Well, I'm very pleased to report that 400 additional miles have now eliminated the injector knock to the point where I can't discern any difference between cylinders. Just sounds like it's typical very quiet idle that it always had.

It also provided a stunning 31.5 mpg on the trip from Raleigh to VA and back to south Jersey. 90% of the drive was at 65 mph with various stoplights along the route. Probably hit at least 30 full stops during the trip. 10% of the trip was a steady 70 mph.

I'll bet that Raleigh, NC doesn't get the winter fuel!!

Cool, I like it when problems go away by themselves.

Its great to hear that its normal again, Brian! Its also interesting to see what different ideas people come up with as possible scenarios. INcluding myself.
Its also great when noises go away on their own.
I had a real noisy engine after getting my $450 '87 300D project running. I had put a lot of time and $$ in to it and after I discovered that the Trap Oxidizer (make that Nasty T.O.) was plugged I took it to the dealer for its trapectomy. All that time it ran strong but it had a loud nailing. I rechecked timing with the RIV tool and it was spot on. I swapped another set of injectors onto it but still the same darned nailing. It was very pronounced and bothered me a lot having just installed all the new parts I could afford to make sure this was going to be a reliable engine: it had new rings, a rebuilt head, new lifters, a new vac pump, new radiator, NEW water pump, new oil cooler lines, new oil cooler because I stripped the threads trying to get the hose fittings off, etc. etc. then what a let down with all the clatter, I was really embarassed to start it up.

Then I started thinking and I remembered the car had no gas cap on it when I got it. It had been sitting out for almost 2 years. The PO had some kids around and they may have put water in the the fuel tank because when I pumped some fuel out into a small glass jar I could see it had a milky appearance.
I pumped most of the fuel into a 55 gal drum then filled the tank with a bottle of RedLine catalyst and fresh fuel. That helped some but it was still nailing. After I ran thru two tanks of fuel and redline treatment and some Diesel Power Kleen stuff (not sure if that's the proper name) the noise slowly dimished and its completely normal now. I'll never understand what was going on. Maybe the rings were seating in also.

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!

There's a theory that the injector pintal has a sweet spot and that if dismantled or flushed and tested on the bench, will turn the pintal out of the sweet spot and make the nailing noise when back in service......just a theory...just like evolution.



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[http://languageandgrammar.com/2008/01/14/youve-got-problems-not-issues/ ]

"A liberal is someone who feels they owe a great debt to their fellow man, which debt he proposes to pay off with your money."

I think this explanation is for situations that lack a proper answer based upon combustion theory.

I'm leaning toward possible air that gets trapped in the hard lines. Maybe it takes a few miles to get rid of it all. I don't see how it's possible to damage the injector and, within 600 miles, have it repair itself via the use of a small amount of Power Service conditioner.

I did crack the hard line and attempt to bleed any and all air, so, this theory can be quickly shot down...........

[QUOTE=dkveuro;1361278]There's a theory that the injector pintal has a sweet spot and that if dismantled or flushed and tested on the bench, will turn the pintal out of the sweet spot and make the nailing noise when back in service......just a theory...just like evolution.

I would give it a rating of a little higher than just a theory. There are no rotational devices incorporated for instance . It would not seem unreasonable to upset wear patterns as well. Providing there was enough uneven wear to start with. With very little or no wear probably no audable results. Let a fair amount of wear be present though and perhaps a much different story. This is why we observe the spray pattern and do dripdown testing?

No kidding. After I had the injectors rebuilt on my wagon, it sounded terrible and I was seriously questioning my actions. It took about 750 miles but eventually settled down nicely.

If I were you Brian, as long as there are not any power issues, I think I'd run a few more miles/tanks through her before making any move.

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Never a dull moment at Berry Hill Farm.

Well, Randy, you're exactly right. After 600 miles, I've got no moves to make.

Nice to have a problem that fixes itself!

If your getting 31.5mpg you would be crazy to even consider touching those injectors!

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

Yep, I couldn't believe it.

The gauge was at 1/2 tank after 325 miles and I had another 235 to go and was a bit concerned with the total distance.

Not an issue.

561 miles

17.65 gallons right to the cap.

Wow I never got over 30 with my SDL, no matter what I do she won't break that mark.

Next road trip I'm going to try like crazy. Around town if the mileage is 21-23 I'm happy.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

My only other change was to increase the tire pressure slightly. It now carries 34 in the back and 32 in the front.

I hadn't checked it in months and the cold weather had dropped them all by about 4 psi.

I'll never see 30 again until the summer fuel returns.

I run 32 or 34 all the way around on the L all the time.

Currantly the L is getting great mileage, its been sitting un touched under its cover for the past two months. I probably should check on it... I bet it still has a full tank!

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

What happened.........mechanic boot you out of the #2 space in the garage??

Nope, his truck wont fit so its all mine!! Even the new truck that he wants to buy is to big! Score!

We sold the boat, so I may get that bay year round now. If I do I'll install an auto door opener as thanks.

I have also laid claim to that side of the driveway, so I can technically keep two MB's in service now...don't tell the parents that though.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200