Well, I got the '81 300D back together today, started it up, got oil pressure, no leaks, generally okay.

Number one cylinder refuses to fire. I ran it a few minutes, the miss didn't go away. Worried to death that there was a hole with no compression, I pulled the injectors and checked compression, 370 pounds on all cylinders, whew!

Before pulling the injectors for the compression test I cracked open each line at the injector and the miss was obviously on number one cylinder. This is where the miss was before I took it apart, but at that time I had less than 100 PSI compression on that cylinder.

When pulling the injectors, 2 through 5 had a black sooty powder coating on the tips. Number one did not. I took the number one injector apart, everything looked okay so I put it back together and back in the car. Still had the miss.

I went out and robbed an injector from the 240D and put it in number one. Still had the miss.

When I crack open the line at number one, fuel sputters out. I took out the plunger from number one nozzle when setting start of delivery while the engine was on the stand, but I'm quite certain I put it back in the way it came out. Is there a way to get it in wrong which would cause this?

Do I need to take the pump to the shop?

Any ideas or things to check will be very much appreciated.

Good news, it looks like the engine itself is going to be okay. With 370 pounds all the way across, I can't imagine that I'll have to open it up again for a long time.

I drove it down the road and it wouldn't shift past second. It was not completely full of ATF. Will this make it not shift, or is it strictly in the vacuum switch monstrosity atop the valve cover. I will get ATF tomorrow and top it off. I'm not near as worried about fixing the transmission as I am about the miss.

Thanks to all,

Larry - take a look at the first couple pages of the "Fuel and Exhaust System" chapter in the Haynes manual. There is a picture of the orientation of the fuel injector valve/spring. See if this is the way it is together.
Does the "start of delivery" time out alright? If you put it close to top dead center on the #1 and pump the hand pump do you get a steady flow from the spider pipe at the injector?
glad to hear everything else is ok

__________________
Jim

Larry:

I've got an 87 300D doing the same thing at idle, seems to work much better at speed, though.

Does #1 knock at all? If not, you are not delivering fuel at pressure to the nozzle. The nozzle can be fine and still not deliver fuel if insufficient pressure is delivered to lift the pintle.

I don't know if you can put the spring/pressure valve element in upside down, but if you did (or dropped the spring) it won't fire at idle, or even at speed, since the pressure in the line goes back down the pump element. It will spray out with no back pressure, though -- the "pressure valve" is actually a check valve to maintain pressure in the injector.

I would take the pressure element out again and check it carefully for scoring -- it seats on a flange and has a "stem" that sticks up that the spring fits over. Spring goes on top, toward the deliver line. If the guy before you had it upside down and you put it back that way, it still won't work. Much easier to fix than the IP.

You can test the injector and pump by taking the injector out and attaching the line and cranking or running the engine, but BE CAREFULL, please -- the IP will run the fuel straight through your skin if you get any body parts near the operating end, and you will be making huge clouds of fuel spray. It will tell you if the IP is actually pushing fuel out the nozzle, though.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Yes, the start of delivery is set on the money, and yes I did get it retarded to a point of a steady stream before setting it to the point of a drip. I'm quite confident that it is timed right.

I guess I will pull the pintle and spring to check them.

Any more thoughts are welcome,

It very well could be a fault with the delivery valve and or the cam inside of the injection pump. I would take out the injector, bolt it to the line (bent upward) and allow it to spray into a cup while the engine runs. This way you can see what is happening.
(Diesel is not very volatile and will not explode like this.

__________________
Benzmac:
Donnie Drummonds
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 11 YRS

THE MISS IS GONE!

I took the number one line off, removed as much as I could below there, cleaned everything as best I could, put it all back in and the miss is gone.

Now the problem is an occasional cylinder that doesn't fire, the RPM's are slow to come up when you goose the throttle and lots of smoke. It could be that the smoke is just the oil in cylinders, put there in assembly is still burning off, but I don't think so.

I sure thought I had the start of delivery exactly on the money, but it acts like a gas engine with retarded timing as far as the RPM's being slow to come up. I'm not sure what the smoke is about.

