85 300TD - Slow, Smokey, Irregular Power - Page 2 - PeachParts Mercedes-Benz Forum

mannys9130 · #16 02-04-2016, 07:25 PM

Better yet, just test/clean the EGR and verify operation before disabling an important emissions device.

southofantarctica · #17 02-06-2016, 02:25 PM

Had some time to update. Been working a lot lately and haven't had much time for trouble shooting. Been driving it 7 miles each way to work. Probably not the best idea.... But that's the way life is right now.

Power seems to be sloooowly going down. No long able to get into the upper RPMs. Seems that 3000 is about the limit. I've also noticed that 3/4 throttle appears to be faster than WOT. The best way to drive is get into the next gear as soon as possible.

Boost gauge installed. I have the waste gate hose blocked off and max boost is 5psi at 3000, average is 2-3psi after 2200.

Had the wife help test the theory about the blowby hurting performance. After the engine was warm, in park, she held the accelerator at WOT. Engine revved up to almost 5000 then immediately dropped down to about 2900. While she held the peddle down, I removed the oil filler cap. Engine immediately surged to 4900 and held there until I put the cap back on.

toomany MBZ · #18 02-06-2016, 04:02 PM

Partially or completely clogged vent pipe?

From the cam cover to the air cleaner.

Clogged pressure line rom the manifold to the ALDA?

barry12345 · #19 02-07-2016, 05:06 AM

Quote:

Originally Posted by toomany MBZ

Partially or completely clogged vent pipe?

From the cam cover to the air cleaner.

Clogged pressure line rom the manifold to the ALDA?

Hopefully number one. Unfortunatly otherwise not great.

I was happy to see you did the blow by test properly. This regarding testing for the injection pump shutoff possibility. Was there much oil spraying out with the cap off? Just my curiosity.

Around the time these engines where built straight 40 base oil was the standard. I am going to make a suggestion. If you try it and it works post the oil consumption rate.

Partially depending on what is wrong in the engine will determine the results. Change the base oil using straight 50 grade oil including a quart of miracle mystery oil. The thinner miracle mystery oil will reduce the oil viscosity to about 40 grade. Short fill the engine first leaving room for the quart of solvent oil. If the engine does well with the straight 50 add the mystery oil. Chances of it working are better than 50/50. I just hope it is warm enough in Texas in comparison to where I am. At this point buy the cheapest 50 weight oil.

Is there any evidence or knowledge this engine has seen vegetable oil in your opinion? If so the miracle mystery oil should loosen those rings if they are stuck somewhat. It would take quite some milage but the stuff does work. Wear or scoring problems of course would not be impacted. I do have some experience working around some problems using heavier base oil.

Anyways it was nice to see you found the primary problem without a lot of work. Also in the process you got me thinking. As the wife says that is dangerous.

I quickly developed a test mentally and will have to think about it a little. It is a test to determine if the intake valve guides or guide seals need attention. You cannot use oil consumption as a reliable indicator.

A simple test might be to take the connecting link from the turbo off. This removes the positive pressure on the intake guides and rubbers the turbo generates. Engine should still rev up as there is no load. If the engine then kept running well and did not shut down partially or otherwise. It would indicate to me there is too much air being blown up the intake guides by the turbo.

You could contribute a lot of knowledge about these engines simply by doing your blow by test again with the turbo air input off. Before changing the oil of course. It could indicate that we have missed the concept of pressurized leakage up the intake guides. Or that it is even a possible contributor.

I do not think they could pass enough air to totally shut down an engine but they might contribute enough to put the crankcase pressure beyond limits. When combined with the cylinder blow by

I have wondered for a long time if the shutdown with substantial base blow by pressure was intentional by design or just a fluke of design. Technically I can think of another approach but it is best left until the engine is run on the modified 50 weight oil. Seeing how things go there first is important. The last question. Does the engine still cold start fairly easily?

southofantarctica · #20 02-07-2016, 05:01 PM

Quote:

Originally Posted by barry12345

Hopefully number one. Unfortunatly otherwise not great.

Unfortunately, the line is not clogged.... Seems that there is too much blowby for that hose to handle. Instead of having it run to the stock catch can, could I run it post air filter/pre turbo? Use the suction from the turbo to help evacuate the crankcase? Just a thought, seems like it could work.

I was happy to see you did the blow by test properly. This regarding testing for the injection pump shutoff possibility. Was there much oil spraying out with the cap off? Just my curiosity.

And there were copious amounts of oil flying out (well, enough to pool around the rag I was using)! The first time I tried it without a rag and blew oil all over everything.

Around the time these engines where built straight 40 base oil was the standard. I am going to make a suggestion. If you try it and it works post the oil consumption rate.

