You should check the crankcase breather pipe that starts at the top of the valve cover and goes into the turbo's intake. You can carefully disconnct the pipe at the bottom where it enters the turbo intake, then start the car you should feel a flow of crankcase gases exiting the pipe end proportional to the engine speed. If you don't feel that gas flow out of it, the pipe or its elbow fitting maye be clogged. You have to carefully pry/lift the elbow out of the grommet in the valve cover, it will be slightly easier if the engine is at operating temperature. You can also make it a little easier if you spray the elbow and grommet with some WD40 or something similar. Use a screw driver under the elbow's lip while lifting with the other hand. Once you get the elbow out of the valve cover you can then remove the other end from the turbo intake.

If this pipe and elbow are not open and free flowing the accumulating crankcase positive pressure will actually act against the vacumm shut off solenoid's diaphram from the inside eventually shutting down the engine. The symptoms are a sort of what appears as a low power/fuel starvation issue, excessive smoking ( I mean fog the block with clouds of smoke excessive!), and upon application of increased throttle the engine often lugs and then dies.

Tested the breather tube like billybob said, its definitely clear of any plugs, ditto with the vent holes on the valve cover. Removed the turbo and EGR and cleaned the h*** out of the valves, and physically blocked off the EGR altogether with a plate. When I took off the intake manifold yesterday, I realized the ALDA is completely missing! After looking at the vacuum diagram (http://i323.photobucket.com/albums/nn447/Jeremy5848/1987%20Mercedes%20300D/Vacuum603.jpg) I'm pretty sure the pressure sensing tubes that go to the ALDA and then the switch-over valves are simply disconnected.

I've read in other threads that removing the ALDA will have no effect on engine performance, but is there any way the pressure-sensing tubes should be hooked up in order to bypass the ALDA while keeping pressure in the tubes? Do they have any other function other than to provide pressure to the ALDA?

If you're talking about the vacuum lines serving the ALDA and switchover valve, just to give the ALDA a pressure signal and to shut down the boost enrichment to protect the engine if the wastegate fails.

__________________

Gone to the dark side

- Jeff

So, after blocking off the EGR and cleaning out the wastegate I can start the car and let it idle with no trouble. But the car has literally no power when driving. When it is in idle I can rev up to 4k, but once its in drive I can have the accelerator floored but the car will barely inch along. What am I missing?

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1986 300SDL: 386K, 200K on Engine w/#14 Head

Transmission?

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Greg
2012 S350 BlueTEC 4Matic
2007 ML 320 CDI
2007 Leisure Travel Serenity
2006 Sprinter 432k
2005 E320 CDI
1998 SLK230 (teal)
1998 SLK230 (silver)
1996 E300D 99k, 30k on WVO
Previous:
1983 240D, on WVO
1982 300D, on WVO
1983 300CD, on WVO
1986 300SDL 237k, 25k on WVO (Deerslayer)
1991 350SDL 249k, 56k on WVO - Retired to a car spa in Phoenix
1983 380 SEC w/603 diesel, 8k on WVO
1996 E300D 351k, 177k on WVO

First of all, "literally no power" means the engine won't run at all, that's no power, and that's literally. I hate mis-use of the word "literally", the word has no purpose.

Anyway, did you ever go through the suggestions in post #5? What were the results?

Did the turbo spin freely? Was the inlet pipe from the air-filter clear of significant oil and crud? Did the engine run without smoke without the air-filter plumbing attached? How does the output/crossover pipe look inside?

What about blowby? Does it puff like a locomotive with the oil-fill cap off? A 60x should have no blowby there.

More information should yield more answers and suggestions.

__________________

Gone to the dark side

- Jeff

Sorry about the lack of details. I've got the flu and sometimes I forget that people can't read my mind over the internet.

The turbo was in good condition when I checked it out. There was no play on the impeller, and it spun freely.

Currently I am getting a good idle with the turbo intake pipe disconnected from the air flow meter box, and smoke is reduced but not eliminated. This pipe did have a good coating of crud on the inside.

Blowby is noticeable. It doesn't blow the oil fill cap off when loosened but when off you can see a chug of vapors coming out.

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1986 300SDL: 386K, 200K on Engine w/#14 Head

"blowby is noticable" is not what I've experienced with 603s, sounds like there is either an issue with a stuck ring or other oil intrusion into a cylinder, or a problem with the crankcase ventilation system.

Looking at the exhaust manifold from below, is there any black/oily area around one or more head/manifold junctions?

Sorry to hear about the flu, ... I'm hoping to miss that train this year.

__________________

Gone to the dark side

- Jeff

Also, I forgot to mention that the oil pressure at idle is a constant 2 bar. The oil level indicator light is on, but when checking with the dipstick the level is near maximum - not low at all.

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1986 300SDL: 386K, 200K on Engine w/#14 Head

2bar at idle is very good / normal. The oil level sensor is on the side of the pan, could be unplugged/damaged, and the sensor does go bad occasionally.

__________________

Gone to the dark side

- Jeff

Try opening the clamp where the exhaust connects to the turbo. There may be too much back psi from the exhaust to let the engine breath properly.

I'm sorry, but i forgot to mention that I have done this as well. It has no effect on performance.

As far as blowby is concerned, I have checked it again and I don't think it is present in a major way.

I started the car again today, and THE SMOKE IS BACK. The engine is shuddering and killing itself just as bad as before.

I have yet to perform a compression test. I haven't been able to get ahold of the equipment yet. But as it seems to me the problems the car exhibits are symptomatic of either too little air or too much fuel.

As far as I know I have eliminated the possibility of air problems as the culprit by bypassing the whole intake up to the turbo and making sure the charge air pipe and manifold are clear. Is there any way the IP is bad and severely overfueling the engine? Is there any way this could be related to the vacuum/EDS system? Or, in a worst case scenario, could this be a case of oil being sucked into the cylinders? If a cylinder was sucking up oil during normal operation, would that explain why it would ruin fine after standing for a week, but soon be choked by thick smoke and stalling soon after that?

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1986 300SDL: 386K, 200K on Engine w/#14 Head

Have you checked to see if you are getting boost from the turbo. Attach a line into the intake manifold, you should be getting around 12 lbs. This needs to be checked while driving the car, and over 2000 rpm.

That's impossible because I cannot get to 2000 RPM when in drive. That is the problem.

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1986 300SDL: 386K, 200K on Engine w/#14 Head

Post your location in your user control panel, someone close may be willing to get together and help you troubleshoot.

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Regards,
Ian White

1995 E300 Diesel w124 OM606
2014 E550 w212 M278 biturbo

2001 BMW 740i E38 M62 (past)
1981 300SD w126 OM617 (past)