I'll keep hammering on it after the smoke clears out of my shop. I have 16 foot doors at both ends of the shop, both wide open and the smoke is still in the air.

Have a great day 'cause mine's gettin' better,

Larry:

So very cool, I love cheap easy fixes! I'm going to borrow the tool to take the pressure valves out of my 300D next week.

Sounds like air in the IP, or maybe a sticky injection timer -- slow rpm rise and smoke at idle can be fast injection timing -- if the timer sticks when you wind it up, you get fast injection timing at idle (broken springs in the timer can do this too!). It's under the vacuum pump.

Good luck!

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

I didn't add the latest to this thread.

After I ran the engine some, the smoke cleared up and the RPM's now come up well when you goose it.

The problem now is an occasional missed beat. It's not a set rhythym like a dead cylinder, but occasionally a cylinder just misfires, this is at idle.

The transmission is not kicking down now. I broke the nipple on the vacuum tube that supplies the vacuum shift mechanism. I temporarily plugged it 'til I can get the right parts. I then used a tee from the other vacuum supply for the transmission shift. It now shifts through the gears and cruises in high, but it will not kick down when you floor it.

Thanks everyone for all the help,

Larry:

Did you forget to reconnect the kickdown switch wire? It won't downshift at full throttle if the switch isn't connected or isn't working.

If you didn't get the injectors tested, they can cause a miss at idle, along with smoke. Run some Redline or similar through if you don't want to pull them (again!) and see what that does for you.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

psfred,

Thanks for the help. I, for the life of me, cannot remember any kickdown switch or wire. I would assume that it is somewhere on the vacuum switch contraption on top of the valve cover. I don't remember taking off such a wire, and I could swear that I have reconnected everything.

I did notice an electrical connector on the transmission with about 6 or 8 wires on it. I was surprised at that.

I have thought about the injectors. I don't mind at all pulling them, there's nothing to that. I just don't know where I can have them tested. It would cost another $225 or so for a new set, so I'm trying to do what I can under my current financial circumstances. Thanks for the advice.

Have a great day,

Larry:

Kickdown switch is under the top of the accelerator pedal. You should be able to feel it click under your foot.

The wire is on the right front corner on a W115 chassis and next to the neutral safety switch on the W123. It is a one-wire connection, simple solenoid valve. Should connect to an insulated connector of some sort, usualy with a screw.

Any diesel injection service can test the injectors for you, shouldn't be much to test them. Replacements are more expensive. Try the RedLine or Diesel Purge -- they are likely all carboned up from the poor running condition prior to rebuilding the engine.

I'm hoping I can cure my miss with a cleaning, too! Otherwise it's engine overhaul time, or worse, IP overhaul!

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

psf - why do you say the injection pump rebuild is worse?

__________________
Jim

Complete rebuild of the IP starts at about $1500 for a four, goes up to $2500 or more for a 603. Cannot be done by the DIY type, under any circumstances.

I spent $750 on my VE pump from the Volvo, and consider that cheap since there is only one piston/sleeve set. To replace the cam, pistons, and sleeves in the 603, plus calibration and seals, etc would be on the order of $3000 or so -- costs $250 to put it on the stand and check it!

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

I've seen rebuilt pumps for under $1,000 exchange for the 617 motors. I would assume that they would be less for the four cylinder. Good news is they've always held up good for me. Have I just been lucky?

Have a great day,

Larry:

Depends upon what needs to be done.

These things tend to go forever unless they are run dry too much or get gasoline in them, on unfiltered fuel. My indy checked on a rebuild for another customer recently and was quoted "up to $2500" -- this doesn't inlcude the labor for R&R, either, which isn't exactly a breeze on the 603.

I suppose $1000 exhange "rebuild" is simply a returned pump with cleaning and calibration, with the cost of new piston/sleeve/spring sets distributed amongst all the pumps that simply needed new seals, etc. If I were in the business, that is what I would do -- I imagine a great number of pumps are traded in for relatively minor problems. Cam, piston/sleeve sets, and springs would probably be much more -- about $400 per set, who known what for the cam! A Stanadyne single piston pump with governor replacement (typical US engine pump, very common) is about $500 these days, so multiply by the number of piston/sleeve sets involved....!

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!