How stinky is your car? - PeachParts Mercedes-Benz Forum

JHZR2 · #1 03-23-2011, 08:45 AM

Im talking about my 82 300CD. Great car, lots of power, very good economy (28+ MPG). Thing is, it stinks. Burns no oil, no appreciable blowby, injectrors popped and balanced, chain stratch less than the first tick mark on the harmonic balancer when the marks on the cam tower are aligned.

But when I start the car, if it idles in place for more than 5 seconds, Ill have a black soot spot on my driveway. Since I back out of my driveway, if Im doing so with the windows down, I get a LOT of foul diesel exhaust.

There is no black smoke visible during daylight. The car will make the usual soot in the headlights of the car behind when I get on the throttle. However I do see a slight bit of soot in the headlights behind me at night during normal operation.

My 240D doesnt smell nearly as strong under cold startup or operations. Neither does it show the soot in the headlights nearly as much (though it doesnt have boost/compensation for boost). While Im familiar with the level of smoke one will see in the headlights based upon my previous pristine and well-characterized 83 300D, Id say that my CD is a bit more smoky and a lot more stinky at cold start... Yet it runs so well.

I do run maintenance doses of diesel fuel additive. I burn zero oil.

Thoughts? Might this be an IP timing issue?

Thanks!

vstech · #2 03-23-2011, 08:48 AM

has the alda been adjusted?

JHZR2 · #3 03-23-2011, 08:58 AM

Nope, sealed.

vstech · #4 03-23-2011, 09:01 AM

Hmm. have you checked to see if the alda itself is loose?
how long have you driven the car? you could just have a ton of soot from P.O's crappy service/driving.
BIG italian tune up, and clean air filter could cure you.

JHZR2 · #5 03-23-2011, 09:23 AM

No not for looseness. Have had the car since Nov 09, drove it xc. Po kept the car well, I have all the receipts. Valves all good.

That's why I was thinking timing of ip. Air filter/soot oil mix in intake due to turbo oil leak inside (if that is the cause of the oil in my u-tube) might be related.

Will search for checking the Alda for leaks, and throw in a new AF.

I know my turbo doesn't overboost - it was right at 11.7psi before messed with linkages, so banjo is clean and turbo boosting, fwiw...

TX76513 · #6 03-23-2011, 09:34 AM

Probably just injectors. 29 year old car....the atomization process causes the holes to erode and become larger causing more fuel to cylinders thus smoke.

JHZR2 · #7 03-23-2011, 10:12 AM

Injectors were popped and balanced with new nozzles installed within the last 3k. This was the case before then. Doubt it is an injector issue...

funola · #8 03-23-2011, 10:57 AM

I think a small amount of dry soot in our old diesels is normal, especially after cold starts, when the fuel is not burned as efficiently. Some of that soot can also be from years of accumulation in the exhaust getting blown out. The best thing you can do is give it a nice Italian tuneup often to burn/blow the soot up & out.

RAYMOND485 · #9 03-23-2011, 01:30 PM

1984 300D TURBO 155K
USE STARTRON ITS BLUE GET IT FROM A BOAT SUPPLY ITS FOR FUNGUS IN THE FUEL, IT CLEANS INJECTORS AND NO MORE BLACK IN THE FILTERS, GOOD ENGINE POWER

tbomachines · #10 03-23-2011, 01:56 PM

Quote:

Originally Posted by RAYMOND485

1984 300D TURBO 155K
USE STARTRON ITS BLUE GET IT FROM A BOAT SUPPLY ITS FOR FUNGUS IN THE FUEL, IT CLEANS INJECTORS AND NO MORE BLACK IN THE FILTERS, GOOD ENGINE POWER

different issue

To OP: Sounds like the ALDA could be adjusted. Smoke at idle is fairly normal, the soot spot is not (although idling my car in the winter I did see some soot in the snow, but just speckles). Smoke at WOT indicates the turbo is not pumping enough air to supplement the fuel, although 11.7 psi is not too bad. Take it out for an ITU and see if that clears the exhaust, report back.

Yak · #11 03-23-2011, 08:42 PM

Burn zero oil per how many miles per oil change?

If you're a religious every 3000 miles, maybe it's just a small enough quantity getting by the turbo to not really be noticeable on the dipstick but does appear in the turbo and get burned.

Various speculative things could contibute to it being worse on start or in your driveway: e.g. slow driving prior to parking in the driveway keeps the turbo from spooling and pumping the oil out, so it starts pooling prior to shutdown. On startup there's a larger quantity there, hence the smoke and smell on startup.

It probably wouldn't take much, maybe a teaspoon or so?

JHZR2 · #12 03-23-2011, 11:21 PM

Could be, but really there is no smoke other than the typical what one sees in another's headlights, especially when on the boost.

Even after running a few hundred miles and then coming back to idle, it still smells stromg.

vstech · #13 03-23-2011, 11:39 PM

if the EGR is open at idle it'll cause soot. possible issue there. is yours operational? also, a stiff turbo bearing or low oil supply, could cause low airflow. possibly blocked intake... may be a timing issue.

scottmcphee · #14 03-24-2011, 12:00 AM

Fouled cat?

pawoSD · #15 03-24-2011, 12:15 AM

Quote:

Originally Posted by JHZR2

Injectors were popped and balanced with new nozzles installed within the last 3k. This was the case before then. Doubt it is an injector issue...

Key here is what type of new nozzles? Bosch? Monark? Bosio? I've found the Bosio to be very good and the Monark to be extremely good. Bosch aren't made in Europe anymore....so not worth using.

Foul exhaust is most likely over fueling or poor atomization resulting in a slightly less-complete burn, even if not readily visible through smoke.