smoke & missing at startup - PeachParts Mercedes-Benz Forum

JimmyL · #1 08-13-2004, 01:14 AM

My '80 300TD just started doing this. If the car sits for more than 3 or 4 hours, or especially first thing in the morning, it smokes HEAVILY (white) and will not idle for a minute or 2. It starts immediately, no glow plug issue, but right away starts to sputter and smoke. After a couple of minutes, it holds idle and doesn't smoke any more than normal.
I have adjusted the valves (I even pulled the valve cover and inspected my valve adjustments again), I drained the 'FUEL' tank(PEH, that's for you buddy), I removed tank filter which was spotless, I changed fuel filters, I have run several tanks of diesel, with biocide/additive. No change at all. I'm at a loss at this point...
Jimmy

bill murrow · #2 08-13-2004, 07:38 AM

Jimmy, I think the white indicates water--blue/oil---black/fuel.

Have you checked your coolant? Low? Oil in coolant??

I'm no expert--what do you experts think????

Good luck--

Cheers,

Bill

tlbro1 · #3 08-13-2004, 11:05 AM

I think water is invading the combustion chamber,from where will be any bodys guess,
good luck.
Tom Brown
Va Section

P.E.Haiges · #4 08-13-2004, 11:27 AM

JimmyL,

Do a resistance on the GP. Replace any that don't read about 0.7 ohms.

P E H

phantoms · #5 08-13-2004, 08:13 PM

Does it also nail a little after first cranking it? It may be a leaking injector.

franklyspeaking · #6 08-13-2004, 08:33 PM

I think you have a bad glow plug or two. Even though it starts right up, it's not fully firing on one or two cylinders when its cold. If it were coolant, it wouldn't go away, when it warms up.

My $.02 worth....good luck!

JimmyL · #7 08-14-2004, 02:10 AM

I've been meaning to ask this for a while, and now is a good time. What is "nailing"?
Thanks for all the replies so far. JL

phantoms · #8 08-15-2004, 09:37 AM

Nailing is a fuel related knock. It's a little higher pitched (usually) than a bearing knock.

JimmyL · #9 08-15-2004, 10:13 PM

All glow plugs ohm out at .4 to .5 ohms. It seems to be getting worse. Today it died while I was trying to keep it going. And for about 2-3 minutes it is sputtering and shaking and smoking......After that I drove it around the roads here and it runs fine. I'm still at a loss to know how to proceed (or procede?). JL

sublettm · #10 08-15-2004, 10:18 PM

When you figure this one out, let me know what fixed it. My wife's has had this problem for quite some time now. Once it warms up, it is smooth as silk, but upon initial start-up, it shakes and rattles and smokes a little. Would love to solve this problem! I too have replaced everything I can think of which would cause this problem. I don't think it is GP related since it fires right up...even in the winter time.

Mike

BenzRepair · #11 08-15-2004, 10:40 PM

It's possible, like others said earlier, that your head gasket could be bad (Mercedes is notorious for defective head gaskets), and if so, you should be able to check with a CO coolant leak checker. When you shut down your diesel, the coolant is around 20psi, and is around this pressure for quite a while; if head gasket is bad, your coolant could be ever so slowly leaking into one of your cylinders, enough to cause what your symptoms are. You should have a bit of extra pressure build-up when you open the radiator cap on a COLD engine after about 5 minutes warm-up, but not necessarily so. Also, it would clean itself out fairly quickly; too much drainage will create hydraulic engine lock-up, and you will know when this happens

I would tend to lean towards the fuel-related dead cylinder(s) diagnosis that the others suggest, however, given the time duration for warm-up that you speak of. Could also be low compression in one or more cylinders.

P.E.Haiges · #12 08-16-2004, 12:09 AM

Jim,

If a mechanical injection Diesel stops while running, it is almost always caused by lack of fuel. Have you checked the fuel strainer in the fuel tank? Could either of the other fuel filters be plugged?

P E H

DieselAddict · #13 08-16-2004, 12:47 PM

Did you try leaving the glow plugs on for a longer time? Normally you should leave them on for about 15 seconds before a cold start. Make sure your relay doesn't click before this as that would indicate a defect. If that doesn't fix it it may also be your idle governor adjust pin on the back of the IP. It should not be all the way in as that may starve the engine of fuel. Also make sure you idle isn't set too low. It should be around 750 when warm (that's set with a different pin). I have also found that heavier oils (15W-) can sometimes calm down a shaky cold engine.

JimmyL · #14 08-16-2004, 01:22 PM

Believe me, I don't know enough to discount what anyone has said. When I think of white smoke caused by a head gasket issue, I usually have seen more of a 'steam'-type white smoke, and mine is thicker than that. I also have no symptoms of oil in my radiator, or coolant in my oil. I can see the glow plugs causing this I guess, if all cylinders aren't firing properly for a while. But they ohm out OK, and the glow plug relay is working correctly. I also have replaced it with no change to symptoms. I also tried waiting 30 or so seconds glow time, with no change. But, when car is hot it starts just like it should, so there is an anomolly. As mentioned above, fuel tank has been drained, screen was removed and found to be almost new, filters have been changed.
The missing is horrible, as it sputters and shakes with vigor. And the thick white smoke surely means something, but I simply don't know what. Frustrated!!!
JL

DieselAddict · #15 08-16-2004, 03:03 PM

Low compression could also be the cause as could bad injectors. I think a compression check would be a good idea. This way you or your mechanic can also pop test the injectors as those are often pulled out for a compression test. You don't have any gasoline in your tank do you? :p