Well, i'm steadily making progress with the repairs on my new 85 190e 2.3. I replaced the drivers side motor mount and cured a lot of the clunk going into reverse but it still engages pretty harshly. Found out my valve noise was coming from a flattened cam lobe on #3 intake, luckily I was able to pick up a new cam on ebay real cheap so I'll stick that in when it gets here. Belt tensioner shock is blown but I got one of those coming off ebay too. Thermostat cover is cracked and leaking, still gotta find one.
But now that I can drive it around a little I see that it puts out a LOT of smoke when you gas it, it even smokes faintly at idle. Starts great hot or cold (no pedal cold, a little pedal hot), idles steady at 750 warm, doesn't overheat, runs strong but smokes.
Compression was 150# across the board warm and a cylinder leak down test showed 20% +/- 2% with #3 leaking the most at 22%. I've seen motors with higher #s than this that didn't smoke. The car shows 187k. The tailpipe is sooty not oily which to me indicates excess fuel but it just runs so damn good I can't believe a mixture rich enough to smoke wouldn't hurt performance or driveability.
Any ideas out there ?
Thanks

Did you take a look the sparkplugs?
Are thy sooty or oily?
I was having the same problem and it was the oxygen sensor.

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1999 Porsche 996 Carrera Convertible
1994 420E - SOLD
1986 300E - SOLD, what a car
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they're sooty and wore slap dab out. i took it for a longer drive today (about 5 miles) and the smoking defineatly improved (lessened) by the time i got back. when i started it was putting out great billowing clouds and after a few miles it calmed down to a light haze. i think before i freak out over it i'm going to replace the bad camshaft, change the oil & filters and do an ignition tune up.
now i found a new gremlin though. during the test drive i started hearing a click click noise (like a relay)coming from i think the center console area but it might be underdash on the passenger side. it was a pretty regular click click while the car was in motion (but not speed sympathetic). it was also intermittent and even did it a few times with the car at rest. bizarre

I recently worked on a friend's 1990 190E 2.6. Here are some things i did:

It was burning lots of oil most noticeable at start up and would not pass smog. I found a MB TSB from May 1992 that addressed the most common cause of oil consumption in this engine and it also lists your engine (102.961). Apparently these engines had poor valve stem seals. The new replacement ones are made of Viton and will last longer and work better from the start. Nevertheless, i performed a compression test on each cylinder before digging in as I wanted to see how the sealing of the rings and valves was. compression was high and consistant as with your car so i went ahead with the seals. I was able to borrow a valve spring compressor from Autozone for free. They have a great tool loaner program with no questions asked except a deposit (you don't even need to buy parts from them! Dont forget to compress air in the cylinder your working on or you could drop a valve. Make sure that cyl is in TDC or the crank will rotate from the compressed air. Before loosening the valves hit the top of the valve retainer with a soft dead blow hammer. you need to or else the keepers can't be removed. Put clean rags in the area so you don't drop a keeper into the engine. A magnet should be handy.

Anyhow after an afternoon of work and several months gone by he no longer needs to add oil. Before this he was told by a mechanic that it would cost $1200 to redo the head. I can't believe how easy it is to get ripped off. The valve stem seals are very2 cheap. It's a non brainer if the cam is coming out anyway. MB has another TSB about the camshaft lubrication oil pipe. In July 1991 they started using Locktite 642 on the screws holding the pipe. The screws on engines before this date tend to loosen causing lubrication problems for the cam. funny enough one of the screws I undid felt only hand tight. were any of yours loose? Don't forget to degrease the holes before putting back the screws. One drop of loctite per hole is enough and you need to wait 15 min after tigtening before starting the engine up. Better take care and respect MB torque value on these. it's easy to over do it with little screws (strip them) especially when you are thinking about how they got loose the first time.

There is also a 1989 MB TSB on your camshaft.


Finally I replaced the tensioner, smog pump, alternator, engine mounts and the trans mount. On this particular car the engine mount bottom bolt was a 8mm allen. It was on so tight that even after hammering it to set up a vibration and lots of WD40 it stripped. I'll share a trick with you on this one for anyone interested. Just take a 15mm 12pt socket and hammer it onto the bolt. the 12pts grip in perfectly and the bolt came of with a breaker bar. I can't imagine why this bolt was on so tight in the first place (impact hammer?). Now MB only stocks regular bolts instead of allen head when you buy new ones as i found out after stripping one of the existing ones.

Good luck and thanks for you advise to me earlier today about the brake booster,
Elliot

i think you may be on to something with the valve guide seals. the car really started smoking after being nose-up on jackstands all night after replacing the motor mount. that would have submerged #4 valves in oil allowing it to drain down past bad seals into the cylinder. i will defineatly be replacing the seals. thanx

Don't be surprised if the seals look good. All of the ones i replaced were intact and only a bit stiffer from heat/age. But in the end it made all the difference with new ones. Don't forget to use the insertion tool (actually just a dinky plastic sleeve) when you put on the seals. they come with the valve stem seal kit and prevent the valve stem from damaging the seals as they slide on.

just thought of something. since i will need to do this with the cam and rockers removed how do i keep the cam timing from slipping while i rotate the crank? remove the rockers and reinstall the bare cam & blocks?

I'm not to sure about how you should proceed without the cam on but it may turn out to simplyfy your job. With the cam off all the valves should be seated so you can put the compressed air into any cylinder and the valve will not fall. but here is the problem: the crank will rotate because of the compressed air pushing the piston down so you may need to find a way to lock the crank from rotating (in either direction). Maybe it can be done at the torque convertor? You better get some other opinions or think through it more as i am not certain about this without putting in more thought.

i'll do some more research on this but i'll probably pull the rockers and shafts for inspection anyway and put just the cam & blocks back on to do the seals. i replaced the cam chain on this car last year for the previous owner and managed to drop it in the motor after splitting the master link. took me a full day to fish it out and another day to thread the new one without pulling the front cover. like building a ship in a bottle.