn't any extra vibration, I haven't been suffering any poor fuel mileage or a lack of power.

 

trc.rhubarb

Well-known member
There is a partial limp home that will limit RPM mostly to 3k and have about half the turbo running.
You can do 75mph on flat ground but hills become tough as does acceleration.

It gets pretty loud when that happens.

How is the van running other than the noise? Does it kick down when you put your foot in it? Can you rev over 3k?
 

anfernyrocks

New member
It runs fine. It didn't have any problems going up hill, it just sounds strained. It pulls pretty well for a 22' long van. I'll have to go out and see if it does rev past 3000, but I'm almost certain it does. I know for a fact it does when it isn't under load. If not, what then?
 

anfernyrocks

New member
No codes. Air filter clean. As far as I k ow I don't have any boost leaks. No greasy spots. Not sure really how to determine if the egr is working correctly. I will say that there is a faint diesel smell in the cabin. 20200805_183717.jpg20200805_183628.jpg
 

anfernyrocks

New member
I did find one post where veganxxx said he had a similar problem. I'm just waiting on a PM back from him for any insight.
 

anfernyrocks

New member
Doing that today. I think I'm gonna remove my injectors and have them inspected at a bosch diesel place. You all have been a huge help. Thanks so much!
 

anfernyrocks

New member
So when I spoke to the gentlemen that sold me the sprinter the told me that they had all the injectors tested and they all passed, apparently. I'm really confused now. I guess my only real option is to start pulling the fuel system apart to see if I find any signs on black death...bummer
 

anfernyrocks

New member

I decided to pull the engine cover and put the microphone next to all 5 injectors. They don't sound all that dissimilar but 3 and 4 do seem to be a little "tinny". I also found that I can't replicate the noise unless it's under load. What do you all think? Thanks again for playing, everyone!

Edit: I was, however, able to confirm that the egr is fine and the engine happily revs past 3500, so doesn't seem to be in any sort of limp mode.
 
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anfernyrocks

New member
You just need to remove the plastic cover on the top of the engine to check for black death. No fuel system disassembly is necessary.
No black death. I think the oil smell is partially due to the black death that it used to have. At least I hope. Two of the injectors sound a little more chattery than the others. I posted a video, bit it might be useless. The shop said they had the injectors tested and they all passed; can injectors just be noisy and still operational?
 

Duckmang

Qualified Personel
If the injectors were pulled to test, one has to wonder if they were installed back in their original positions... If they were thrown back in willy-nilly then the injector codings could be causing uneven running.
 

anfernyrocks

New member
If the injectors were pulled to test, one has to wonder if they were installed back in their original positions... If they were thrown back in willy-nilly then the injector codings could be causing uneven running.
Would that cause a code? My other idea is that the seats weren't cleaned up all the way (or the washers were reused) and that black death 2, diesel boogaloo is right around the corner. Either way, it looks like I'm pulling all the injectors out and checking. Might as well have them tested by a Bosch facility just to be safe.
 

Duckmang

Qualified Personel
No code, necessarily. Each injector has a coding string to tell the CDI how to activate it to get the desired fuel delivery. Its unique for each injector.
 

anfernyrocks

New member
No code, necessarily. Each injector has a coding string to tell the CDI how to activate it to get the desired fuel delivery. Its unique for each injector.
So if I replace injectors do I need to get it towed to a shop or dealer to get it coded or can I limp it there?
 

Midwestdrifter

Engineer In Residence
Miscoded injectors will be noticeable at idle, but I don't think its going to cause engine noise only under high load, as the miscalibration is going to be across the whole throttle range.
 

anfernyrocks

New member
Miscoded injectors will be noticeable at idle, but I don't think its going to cause engine noise only under high load, as the miscalibration is going to be across the whole throttle range.
I spoke to a Bosch diesel shop this morning and without knowing anything about Sprinters he immediately said "it sounds like you have gases coming out around the injectors through the seals. The crusher washers were reused or they were placed on to an improperly cleaned head or injector.". So basically, black death. So I'm bringing my injectors to be tested on their machine and I'm gonna really get in there and clean it.
 

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