Partially depending on what is wrong in the engine will determine the results. Change the base oil using straight 50 grade oil including a quart of miracle mystery oil. The thinner miracle mystery oil will reduce the oil viscosity to about 40 grade. Short fill the engine first leaving room for the quart of solvent oil. If the engine does well with the straight 50 add the mystery oil. Chances of it working are better than 50/50. I just hope it is warm enough in Texas in comparison to where I am. At this point buy the cheapest 50 weight oil.

I just changed the oil 100 mile ago, with Shell 15-40 diesel. I'll look into the straight 50 weight. I had the car sit for almost 2 weeks with MMO in the cylinders, do you still think that it would be worthwhile to add? The current temp is 77, I don't think the thicker oil will cause any problems.

Is there any evidence or knowledge this engine has seen vegetable oil in your opinion? If so the miracle mystery oil should loosen those rings if they are stuck somewhat. It would take quite some milage but the stuff does work. Wear or scoring problems of course would not be impacted. I do have some experience working around some problems using heavier base oil.

Not that I can tell, I haven't found any of the gummy residue from old veggie like I did on my 300D.

Anyways it was nice to see you found the primary problem without a lot of work. Also in the process you got me thinking. As the wife says that is dangerous.

I quickly developed a test mentally and will have to think about it a little. It is a test to determine if the intake valve guides or guide seals need attention. You cannot use oil consumption as a reliable indicator.

A simple test might be to take the connecting link from the turbo off. This removes the positive pressure on the intake guides and rubbers the turbo generates. Engine should still rev up as there is no load. If the engine then kept running well and did not shut down partially or otherwise. It would indicate to me there is too much air being blown up the intake guides by the turbo.

You could contribute a lot of knowledge about these engines simply by doing your blow by test again with the turbo air input off. Before changing the oil of course. It could indicate that we have missed the concept of pressurized leakage up the intake guides. Or that it is even a possible contributor.

I am confused about this. Are you talking about separating the turbo from the intake manifold? Or disconnecting something else entirely?

I do not think they could pass enough air to totally shut down an engine but they might contribute enough to put the crankcase pressure beyond limits. When combined with the cylinder blow by

I have wondered for a long time if the shutdown with substantial base blow by pressure was intentional by design or just a fluke of design. Technically I can think of another approach but it is best left until the engine is run on the modified 50 weight oil. Seeing how things go there first is important. The last question. Does the engine still cold start fairly easily?

So far, so good. The engine starts and idles fine. Idle is better cold, both in and out of gear.

I also noted that there was a puddle of oil in the low side of the air filter housing. I'll have to keep an eye on that. I don't remember if there was oil there when I looked last time or not.

southofantarctica · #21 02-07-2016, 07:04 PM

Major update

I took it on a short test drive with the oil cap removed, but with a rag Jerry rigged covering the hole.

Whole. New. Car.

Power all through the band, 11 psi of boost at 2700rpms. Now I need to readjust the Bowden cable so it will hold gear longer.

Very very excited.

southofantarctica · #22 02-07-2016, 09:27 PM

0-60 time is now 24 seconds! While I know that is still a good bit slower than what a "good" engine should be, I'm stoked!

Still only getting 11psi, max boost. My waste gate is currently blocked off, so I would expect high teens at minimum. I know that I can only use 12-13psi, but seems like there should be more...

Tried to see if I could do any power breaking like my old 300D could, got nothing. Maxed out at 1700rpms braked.

barry12345 · #23 02-08-2016, 01:27 AM

Yes disconnect the turbo from the intake was what I meant.

Going from 15-40 to a straight grade at the higher end will reduce blow by and oil consumption. Hopefully enough to keep the car on the road and you can keep your drained newer oil. It may be reusable later.

It has always concerned me that the viscosity of a multi grade is a lot less when hot then a fixed viscosity oil. Since they say it protects as well I assume the molecular size of the additive making it a multi grade is much larger. The thinner base stock perhaps getting by the rings easier at the same time.

The miracle oil is going to take some time to work if it does so the car has to be at least serviceable for the period.

Putting mystery oil in the bores is different than the application in the base oil. You have the heating and cooling cycles to help as the solvent gets into the rings. Of course it can do nothing about excess wear.

The easy starting is far better than hard starting to decrease the odds of massive wear. I do not know if a serious overheat sometime might have removed the temper from the rings. My first instinct though is it should have got the compression rings first.

Since the car cold starts easily I suspect the rings where not cooked. It is really good there was no evidence of Vegatable oil as it reduces the chances of bore damage.

southofantarctica · #24 03-29-2016, 01:47 PM

Had a free chance on Sunday, changed the oil to straight 50, with a quart of MMO.

Time to see how well the experiment works. Initial report is everything is the same was with the 15-40. Possibly slightly quieter idle, but that could very well be wishful thinking.

I'll report back if anything changes.