You read it correctly, I had sparks coming from my tailpipe during an Italian tuneup.

I went on a nine hour trip to pick up a lawn mower and some other stuff. All the stuff was on a trailer I was pulling. Total weight I will guess at 2500 lbs.

I knew there was a large hill coming up. So I flored the peddal. The hill was about a mile and a half up one side, at an average 35 or so degree grade. I kept the peddal pushed to the floor the entire cimb up the hill.

After reaching the top and starting to decend the other side I pegged the speedometer at 85 for a minute or so. Probably reached 95 to 100 mph.

(It was 3:00 in the morining and I made sure no other vehicles were around. I don't ever want to hurt someone whith my crazy stunts.)

Then I let off the peddal and shifted to nuetral. Then gunned the engine to its max rpm several times, letting off quickly. Thats when the sparks started shooting out the exhaust pipe

Scared the heck out of me at first. I thought it had caught fire !!! or I had blown the transmission, engine, rear end ?

It runs better now, but I wonder what caused the sparks ??

Italian tune up to the extream. brought to you by your frindly nutcase, RichC.

Thank You

( do not try this at home ) ( I am not suggesting you do this with your car ) ( Do not try to sue me for reading this and then going out and doing something stupid ) ( I am not responsible for others stupidity, just my own )

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When the power of love overcomes the love of power the world will know peace.
Jimi Hendrix

Having done what sounds like the some thing a time or two I would guess that sparks were from deposits built up in the exhaust system that were superheated by the "tune up" and then blown out the tailpipe. Not necessarily healthy for the engine to run that hard for that long but if the engine is running O. K. now it is probably cleaned out a little.
My experience with this symthom was with an engine that was using a little oil and had heavy deposits in the muffler that burned out at extended periods of full throttle under load, (like pulling a trailer uphill).
Al

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2007 Mini Cooper 4K miles
1993 300E 2.8 120K miles
1961 Morris Minor 42K miles
1965 Morris Minor 23K miles
1997 Ford F150 235K miles
1987 Ramcharger 202K miles
1984 Chevy C-30 farm truck 88Kmiles
1968 XKE 59K miles
2001 Harley Softtail
2003 Harley Roadking

What amazes me is your car's capability to pull such a load up a steep incline. What was the speed it slowed to?
As far as the sparks out the tailpipe. If it were a gas burner, I would say it was backfire or afterfire after such a high rev.
Another time with flames out the tailpipe I can remember is from my childhood. Batman & Robin were driving. Paul.

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1984 300CD red/blk 290,000 partial resto
1980 240D 4 sp Brn/palomino gone
1997 Mazda Miata STO edition wife's baby
1988 Lincoln Mark VII LSC next resto
1986 Subaru GL wagon daily
1993 Isuzu pickup field beater
2008 Honda Civic EX-L 5sp wife's new car
1978 Honda XL350
1974 Honda XL70 my Calif. ride in HS

This car amazes me also. Bought it on eBay for $810.00

I think I slowed to about 50 or so going uphil. My guess of the grade of the hill could be way off.

__________________

When the power of love overcomes the love of power the world will know peace.
Jimi Hendrix

A 6-8 degree grade is pretty steep, a 35 degree grade is an Olympic ski jump.

I wouldn't want to see a 6 degree grade.........that's a 10% grade. Most steep hills on a limited access highway are in the 6-7% range..........about 4 degrees.

A couple of the hills in San Francisco are 32% grades........about 18 degrees.......and they seem like a mountain. You definitely need first gear for them.

You're right, that's very steep. There are some mountain roads around here that may be that steep, but not many. The steepest highway grades here are also about 7% (Vail Pass on I-70 is 10,666ft with a 7% grade) and that's still pretty steep.

Sparks are bad news. Typically they are tiny bits of metal.

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green 85 300SD 200K miles "Das Schlepper Frog" With a OM603 TBO360 turbo ( To be intercooled someday )( Kalifornistani emissons )
white 79 300SD 200K'ish miles "Farfegnugen" (RIP - cracked crank)
desert storm primer 63 T-bird "The Undead" (long term hibernation)

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Can you hold 70 mph with the W123 on a 7% grade?

I'm quite sure the SD cannot hold it.......on an even lower grade......maybe 5% or so.

I hope they weren't sparks. Hopefully what he was seeing were hot bits of carbon fly out of his exhaust. I've seen a few post by MB owners seeing this while doing Italian Tuneups at night.

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'81 MB 300SD, '82 MB 300D Turbo (sold/RIP), '04 Lincoln Town Car Ultimate

Sooner or later every car falls apart, ours does it later!
-German Narrator in a MB Promotion Film about the then brand new W123.

A 35% grade would be a drop of 35cm every meter.

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1982 300CD Petrol/Black Leather

Yeah, maybe he was getting these kinds of speeds and sparks out the tailpipe... downhill.

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1984 300D Turbo Diesel - 211700+ mileage (now sold)
http://www.maj.com/gallery/Ned/benz/sig.jpg
In any of my posts, it is safe to assume
that I'm talking about this car.

It's been a while since I've had the 300D up there. As I recall, my maximum speed was more like 65 or so (with 3.07 gears). I could stay with the traffic OK, but I wasn't winning any races. The elevation doesn't help either.

Yes, the 2.88 gears in the SD and the larger tires seem to limit it's maximum speed to about 60-62 on such grades.

I've found a new way to save fuel, however.........take those hills at 60 mph...........the rack position is about 1/2 of the position necessary for 64 mph.........quite interesting actually.

The SD did 31.47, again......on the last tank.

I dont think sparks are a bad thing. You just got the whole exhaust hot enought to burn carbon deposits. This happens all the time on locomotive engines. There are federal requirments to clean certain exhaust pieces to prevent fires on the right of way.