Hey guys, quicky question.
I searched into disassembly/inspection and rebuild/cleaning of injectors as I suspect I may be having issues with them after my last test drive ( that and unknown engine history/mileage+sitting for 4 yrs).
Once satisified I knew what to do, I took the old injectors out of my blown 616 to experiment on before I dig into my car, upon disassembly, I saw what first looked like a carbon deposit in the tip of the pintle that protrudes thru the end of the nozzle. After trying to rub it off unsuccessfully I got my dentist pick and probed at it, only to discover it's a little hole, found one
180* out from that one as well, was able to pass a very very fine precision drill (about human hair sized) thru the hole to clear it out.
Now my question:
At the very tip of the pintle, it looks like there is a hole that tees into the other one, but I can't seem to run anything thru it, is it just an indentation or is it really a tiny passage? I assume it has to do with the proper atomizing of the fuel, so if it's a hole I will need to address cleaning it.
-Chris

That little bit poking out of the nozzle is the point of the pintle. It should look like that.

You will need to have that nozzle replaced/rebuilt now.

Mustang,

The pintle holes "T", just as you surmised. Check the service manual(mine's at home; I'm not ), but I recall 0.18mm as the diameter of the clean out tool. It's not just an indentation.

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1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)

Dont pic the pintal.

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Thanks for the input guys. This is why I started with my "experimental" injectors before I mess with the ones I need to fix, now all I gotta do is figure out a good way to clean that hole without damaging it, and I'll be set for redoing the "good" ones. Got a new can of carby cleaner parts dip sitting on the shelf in the shop, might be able to make that work, dip it for an hour or so....

I noticed on D.G.'s injector repair notes it was mentioned something about heat shield/sealing washers, are those on all the 617 & 616 engines? I noticed there were none in that old 616 I pulled apart.

I am curious now too, I tried to use compressed air in the hole to "blow" the prechambers out after removing the ring nut above it (yes I removed the glow plugs first, and blocked the holes shut). Has anyone found a good way to remove them without pulling the head?

The reason I am getting into all of this is, aside from already mentioned unknown history and having sat, I am still having issues getting it to run correctly, and it varies by trip. One day was just dead on power & no smoke, the next trip it had better power but you could see nothing in the rearview it was smoking so bad, had a dead miss after warmed up. Next trip it ran like it had never run, set you back in the seat, no smoke, but had that dead miss again after heating up. It has what feels like a miss also around the 1000 rpm area whether cold or hot. Right now I am just trying to establish known engine condition and eliminate variables, I suspect a bad injector or weak cylinder due to the missing. It has all brand new filters, a new thermostat, and the tank/screen has been inspected. I plan to check compression when I get into it as well. The engine I'm trying to save is a 617, no turbo, unknown year, stabbed into an '80 240D. I will post the engine number tomorrow and hopefully someone will recognize the vintage.
-Chris

You can pull the prechamber without pulling the head. Your options are the pricey MB tools or you can make your own. I went the latter route. Before you go to the trouble, take a peek down the injector hole and see if the ball is still there. In my 240D, 2 of the 4 were missing the ball and when I pulled them out, the sides were shattered. They looked terrible and I was sure they were why my car ran like crap. Replaced the 2 broken ones and it ran exactly the same as before.

So, check for the balls. If they are there, its a fairly safe to assume that the PC are not causing your problems. If the balls are missing, then you should pull and replace the chamber.

How do you make your own tool for this?! Just curious...

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First go look at a manual, on-line or otherwise and look in the injector repair/replace section. That will give you the size of the pintle cleaning needle.

Then call to find a Bosch dealer near you:
Robert Bosch Corporation
2800 S. 25th Avenue
Broadview, Illinois 60155
(708) 865-5200

I can get part numbers if you want but it will have to wait until I get home.

DAnny

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The PC tool is made from a bicycle crank pulling tool. That tool fits the internal threads of the PC. The creative part is getting a platform to pull against to bring the PC up and out. I made one out of a u shaped piece of steel. It looked ugly but it yanked out the 2 PC's and could prolly do the other 2 before it broke.

try soaking the carbonized parts in transmission fluid to loosen and remove carbon from them.

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The manual says after Nov. 1981 0.20mm.
Cleaning needle size 0.18mm, part # 0 986 611 158
Before Nov. 1981 0.15mm
Cleaning needle size 0.13mm, part# 0 986 611 156

It also says "Using brass brush, remove carbon deposits from end face of nozzle body, chiefly around nozzle orifice."
And " Clean nozzle needle with brass brush."

Danny

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1984 300SD Turbo Diesel 150,000 miles

OBK member #23

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Brass eh?...whoopsy.....well, it was a soft brush anyway....(for instruments)

I got the engine number this evening, 617 912 10 194 955 anyone know what year it is and/or what it came out of? I noted an '86 vintage fuel hose on it, but that could have been replaced in the past too.
-Chris