Engine going south??? - PeachParts Mercedes-Benz Forum

JimmyL · #1 08-18-2004, 08:17 AM

A couple of days ago I had a thread about my '80 300TD being hard to keep running after start-up, and how it smoked for 2-3 minutes. Heavy white smoke. Well, all of the above is the same, but it now smokes all the time, white smoke, non-steam, as I clouded the entire road for an 1/8 mile yesterday. It also seems to have developed a slight miss when driving. I'm going to try and find a place to have my compression tested, and I'm guessing this may reveal the problem?
How much do mechanics usually charge for a compression test? I only ask this as it may determine how soon I address this problem. Taking my oldest daughter to college Friday, so yall can guess where most of my money is going. I've already retired "The Flash" from daily driving, but I've got to address this whether I keep it or sell it.
The car is winning..........
Jimmy

kerry · #2 08-18-2004, 01:54 PM

First thing I would do is pull the oil breather hose off and run it for a while to confirm that you are not sucking oil out of the crankcase and into the intake. Much cheaper than a compression test. Also, make sure the oil level is correct. Also make sure you are not sucking oil into the intake from the vacuum pump. Finally, make sure you are not sucking oil from the turbo into the intake. I'd say all those problems are more likely than a sudden catastrophic compression failure.

pberku · #3 08-18-2004, 02:26 PM

Also make sure that you don't have bad diesel fuel.

JimmyL · #4 08-18-2004, 02:43 PM

OK, I think I can rule out bad diesel, as I have drained the tank, plus filled up at several different places. I can rule out the turbo line, as I am a non-turbo. I will disconnect oil breather hose first. I'm assuming that is hose from valve cover to air breather. How would I check for oil being sucked in from the vacuum pump? Thanks so much for the help so far! I will check this when I get home. Any other ideas are most welcome.
Jimmy

kerry · #5 08-18-2004, 02:48 PM

On the models that can suck oil from the vacuum pump, there is a clear plastic line going from the pump to the air filter. Make sure there is no oil in this line.
I thought the 80 TD's had the turbo and that only the 79 wagons did not?? Is it 81?

JimmyL · #6 08-18-2004, 11:01 PM

I think the turbos started in '81 on wagons, but wouldn't swear to it. Just know mine doesn't have one. I don't have any type oil line, clear or not, going to the air cleaner other than black hose from valve cover over to hole in air cleaner.
Went by an indy today in the same parkinglot as one of my customers(not in my MB), and explained my situation to him. He said it sounded like IP problems. He said it sounded like it was running rich, which wouldn't let it idle correctly, and would cause it to smoke. He said it would run OK at speed, which it seems to do. I asked him about fixing that and he recommended using the car for parts and buying something else. Basically said the cost of the IP work isn't worth it for the car.
What do yall do when you have IP problems? Does his theory sound plausible?
Jimmy

kerry · #7 08-18-2004, 11:11 PM

I can't recall an instance on this board where someone with the symptoms you described discovered it was a bad IP pump running rich. I agree it's running rich, but I think the source of the fuel is something other than the IP pump.
You've probably got the newer style vacuum pump without the line going to the air cleaner.

JimmyL · #8 08-18-2004, 11:31 PM

If I have the wrong vacuum pump, would it just start causing the smoking and idling problem out of the blue one day? Ive had the car for 3 months, and this all started rather abruptly. I'm guessing there will be a place on the pump where the line should be coming from?
I will check that out tomorrow. Thanks for your ideas...I hate not being able to use it.
Jimmy

kerry · #9 08-18-2004, 11:37 PM

I don't think the pump is wrong, just different. I don't believe the newer pump can fail in such a way as to cause the symptoms you describe.

JimmyL · #10 08-18-2004, 11:54 PM

Thanks Kerry. Does this lead me back to the IP?
One item of note, and I just mention it to clear my own mind, but this started not too long after I adjusted my valves. Just to ease my mind, I did go back in to double check my specs, and the intake and exhaust are all adjusted correctly. That is a fairly straightforward procedure and they are correct, intake at .1mm and exhaust at .3mm. They were not way out of spec to begin with.
It is just shocking at how bad it smokes....

Edit: It just dawned on me. I have gone from 20-22mpg to 19mpg for a couple of tanks, to 17mpg on the last tank. Running rich sure seems obvious. Sorry for leaving that out. DUH!!

pberku · #11 08-19-2004, 12:01 AM

Can you post a picture (or pictures) of your smoking car while its smoking. It may help put things in persepctive

JimmyL · #12 08-19-2004, 12:11 AM

You bet. I'll try that tomorrow, but will need help, as someone has to keep it running while the other takes the picture. I would have had a great picture the other day, of about an 1/8 mile fog bank rolling down the street. Literally! Smoked out both sides of the rode, and just hung there for several minutes.

psfred · #13 08-19-2004, 07:30 PM

Late injection timing or a toasted IP.

Check timing chain stretch, make sure you actually have valve clearance on all the valves, set start of injection.

The sudden occurance bothers me, it's very unlikey this is low compression appearing suddenly UNLESS you set some intakes to exhaust clearance and vise versa (don't ask how I know this!).

Later model 617's have a crankcase vent for the vac pump, they won't blow oil down the intake, and that's blue smoke, not white.

There is also a possibility you have a couple of bad injectors that are squirting fuel instead of a nice mist, but they should knock pretty bad if they do.

Peter

kerry · #14 08-19-2004, 07:51 PM

Very high amounts of oil in the combustion chanbers will burn white and not blue. I had an Austin Healey pulling oil directly out of the crankcase into the intake via a failed PCV valve. It left a HUGE cloud of white smoke even visible after I had driven around the block. Not a hint of blue in it.

JimmyL · #15 08-20-2004, 09:05 PM

Just posting example pics of the smoke. The hose from valve cover to air cleaner is not attached at this time. No real noises out of the ordinary except for the sputtering and coughing and missing. No loud knocks in other words. I would welcome ideas on how to procede at this point. Reminder, the fuel milage has steadily gone down from 22-23 to just over 17 on the last tank, if that is helpful. Heavy smell of diesel, and the cloud lingers for quite a while.
Jimmy