Yeah, I've been well aware of the screwy fuel supply on the 5.9L ISB's. 106k flawless miles on mine, and it also got to put up with me running homebrew biodiesel in it for a while.

I would be surprised that they would wait untill half of the injectors were down to put the engine out of service. One torching injector is enough to make very expensive repairs if it isn't fixed.

I would as a general rule check injector first as they are typically the easiest item to remove and test. I would then dig deeper if they all passed.

Then again, I'm not a Cummins repair tech (But I did sleep at a holiday in express last night!)

No leaks and all compression is above 300. The fastest way to find a leak is windex. I did pull the #1 PC and even bought a set of new injectors for it. No problems were found.

I just a new borescope last month, I'm just waiting for enough downtime to pull all the injectors and PC's to see what's going on inside the cylinder.

You bought one?? how much?

I got it for $200.

I was going to buy one new but Russ, our Cornwell dealer, had a trade-in 18" ProVision Flexible Borescope that was never used.

HERE is an example of what I got.

nice . i did not know something like this existed. the onlything i had seen was the one that is hooked up to the tv like monitor. this is cool

Hey man i got the same problem. Fixing leaks did not fix the nailing. So if you fix this nailing please let me know how you fixed it.

it seems no one can get to the bottom of all these nailing issues, the threads end with no conclusion reached or no one posting what fixed there nailing engine.this is the 4th thread on the same issue.
has anybody fixed there nailing? if so please post what was done to fix.

i am taking my 1990 300 TD to a shop tomorrow as i have tried so many fixes surgested on many threads but nailing continues.
would love not to have car in shop but dont want to damage my engine as it runs great over 1700rpm, even get over 40mpg on a hwy run.

cheers.

I have been finding the same thing.... Nailing in one cylinder threads are never completed or never figured out... I have a very similar issue.

For my '87 300SDL, nailing was cured by replacing the cracked #14 head with a new #22 head. The IP, prechambers and injectors were kept with the new head so my conclusion the new head or at least the new head gasket resolved the nailing.

owain, I'm guessing you mean you have a '90 300D. It's not likely an OM602 has a cracked head but a failed head gasket, by way of oil leaking into the #1 cylinder, is unfortunately common.

Wagnerwerks, I'm guessing from another post that you have a 78-85 300SD. It's not likely an OM617 has a cracked head or a failed head gasket.

For both of you, I suggest isolating the nailing by loosening the injector lines one at a time. The nailing injector should quiet when it loses fuel pressure. Swap the nailing injector with another injector in the engine to see if the noise follows the injector or stays with the cylinder. That information will give the forum plenty to chew on.

Some folks, maybe only a few, have cleared nailing by running a bottle or two of LiquiMoly/LubroMoly Diesel Purge. There's a process to this - it's not effective if you dump it into the fuel tank or let the return line continue directly to the fuel tank while purging.

Sixto
87 300D^2

Looks like its still running.
Mercedes Forum - Mercedes Benz Enthusiast Forums - View Profile: ForcedInduction
I'll send him a PM and see if he ever figured it out.

"Turns out it was never fuel nailing but a bad #1 cylinder wrist pin bushing causing piston slap. Hasn't really been functional problem though, just an audible annoyance. The engine is still running strong 9 years and 65k miles later!"

Here are a set of injectors that where loaded with glop and eroded to junk.
The nailing was abrupt and spectacular, it fooled several mechanics into thinking a rod bearing had failed.
Welcome to the fleet 1976 W115.114 "300D" dark Green

Rebuilding the injectors with fresh nozzles totally eliminated the nailing.


.

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Just a thought I thougt my 602 was nailing had done it since I got it years ago one day my belt drive tensioner damper broke the attachment ring off and now my 602 is quiet at idle (after I removed to damper body which was making hellacious racket) and I had put a whole tensioner arm and damper on new when I did the head work some years ago of course was a uro part but the tensioner arm and bearings are still good lmao

In my experience, a failed belt tensioner dampner sounds like a woodpecker. If you press down on the top bushing and it quiets, that's your issue. Nailing sounds like smacking an anvil with a mini sledge. Knocking from the lower end sound like a hammer smacking the side of the engine block. Failed lifters on a 60x sound like a quarter being tapped on a glass coffee table or granite counter top. Regular diesel clatter sounds lopey in nature and there isn't one particular part of the chorus that stands out from all the rest. It just sounds like peaceful, even, consistent knocking that's "soft" compared to a rod bearing going bad. My OM601 with rebuilt injectors, new timing chain tensioner, and new hydraulic lifters is VERY quiet and well mannered. I can go through a drive through without being asked to shut the car off. I'm sure if I had the underbody panels in place, and fashioned closed cell enclosures for the injectors and possibly IP, and a new hood pad installed, the car would be INCREDIBLY quiet.

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